Split cord malformation: Part I: A unified theory of embryogenesis for double spinal cord malformations.

Much confusion still exists concerning the pathological definitions and clinical significance of double spinal cord malformations. Traditional terms used to describe the two main forms of these rare malformations, diastematomyelia and diplomyelia, add to the confusion by their inconsistent usage, ambiguities, and implications of their dissimilar embryogenesis. Based on the detailed radiographic and surgical findings of 39 cases of double cord malformations and the autopsy data on two other cases, this study endorses a new classification for double cord malformations and proposes a unified theory of embryogenesis for all their variant forms and features. The new classification recommends the term split cord malformation (SCM) for all double spinal cords. A Type I SCM consists of two hemicords, each contained within its own dural tube and separated by a dura-sheathed rigid osseocartilaginous median septum. A Type II SCM consists of two hemicords housed in a single dural tube separated by a nonrigid, fibrous median septum. These two essential features necessary for typing, the state of the dural tube and the nature of the median septum, do not ever overlap between the two main forms and can always be demonstrated by imaging studies so that accurate preoperative typing is always possible. All other associated structures in SCM such as paramedian nerve roots, myelomeningoceles manqué, and centromedian vascular structures frequently do overlap between types and are not reliable typing criteria. The unified theory of embryogenesis proposes that all variant types of SCMs have a common embryogenetic mechanism. Basic to this mechanism is the formation of adhesions between ecto- and endoderm, leading to an accessory neurenteric canal around which condenses an endomesenchymal tract that bisects the developing notochord and causes formation of two hemineural plates. The altered state of the emerging split neural tube and the subsequent ontogenetic fates of the constituent components of the endomesenchymal tract ultimately determine the configuration and orientation of the hemicords, the nature of the median septum, the coexistence of various vascular, lipomatous, neural, and fibrous oddities within the median cleft, the high association with open myelodysplastic and cutaneous lesions, and the seemingly unlikely relationship with fore and midgut anomalies. The multiple facets of this theory are presented in increasing complexity against the background of known embryological facts and theories; the validity of each facet is tested by comparing structures and phenomena predicted by the facet with actual radiographic, surgical, and histopathological findings of these 41 cases of SCM.


Split cord malformation: Part II: Clinical syndrome.

Thirty-nine patients with split cord malformations (SCM) were studied in detail with respect to their clinical, radiographic, and surgical findings as well as their outcome data. Eight patients were adults and 31 patients were children. According to the classification endorsed by Part I of the SCM study, 19 patients had Type I SCM (6 adults and 13 children), 18 patients had Type II SCM (2 adults and 16 children), and 2 patients had composite SCM with both lesion types situated in tandem. Six SCMs were cervical, 2 were thoracic, and 31 were in the lumbar region. All 8 adults had pain and progressive sensorimotor deficits at diagnosis. Only 16 of the 31 children had symptoms, and among these, 14 had progressive sensorimotor deficits, but only 6 had pain. The difference in the clinical picture between adults and children is similar to that described in the tethered cord syndrome, except for left-right functional discrepancy, which was prominent in 8 children with SCM but rarely seen in tethered cord syndrome due to other causes. Cutaneous manifestations of either occult or open dysraphic states were present in all but 3 patients; hypertrichosis was by far the best predictor of an underlying SCM, being found in 56% in the series. Neurological deterioration in SCM was independent of the lesion type: the Type I:Type II ratio for symptomatic progression was 13:11. It was also independent of the location of the lesion: 67% of patients with cervical SCMs had symptomatic progression versus 64% of patients with thoracolumbar lesions. High-resolution, thin cut, axial computed tomographic myelography using bone algorithms was more sensitive than magnetic resonance imaging in defining the anatomical details of the SCM. Radiographic classifications of the SCM, using the nature of the median septum and the number of dural tubes as criteria, was always possible without ambiguity. However, whereas every Type I bone septum was identified preoperatively, only 5 Type II fibrous septa were revealed by preoperative imaging, even though a fibrous septum and/or other fibroneurovascular bands were found tethering the hemicords in every Type II case at surgery. Complete imaging studies also showed that all lumbar SCMs had low-lying coni and at least one additional tethering lesion besides the split cords, whereas only 1 of 7 cervical and high thoracic SCMs had a low conus and a second tethering lesion. The surgical goal for SCM was release of the tethered hemicords by eliminating the bone spurs, dural sleeves, fibrous septa, or any fibroneurovascular bands (myelomeningoceles manqué) that might be transfixing the split cord. Type I cases were technically more difficult and had a slightly higher surgical morbidity than Type II cases, especially if an oblique bone septum had asymmetrically divided the cord into one larger hemicord and one smaller, hence, very delicate, hemicord.(ABSTRACT TRUNCATED AT 400 WORDS)


Lateral cervical spine dislocation and vertebral artery injury.

Although anterior and posterior traumatic displacement of cervical vertebrae are commonly noted, and the devastating neurological deficits associated with these injuries have been amply defined, lateral displacement with fractures has been rarely recognized, and the clinical significance of this injury has been overlooked. This report describes five cases of cervical spine fractures with lateral dislocation. All patients had lateral and anteroposterior cervical spine radiographs as well as cervical angiography or postmortem study demonstrating either complete occlusion or significant impairment of flow of the vertebral arteries. Two cases had traumatic vertebral artery occlusion with secondary medullary and cerebellar infarction resulting in the patient's death. Vertebral artery injury apparently is not uncommon in this particular type of fracture. The diagnosis of these vascular injuries may require angiography or magnetic resonance angiography. A vertebral occlusion or dissection is a problem of considerable complexity, requiring individualized management depending on the patient's symptomatology, location and nature of the injury, and time lapsed since the injury.


High-resolution magnetic resonance imaging of experimental spinal cord injury in the rat.

The ability of magnetic resonance imaging (MRI) to display the anatomic changes after spinal cord injury in the rat were examined in postmortem specimens. With the clip compression technique, acute spinal cord injuries of three grades of severity were produced in adult male rats. One hour after injury, during which time physiological parameters were measured and maintained within the normal range, the rats were killed by transcardiac perfusion of formalin. The vertebral column containing the cervical and upper thoracic segments was excised and, after further formalin fixation, 20 contiguous MRI scans centered on the injury site were obtained using a spin-echo imaging sequence. The volume of signal acquisition for each image was 15 x 15 x 1.0 mm thick. The spinal cords were then removed from the vertebral column, sectioned, and stained for histological examination. Ten-micrometer serial sections of each cord were examined microscopically. MRI scans and microscopic sections at comparable levels were examined to determine the quality of anatomical detail and spatial resolution of the MRI scans. MRI scans with resolution of about 75 microns per pixel edge were obtained. At the site of injury, there was disruption of the normally well demarcated gray-white interface and variable areas of low signal intensity. Because of the resolution achieved, it was possible to determine that these low signal intensity areas were post-traumatic hemorrhages. Indeed, hemorrhages with dimensions of the order of 100 microns were detected on the MRI scans. Furthermore, by examining the serial sections of the cord, the extent of the injury along the cord could be determined.(ABSTRACT TRUNCATED AT 250 WORDS)


Origins and conducting pathways of motor evoked potentials elicited by transcranial magnetic stimulation in cats.

Spinal cord motor evoked potentials (MEPs-S) were elicited in cats by transcranial magnetic stimulation. The MEPs-S recorded from the epidural electrode at the first lumbar (L1) level consisted of four negative peaks (N1, 2.56; N2, 3.19; N3, 4.06; N4, 4.99 ms) followed by small, multiphasic waves. The mean conduction velocities of N1-N3 of the MEPs-S were calculated to be 90 to 115 m/s, which is consistent with extrapyramidal tract activation. A direct brain stem electrical stimulation and sequential transection of the spinal cord studies showed that N1-N3 of the MEPs-S originated primarily from the brain stem and conducted in the ventral funiculus of the spinal cord, which corresponded to the extrapyramidal tracts (e.g., the reticulospinal and vestibulospinal tracts). We also showed that N1 and N2 of the MEPs-S originated mainly from the lower medulla or upper cervical and that N3 originated from the lower pons or upper medulla (vestibular nucleus). On the other hand, N4 of the MEPs-S had a conduction velocity of 70 m/s, which disappeared by ablation of the sensorimotor cortex and pyramidotomy. A dorsal hemisection of the spinal cord, resulting in the disappearance of N4 of the MEPs-S, indicated that it conducted in the dorsolateral funiculus of the spinal cord. These results suggest that N4 of the MEPs-S originates from the sensorimotor cortex and conducts in the lateral corticospinal tract. MEPs-S by transcranial magnetic stimulation in cats constituted complex responses in both the pyramidal and extrapyramidal tracts.


Successful treatment of a malignant rat glioma with cytotoxic T lymphocytes.

Brain tumors are highly resistant to therapy. Their diffuse infiltrative nature and the relative inaccessibility of brain tissue to blood and lymph are barriers to surgical and cytotoxic treatments alike. The purpose of this study was to produce immune cells specifically reactive with an anaplastic rat glioma (RT2) and determine whether those cells could affect tumor progression in the brain. RT2-specific cytotoxic cells were prepared by priming rats in vivo with RT2 tumor cells and Corynebacterium parvum and stimulating the primed lymphocytes in vitro with irradiated RT2 tumor cells and interleukin-2 (IL-2). Cultured cells exhibited a high level of cytotoxicity against RT2, but not C6 (an allogeneic glioma), 3M2N (a syngeneic mammary tumor), or CSE (a syngeneic fibrosarcoma) tumor cells. To generate a model for therapy, rats were injected intracerebrally with RT2, generating progressing brain tumors, which killed untreated rats in approximately 2 weeks. To test the therapeutic potential of the effector cells, tumor-bearing rats were treated by intravenous injection of lymphocytes on Day 5 of tumor growth. Treated rats also received a 5-day course of systemic IL-2 beginning on Day 5. Treatment with IL-2 alone, RT2-primed spleen cells, or RT2-primed spleen cells stimulated in vitro with C6 did not affect rat survival. However, tumor-bearing rats treated with RT2-stimulated lymphocytes exhibited increased survival or were cured. Systemic IL-2 was an essential adjunct, because survival was not affected by treatment with effector cells alone. Therapy initiated on Day 8 of tumor progression lacked effect on survival.(ABSTRACT TRUNCATED AT 250 WORDS)


Mechanism of interferon gamma-induced protection of human gliosarcoma cells from lymphokine-activated killer lysis: division of lymphokine-activated killer cells into natural killer- and T-like cells.

The mechanism by which interferon gamma (IFN-gamma) decreases the susceptibility of the established cultured gliosarcoma line Gl-1 to lymphokine-activated killer (LAK) lysis was analyzed. The results of monolayer depletion and lectin-dependent cellular cytotoxicity assays by LAK cells revealed that the resistance to LAK lysis of IFN-gamma-treated Gl-1 cells is manifested at the stage of LAK cell target recognition alone. We have also divided LAK cells into populations of phenotypically natural killer (NK)- and T-like cells with monoclonal antibodies and complement, respectively. We have used these cells to examine the mechanism of IFN-gamma-induced protection of Gl-1 cells from LAK lysis in cold target inhibition, monolayer depletion, and direct binding assays. The results revealed that NK-like cells do not recognize IFN-gamma-treated Gl-1 cells as efficiently as they do untreated targets, whereas T-like cells show the opposite tendency. In conclusion, we have demonstrated that the IFN-gamma induced protection of tumor cells from LAK lysis is predominantly regulated by the target recognition of NK-like cells. On the other hand, IFN-gamma-treated tumor cells may bind to T-like cells but fail to trigger them to initiate further stages for lysis as effectively as NK-like cells.


Ganglioside composition and its relation to clinical data in brain tumors.

The ganglioside composition of 15 cases of meningioma, 15 cases of astrocytoma, 5 cases of neurinoma, 4 cases of ependymoma, 3 cases of metastatic brain tumor and 1 case each of mixed glioma, oligodendroglioma, medulloblastoma, embryonal carcinoma, and cultured glioma cell line were analyzed by thin-layer chromatography. The GM2, GD3, and GD2 content of the tumors was determined using specific monoclonal antibodies (MAb). Cases were grouped according to the difference in ganglioside pattern and various clinical features. In meningiomas and astrocytomas, GM3 and GD3 were the major gangliosides. The tumor content of the rather simple gangliosides (GM3, GM2, GD3, GD2) increased or was almost equal to that of normal tissue (leptomeninges tissue in the case of meningiomas, and brain tissue in the case of astrocytomas), while the tumor content of complex gangliosides (GM1, GD1a, GT1a, GT1b) decreased as compared with normal tissue. The GM3 content of meningiomas increased in middle-aged patients, who comprised the majority of the patients with these tumors. The GD2 content decreased in middle-aged patients with initial symptoms of meningioma within a year. The GM3 content of astrocytomas decreased in patients who underwent radiotherapy. The amount of GM3 and GD3 increased in small tumors. GM3 may be related to the early proliferative stage. The ganglioside patterns of brain tumors are shown in this study to differ according to clinical features and also to be changeable in their clinical courses.


Effect of leukotriene antagonist on experimental delayed cerebral vasospasm.

Experimental delayed cerebral vasospasm was produced in 16 adult mongrel dogs by the "two-hemorrhage" method of intracisternal injections of autologous arterial blood. Group 1 was a control group. Group 2 was a treatment group that received an intravenous injection of ONO-1078, a novel potent leukotriene antagonist, once a day for 7 days just after the first cisternal injection of the blood. Angiography was performed on Days 0 and 7, and the cerebrospinal fluid levels of leukotriene C4 (LTC4) were measured on Days 0, 3, and 7. The cisternal levels of LTC4 increased after subarachnoid hemorrhage in both groups. But the cerebrospinal fluid levels of LTC4 in the treatment group were significantly lower than those in the control group (P less than 0.05). The angiographic vasospasm after subarachnoid hemorrhage was partially prevented with the treatment of intravenous injections of ONO-1078 (P less than 0.001). These results suggest that LTC4 may play a role in the pathogenesis of delayed cerebral vasospasm, directly or indirectly, and ONO-1078 may have a therapeutic effect on the prevention of the development of delayed cerebral vasospasm.


Successful treatment of intracerebral hydatid cysts with albendazole: case report and review of the literature.

Experience with the use of the drug albendazole in the management of cerebral hydatid disease is limited. We report a 33-year-old woman who was harboring multiple cerebral hydatid cysts and who was treated successfully with albendazole. No other treatment was used. The efficacy and the few reversible side effects of the drug are discussed, and the literature is reviewed.


Continual intracavitary administration of amphotericin B as an adjunct in the treatment of aspergillus brain abscess: case report and review of the literature.

Aspergillus brain abscess is often a fatal disease, regardless of the mode of therapy. Most often seen in the compromised host, it is notoriously refractory to systemic antifungal agents and intrathecal antimycotics. Even with radical surgical debridement, only 13 patients, including the present case, have survived longer than 3 months after being treated for aspergillus brain abscess or granuloma. Studies have shown poor penetration of amphotericin B into the brain and cerebrospinal fluid. One way to achieve therapeutic levels of the agent near the abscess is through the direct introduction of the agent into the abscess site via an indwelling catheter. In the present case, a woman with an aspergillus abscess of the left temporal lobe was treated by a combination of systemic agents, radical debridement, and local therapy, resulting in a cure with a follow-up of 6 years. This is the first reported instance of the use of long-term, local antifungal therapy delivered to the area of the abscess cavity, using a closed reservoir system, and this patient is only the second renal transplant patient reported to have survived aspergillus brain abscess. This form of treatment produced no untoward long-term side effects or neurological sequelae. Local irrigation with antifungal agents should be considered in conjunction with systemic antifungal drugs and drainage and/or debridement in cases of fungal intracerebral aspergilloma. This technique may also prove useful with other fungal brain lesions.


Traumatic subdural hygroma: pathology and meningeal enhancement on magnetic resonance imaging.

Five patients with traumatic subdural hygroma are reported with reference to its pathology and meningeal enhancement on magnetic resonance imaging. Hygromas showed initially iso- and, later, high intensity on both T1- and T2-weighted images compared with the intensity of the cerebrospinal fluid. In all cases of the thick hygromas, magnetic resonance imaging with gadolinium diethylene-triamine-pentaacetic acid showed meningeal enhancement. Intravenously injected radioisotope immediately flowed into the hygromas, but computed tomographic cisternography and gross inspection during the surgery showed no evidence of an influx of cerebrospinal fluid into the hygromas. Microscopic examination of the enhanced meninges revealed vascularized neomembrane with numerous fenestrations and pinocytosis underneath the dura mater. It is suggested from these data that the subdural neomembrane is associated with the development of the traumatic subdural hygromas. Meningeal enhancement would be useful to clarify the growing mechanism of traumatic subdural hygromas.


Cerebral hemorrhage from amyloid angiopathy and coronary thrombolysis.

Coronary thrombolysis with streptokinase or tissue plasminogen activator is useful for the treatment of acute myocardial infarction in selected patients. This treatment is associated with local hemorrhagic complications and age-related cerebral hemorrhage. Coronary thrombolysis is contraindicated in patients with transient cerebral ischemia and stroke, arterial hypertension, cerebral trauma, cerebral aneurysms, and arteriovenous malformations, because of the risk of cerebral hemorrhage. We report the occurrence of a cerebral hemorrhage related to cerebral amyloid angiopathy in a patient who underwent thrombolysis and treatment with heparin for acute myocardial infarction. Despite normal coagulation parameters, the cerebral hematoma enlarged over 36 hours, as documented by sequential computed tomographic scans, to produce significant mass effect, which prompted surgical evacuation. Histological examination of the resected specimen demonstrated the strong affinity for Congo red and yellow-green birefringence that are characteristic of cerebral amyloid angiopathy. Hemostasis was difficult to achieve, as the divided or disrupted amyloid-laden cortical vessels failed to vasoconstrict, their contractile elements replaced by amyloid beta protein. The patient died of recurrent myocardial ischemia 3 days postoperatively. The incidence of cerebral amyloid angiopathy increases with advancing age. It must be considered as a potential source of cerebral hemorrhage in elderly patients undergoing thrombolysis for cardiac ischemia. Such an occurrence presents a difficult challenge because cardiac function is compromised, the coagulation profile may be altered, the cerebral hematoma is life threatening, and intracranial hemostasis is difficult to achieve.


Carotid-cavernous fistula caused by a ruptured intracavernous aneurysm: endovascular treatment by electrothrombosis with detachable coils.

A case of carotid-cavernous fistula caused by a ruptured intracavernous aneurysm is reported. The fistula was treated with electrothrombosis by the detachment of two platinum coils into the aneurysm via an endovascular transvenous approach; the fistula was closed, and the patient has recovered completely. The advantages of using electrodetachable platinum coils include thrombogenicity, controllable deposit, radiopacity, and biocompatibility.


Transcallosal, transventricular approach to a basilar apex aneurysm.

A new approach to the basilar apex in a patient with a megadolichobasilar anomaly and an abnormally rostral basilar apex aneurysm is described. The details of the surgical approach and the advantages and limitations of this transcallosal, interseptal approach are described.


Acoustic neurinoma in the elderly: factors predictive of postoperative outcome.

The authors present the results of acoustic neurinoma surgery in 61 elderly patients (age, > or = 65 years). All the patients were operated upon via the lateral suboccipital approach. Complete tumor removal was achieved in all but two patients. There was no operative mortality. Fifty-seven patients (93%) were independent of nursing assistance at the time of discharge from the hospital. Preservation of the facial nerve was achieved in 95% of the patients, and hearing was preserved in 41%. A risk analysis identified three factors exerting a significant influence on the outcome in these cases: the American Society of Anesthesiology score, the preoperative Karnofsky score, and the size of the tumor. The patients' age was not correlated with the postoperative outcome. These results suggest that, in the majority of elderly patients with acoustic tumors, complete tumor removal can be achieved safely and with minimal postoperative morbidity. Preoperative clinical, neurological, and radiological factors can be helpful in the selection of patients for surgical treatment and may predict postoperative outcome.


Magnetic resonance imaging of tuberculum sellae meningiomas: preventing preoperative misdiagnosis as pituitary macroadenoma.

Despite recent advances in neurodiagnostic imaging, it may be difficult to differentiate tuberculum sellae meningiomas from pituitary macroadenomas preoperatively. Magnetic resonance (MR) imaging has supplanted computed tomography as the imaging modality of choice for sellar and parasellar lesions, but unenhanced MR imaging does not reliably distinguish between all tuberculum sellae meningiomas and pituitary macroadenomas. Accurate differentiation between these alternative diagnoses of a suprasellar mass is important because a tuberculum sellae meningioma always requires a craniotomy, whereas a transsphenoidal route is preferred for removing most pituitary macroadenomas. The gadolinium-enhanced MR images of seven patients with tuberculum sellae meningioma and seven with pituitary macroadenoma were reviewed retrospectively. Although no specific radiological feature was pathognomonic, a combination of several features allowed the correct diagnosis in all cases. Three characteristics of tuberculum sellae meningiomas distinguish them from pituitary macroadenomas: 1) bright homogeneous enhancement with gadolinium, as opposed to heterogeneous, relatively poor enhancement; 2) a suprasellar rather than a sellar epicenter of tumor; and 3) tapered extension of an intracranial dural base. Each of these findings can be subtle, but careful examination of gadolinium-enhanced, high-quality, thin section coronal and sagittal MR images of the parasellar region for this constellation of findings will allow the correct preoperative diagnosis in patients with either of these tumors.


Surgical strategies in the treatment of symptomatic osteomas of the orbital walls.

We present a series of 19 surgically treated osteomas involving the orbital walls. Eight were localized at the junction of the frontal sinus and orbital roof, three were frontoethmoidal, two were of the orbital roof, one of the lateral wall, one of the orbital floor, and four involved all the walls of the orbit and were termed panorbital. All tumors at the junction of the frontal sinus and the orbital roof as well as those originating from the orbital roof proper were removed by frontal craniotomy. In the three that were frontoethmoidal, osteotomies were performed. Lateral and inferior orbitotomies were done when the corresponding orbital walls were affected. The four panorbital osteomas required large frontotemporal craniotomies in association with superolateral orbitotomy and zygomatic and/or malar osteotomy, when necessary. Satisfactory cosmetic and functional results were obtained in all but two cases of panorbital osteomas, in which the neurological deficit worsened after surgery. We discuss the choice of the various approaches described, with reference to the relevant literature.


Treatment and survival of low-grade astrocytoma in adults--1977-1988.

A retrospective review of the records of the Division of Neuropathology at the New York University Medical Center between 1977 and 1988 revealed 53 cases of adult supratentorial astrocytomas. Fifty were fibrillary, and three were gemistocytic. Two additional patients had pilocytic tumors and were not included in the study. The majority of patients had either a subtotal (64%) or gross total resection (19%). Biopsy (17%) was performed for deep-seated lesions and for those lesions confined to eloquent cortex. Forty-eight patients (91%) received postoperative radiation therapy. The median survival was 7 1/4 years with a 5-year survival of 64%. Multivariate regression analysis demonstrated that the most important prognosticators for improved survival were young age, absence of contrast enhancement of the original tumor on computed tomography (CT) and the performance status of the patient. Patients with hemispheric tumors died from dedifferentiation into an anaplastic astrocytoma or a glioblastoma multiforme, with a median time to recurrence of 4.5 years from the original surgery. Survival from the time of recurrence was 12 months. Subsequent operations confirmed progression towards malignancy in six of seven (86%) recurrent tumors. CT contrast enhancement of the original tumor was associated with a 6.8-fold increase in risk for later recurrence. Patients with thalamic tumors (six patients) had a poor prognosis with a median survival of less than 2 years. A review of their CT scans suggest that four died of progressive low-grade disease; however, confirmatory autopsy data were available for only one patient. This study supports others that have shown improved survival for adult patients with astrocytomas treated in the CT era.


Radiotherapy for pediatric brain stem glioma: radiation dose, response, and survival.

An analysis of 39 patients under 20 years of age with brain stem glioma treated with radiotherapy between 1977 and 1991 was undertaken. Twenty-eight (71.2%) of the patients responded well to initial radiotherapy, and 11 (28.8%) responded poorly. Median survival for the total patient population was 10 months. Response rates and median survivals were influenced by radiation dose: 45.5% and 9 months at doses less than 4499 cGy (n = 11), 83.3% and 13 months at doses between 4500 and 5499 cGy (n = 12), 66.7% and 11.5 months at doses between 5500 and 6499 cGy (n = 9), and 100% and 10 months at doses more than 6500 cGy (n = 7). Multivariate analysis revealed the response to initial radiotherapy was the only predictor of survival with radiation doses up to 6499 cGy. Four of the patients who responded well demonstrated radiological and/or histological calcification within or around the tumor at the time of clinical deterioration. Radiation injury was confirmed in two autopsy cases. The possibility that intratumoral radiation injury causes clinical deterioration is suggested.


Pathological status of the mesial temporal lobe predicts memory outcome from left anterior temporal lobectomy.

This investigation tested the hypothesis that the degree of impairment to memory function caused by an anterior temporal lobectomy (ATL) is inversely related to the pathological status of the resected hippocampus. Specifically, the greatest risk to postoperative memory function should be to patients with no or minimal hippocampal sclerosis, i.e., those with a functional hippocampus. Forty patients who underwent a partial resection of the left (n = 21) or right (n = 19) anterior temporal lobe were administered tests of immediate and delayed verbal and figural memory, both preoperatively and 6 months postoperatively. The degree of postoperative impairment in memory function was then investigated as a function of the degree of hippocampal sclerosis, as determined by a standardized procedure. For a left ATL, an absence or mild degree of hippocampal sclerosis was associated with significantly greater postoperative impairment of both verbal and figural memory, compared with patients with moderate or marked sclerosis. No statistically significant relationship was noted for patients who underwent a right ATL, but the findings were in the same direction for five of six memory measures. It may be possible to predict and avoid surgically induced impairment of memory function among patients who undergo left ATL through the use of preoperative hippocampal volumetric magnetic resonance imaging. Better clinical tests of right hippocampal function are needed to predict the outcome for patients who undergo a right ATL.


Cerebral vasodilation after the thermocoagulation of the trigeminal ganglion in humans.

The resulting changes in the regional cerebral blood flow of 18 patients suffering from idiopathic trigeminal neuralgia and treated by selective thermocoagulation of the trigeminal ganglion were measured by xenon-133 emission tomography. One hour after thermal stimulation, there was an asymmetric increase (P < 0.05) in cerebral blood flow, with a 14.7% mean increase in the ipsilateral cerebral hemisphere (P < 0.001) and a 12.7% mean increase in the contralateral side (P < 0.01). The increase in regional cerebral blood flow was not uniform but was most marked in the ipsilateral middle cerebral artery territory (P < 0.001). There was a slight decrease in cerebellar blood flow, but the reduction in the ipsilateral cerebellar lobe was less than that in the contralateral lobe (P < 0.01). The topography of the most significant changes coincided with that of the innervation of the cerebral vessels by the trigeminal nerve. Several mechanisms are involved in the increase in regional cerebral blood flow, including overall nonspecific activation of the central nervous system and local mechanisms associated with the trigeminal-vascular system.


Changes in human intracerebral temperature in response to different methods of brain cooling.

The rectal, epidural, and intraventricular temperatures were continuously monitored in 10 seriously injured and unconscious patients admitted for neurosurgical intensive care. Different attempts were made to lower their brain temperatures. Isolated head cooling, whether with frozen liquid (Hypotherm Gel Kap; Flexoversal, Hilden, Germany) or a cooling helmet, had very limited effect. Nasopharyngeal cooling had no effect. During barbiturate coma, a considerable increase in brain temperature was observed. The administration of paracetamol was the single most effective method by which to lower brain temperature, at times by 2 degrees C and usually with a concomitant decrease in the temperature gradient between the rectum and the brain. However, in order to achieve a lasting reduction of brain temperature to 35 degrees C, we had to use a combination of head cooling and intensive whole-body cooling.


Intraventricular hemorrhage in blunt head trauma: an analysis of 43 cases.

Before the advent of computed tomography, intraventricular hemorrhage (IVH) from any source was thought rare and invariably fatal. Although intraventricular blood is readily identifiable with computed tomography, there has been little systematic study of its significance in blunt head trauma. Forty-three patients with traumatic IVH were prospectively identified in 1 year at Harborview Medical Center (University of Washington). Most were victims of motor vehicle accidents and suffered severe head injuries. IVH occurred alone in two patients; superficial contusions and subarachnoid hemorrhage were the most common associated finding. Blood was present in only one or both lateral ventricles in 25 patients; only the 3rd or 4th ventricles in 4 and all ventricles in 14 instances. There were 3 intracerebral hematomas and 14 basal ganglion hemorrhages. All of the former and half of the latter communicated with the adjacent lateral ventricle. Extra-axial hematomas appeared more common when only the lateral ventricles were involved, whereas corpus callosum or brain-stem hemorrhage appeared more likely when all the ventricles were involved. Acute hydrocephalus was rare, and ventricular drainage was needed in only four cases. Intracranial pressure (ICP) was elevated (> 15 mm Hg) in 46% of patients. The amount of IVH was related inversely with the Glasgow Coma Scale, but not with increased ICP. The presence of IVH indicated a poor outcome, with only half of the patients being independent at a 6-month follow-up. Poor outcome was associated with increasing age, low admission Glasgow Coma Scale, the presence of space occupying lesions if only the lateral ventricles were involved, and hemorrhage in all four ventricles.(ABSTRACT TRUNCATED AT 250 WORDS)


Effect of nicardipine on basilar artery vasoactive responses after subarachnoid hemorrhage.

The effect of the dihydropyridine calcium antagonist, nicardipine, on the vasoactive responses of the basilar artery was investigated after subarachnoid hemorrhage (SAH). Forty-five rabbits were separated into one control group and four groups receiving SAH (nine animals each). The SAH was induced by injecting 5 ml of autologous arterial blood into the cisterna magna. SAH animals were subjected to one of the following: 1) no treatment; 2) intravenous (i.v.) saline infusion (vehicle); 3) i.v. infusion of low-dose nicardipine (0.01 mg/kg/hr), or 4) i.v. infusion of high-dose nicardipine (0.15 mg/kg/hr). The i.v. infusions were started immediately after SAH and continued for 48 hours. Serotonin (5-HT) (10(-8) to 10(-5) mol/L) was used to evoke dose-dependent vasoconstriction of isolated rings of the basilar artery 2 days after SAH. Acetylcholine (ACh) (10(-8) to 10(-4)) and adenosine-triphosphate (ATP) (10(-8) to 10(-4) mol/L) were applied after maximal contraction with 5-HT, evoke a dose-dependent vasodilatation. Compared with controls, in animals subjected to SAH serotonin caused similar or slightly larger contractions; nicardipine infusion did not decrease the amount of contraction observed after SAH. ACh and ATP caused significantly less dilatation in animals submitted to SAH than in controls. After high-dose nicardipine, ACh- and ATP-induced dilatations were significantly more pronounced (57% and 68% of initial contractile tone) than in the other animals receiving SAH (36%-39% and 45%-55%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)


Experimental aspects of cerebrospinal hemodynamics: the relationship between blood flow velocity waveform and cerebral autoregulation.

The dynamic relationships among mean flow velocity, its pulsatile amplitude (FVa), cortical cerebral blood flow (CBF), and cerebral perfusion pressure (CPP) were studied in normal rabbits and rabbits with subarachnoid hemorrhage using 8-MHz pulsed transcranial Doppler ultrasound and hydrogen clearance under conditions of systemic hypotension and intracranial hypertension. A two-slope relationship was observed between FVa and CPP with a break point that correlated closely with the lower limit of CBF autoregulation in each animal. Below this CPP break point, FVa varied directly with CPP, and above the break point FVa varied inversely with CPP. In this experimental model, an inverse correlation between FVa and CPP indicates intact CBF autoregulation, whereas loss of that correlation implies exhaustion of autoregulatory reserve. Simultaneous recording and computation of FVa, CPP, and the correlation coefficient between FVa and CPP may be a means of monitoring CBF autoregulation in clinical practice.


Relation between protein kinase C and calmodulin systems in cerebrovascular contraction: investigation of the pathogenesis of vasospasm after subarachnoid hemorrhage.

The protein kinase C (PKC) and calmodulin systems each play a role in vascular contraction. However, the correlation of these two systems in producing contraction has been unclear. To clarify the pathophysiology of vasospasm after subarachnoid hemorrhage, the authors demonstrated tonic contraction of the cerebral artery in a study of isometric tension, and investigated the correlation of the PKC and calmodulin systems in producing the contraction. To develop better management for vasospasm, they also examined the effect of calmodulin antagonists on tonic contraction. The development of isometric tension in canine basilar arteries was measured, with the following results: 1) tonic contraction was dependent on the PKC system, but initiation of the contraction by the calmodulin system was necessary for the subsequent PKC-dependent tonic contraction; 2) specific calmodulin antagonists like chlorpromazine and pimozide partially inhibited the tonic contraction associated with PKC activation; 3) another calmodulin antagonist, trifluoperazine, inhibited the PKC system as well. On the basis of these results, the authors conclude that the PKC system plays a role in the development of vasospasm. In the early phase of contraction, the calmodulin system contributes to the subsequent fully-activated, PKC-induced tonic contraction. To manage vasospasm, a specific calmodulin antagonist would therefore not be sufficient. Suppression of both the calmodulin and PKC systems with trifluoperazine in the earliest stage of vasospasm is recommended.


Protein kinase C activity correlates with the growth rate of malignant gliomas: Part II. Effects of glioma mitogens and modulators of protein kinase C.

The proliferation rates of gliomas may be modulated by the protein kinase C (PKC) signal transduction system. The present study was undertaken to further examine the role of PKC system in growth regulation of gliomas in vitro by measurement of PKC activity over various phases of tumor growth and by assessing its potential role as a signal transduction system induced by serum mitogens and the known glioma mitogens epidermal growth factor and fibroblast growth factor. All human glioma lines examined, and the rat glioma C6, displayed high PKC activity relative to nonmalignant glial cells, which correlated with their proliferation rates over their respective growth phase. Frozen surgical human malignant glioma specimens also displayed high PKC activity. The relatively selective PKC inhibitor staurosporine (SP) reduced PKC activity and corresponding growth rates in a dose-related manner. Stimulation of PKC with phorbol esters under different concentrations of serum in the growth medium indicated that the high PKC activity, which correlated with their rapid growth rates, is highly susceptible to down-regulation by these agents. Epidermal growth factor and fibroblast growth factor increased both PKC activity and the growth rate of glioma line A172; addition of SP reduced the growth rate to levels observed in SP-treated control tumors, indicating that PKC may be a common signal transduction system induced by these mitogens. These results implicate PKC as an important signal transduction system regulating glioma growth, and offers a potential target for tumor inhibition.


Enhancement of radiosensitivity by tamoxifen in C6 glioma cells.

The antiestrogen drug tamoxifen, which is used extensively in the treatment of breast cancer, has also been reported to inhibit the proliferation of some estrogen receptor-negative cell lines, including malignant glioma in vitro. To explore the possible role of tamoxifen in the treatment of malignant glioma, we have investigated its effects on cell growth and radiosensitivity in C6 glioma cells using a colony-forming assay and a tetrazolium-formazan growth rate assay. Pretreatment of C6 cells with tamoxifen resulted in dose-dependent inhibition of cell growth and enhancement of the antitumor effects of ACNU and irradiation. The radiosensitivity of the treated cells was enhanced by the administration of 5 mumol/L of tamoxifen either before and during irradiation or continuously before, during, and after irradiation [37% survival dose (Do) = 2.68 +/- 0.19 and 2.64 +/- 0.04 Gy, respectively, P < 0.01)], as compared with controls (Do = 3.79 +/- 0.25 Gy). In addition, protein kinase C activity was also inhibited by tamoxifen at the concentration in which the radiosensitivity was augmented in C6 cells. Taken together, our results demonstrate a synergistic effect of tamoxifen with radiation on intracellular damage in C6 glioma cells, which may in part be due to the inhibition of protein kinase C, suggesting that tamoxifen serves as a useful agent in combination therapy of glioma.


Measurement of local directional pressures in the brain with mass.

In order to understand the effects and the direction of pressure transmitted from a mass lesion through various brain structures, miniature strain gauges were inserted in different brain locations in eight anesthetized monkeys. Mass lesions were created by inflating a balloon in either of two locations--subcortical in four animals (Group I) and deep (lateral to the caudate nucleus) in the other four animals (Group II). Anterior-posterior directed pressures were thus measured from a gauge placed in the parietal lobe, and lateromedially directed pressures (LM-dPs) were measured from gauges in the temporal lobe and midbrain. Intracranial pressure, systemic mean arterial pressure, and cerebral blood flow were also monitored. After balloon inflation was begun, temporal changes in pressure were recorded from gauges as percentage increase or decrease from baseline measurements. In both groups, balloon inflation caused a gradual increase in the parietal lobe anterior-posterior directed pressure with a concomitant increase in intracranial pressure and a decrease in cerebral blood flow. The temporal lobe gauge in Group I recorded an initial negative followed by a positive LM-dP with further balloon inflation. In Group II, this gauge recorded a positive LM-dP throughout. The midbrain gauges in both groups recorded an initial positive followed by a negative LM-dP. This reversal in the direction of pressure in the midbrain occurred just before the supratentorial pressure reached a peak and was noted to be concurrent with a sudden rise in mean arterial pressure and a decline in cerebral blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)


Hemorrhage in a highly vascularized subependymoma of the septum pellucidum: case report.

A 63-year-old man was admitted to our hospital because of loss of memory, disorientation, nausea, and urinary incontinence. Cerebral computed tomographic and magnetic resonance imaging scans revealed a tumor with intratumoral hemorrhage affecting the corpus callosum and the septum pellucidum. A partial resection of the tumor was performed, but the patient died the next day from an episode of bleeding. Postmortem examination revealed a highly vascularized subependymoma with acute bleeding in the tumor and in the surrounding brain parenchyma. The importance of considering a highly vascularized subependymoma is noted when a tumor related to the ventricular system is diagnosed.


Anterior third ventricle meningioma in an adolescent: a case report.

A case of an anterior third ventricular meningioma in a 17-year-old girl is presented. Gross total resection of this tumor with minimal morbidity was accomplished by transcallosal exposure through a frontal craniotomy. A review of the literature implies that surgical morbidity and mortality for the removal of third ventricular meningiomas markedly improved with the use of the operating microscope. Despite advanced imaging capabilities, radiographic analysis of a solid third ventricular mass may not always determine tissue diagnosis. In addition, preoperative placement of a ventriculoperitoneal shunt will treat hydrocephalus, but may limit the surgical options for tumor exposure. The differential diagnosis for this solid anterior third ventricular mass is presented, and the method of treatment for this case is discussed.


Suprasellar granular cell tumor.

A case of a suprasellar granular cell tumor, approximately 1.5 cm in diameter, in a 68-year-old woman is described. Diagnosis was established postoperatively by histopathological examination of the tumor tissue. The preoperative computed tomographic scan revealed a slightly hyperdense suprasellar mass with strong contrast enhancement. There was no evidence of calcification. The T1-weighted image on magnetic resonance imaging scan showed an isointense tumor with non-homogeneous enhancement after intravenous gadolinium diethylene-triamine-pentaacetic acid. In the proton-weighted image, the suprasellar mass presented a non-homogeneously enhanced signal. A non-homogeneous signal reduction was seen in the T2-weighted image.


Solitary eosinophilic granuloma invading the clivus of an adult: case report.

A 41-year-old white man with facial pain and diplopia was found to have an invasive lesion of the clivus. The final pathological diagnosis was eosinophilic granuloma. The patient's symptoms resolved completely after transsphenoidal resection of the lesion. The pathological and radiological diagnosis and the treatment of solitary eosinophilic granulomas are discussed.


Spinal epidural angiolipoma: rare or unreported?

Three cases of spinal epidural angiolipoma, all affecting middle-aged women, are reported. Spinal epidural angiolipomas are considered a separate entity from the more common lipomas involving the same space. Although these tumors are considered very rare, the occurrence of three cases in less than 2 years in the same geographical area raises the question of their frequency. The computed tomographic scan has been misleading in two of our patients, whereas magnetic resonance imaging was highly suggestive. Two of these tumors were apparently exceptional, being lumbar and anterior. The patients were admitted with typical sciatic symptoms; one tumor eroded the vertebral body. Spinal epidural angiolipomas may go unreported because their pathogenetic potential is not fully recognized. We suggest that both magnetic resonance imaging and the operating microscope should have a more significant place in the evaluation and treatment of sciatica.


"Dolichoectatic" intracranial vertebrobasilar dissecting aneurysm.

We report five patients with intracranial vertebrobasilar dissecting aneurysms, all of whom had ischemic symptoms. Angiographically, four of the five cases revealed distention and elongation of the vertebrobasilar artery like dolichoectasia and one irregular stenosis, the so-called "string sign". Magnetic resonance imaging disclosed all dolichoectatic dissecting lesions by demonstrating intimal flaps, double lumen, or subacute clot in the false lumen. We also present a successful demonstration of slow flow in the false lumen by gradient refocused magnetic resonance imaging scan with partial flip angle by the cardiac gating method. It is suggested that many of the classical "dolichoectasia" may include dissecting lesions.


Carotid cavernous fistula and false aneurysm of the cavernous carotid artery: complications of transsphenoidal surgery.

Injury to the cavernous internal carotid artery is an unusual and serious complication of transsphenoidal surgery. Two such patients with injury to the carotid artery, referred for endovascular treatment, are reported. The clinical course and successful treatment of these patients, one with an intracavernous false aneurysm and one with a carotid cavernous fistula, are described. A review of these vascular complications of transsphenoidal surgery is presented.


Cerebral arteriovenous malformations in a pregnancy with twins: case report.

The natural course of cerebral arteriovenous malformations during pregnancy is not well known. An inoperable cerebral arteriovenous malformation was diagnosed by angiography, computed tomography, and magnetic resonance imaging before pregnancy and followed by magnetic resonance imaging during pregnancy. No significant changes were detected in the size of the cerebral arteriovenous malformation during pregnancy, and healthy twins were born by cesarean section.


Acute bilateral ophthalmoplegia secondary to cavernous sinus metastasis: a case report.

A case of a 60-year-old man with metastatic adenocarcinoma of the colon who developed bilateral ophthalmoplegia acutely is presented. Bilateral cavernous sinus metastasis was suggested by magnetic resonance imaging and proven by endoscopic sphenoidal biopsy. The patient was treated with radiotherapy (2000 cGy) with near resolution of his symptoms. This patient represents the first reported case of acute bilateral ophthalmoplegia resulting from hematogenous metastasis to both cavernous sinuses, diagnosed antemortem. A review of the more common causes of acute bilateral ophthalmoplegia is presented.


Bilateral homonymous hemianopsia due to tentorial herniation, with sparing of central vision: case report.

Cases of complete bilateral homonymous hemianopsia with sparing of central vision that are caused by bilateral tentorial herniation are extremely rare. We describe one such case resulting from severe head trauma, the first to be reported in which magnetic resonance images showed clear evidence of the responsible lesion. The causes of bilateral homonymous hemianopsia with sparing of central vision and the possible mechanisms whereby macular sparing may arise are discussed.


Positron emission tomography-guided stereotactic brain biopsy.

We describe a technique that allows target definition for stereotactic brain biopsy using coordinates calculated on stereotactic positron emission tomographic (PET) images. In this study, PET images were obtained using [18F]-labeled fluorodeoxyglucose, a marker for glucose metabolism. The difference between PET-calculated and actual stereotactic coordinates of simulated targets is within PET spatial resolution. Combined computed tomography- and PET-guided stereotactic biopsies were performed in 11 patients with brain tumors. In this report, we describe two representative patients who underwent stereotactic brain biopsy using the present technique. Because of the complementary role of PET and computed tomography, their integration in multimodality planning might optimize the target selection for stereotactic brain biopsies.


Ultrasonographic and electrophysiological adjuncts to surgery within the brain stem: technical note.

The surgical approach to intrinsic lesions within the brain stem is undertaken by the surgeon knowing the potential for significant operative morbidity. We report the use of real-time intraoperative ultrasound and electrophysiological mapping techniques to aid in the localization and resection of an intrinsic brain-stem tumor in a child. These techniques permitted an aggressive surgical approach without encountering adverse postoperative neurological sequelae.


Effect of plasma from premenstrual syndrome and control patients on human platelet and rat brain synaptosome monoamine oxidase B activity.

The present study determined the kinetic properties of platelet monoamine oxidase (MAO) in patients with premenstrual syndrome (PMS) and control subjects during the pre- and postmenstrual intervals. In addition, we investigated the effects of plasma obtained during the pre- and postmenstrual intervals from both subject groups on MAO activity in washed human platelets and rat brain synaptosomes. The Vmax of platelet MAO in postmenstrual PMS patients was significantly less than that during the premenstrual phase. Plasma from both subject groups (10-100 microliters) inhibited platelet and synaptosomal MAO in a dose-dependent manner to approximately the same degree at each time interval. The results indicate that although human plasma contains endogenous substances which inhibit MAO activity, alterations in their concentration are probably not responsible for the previously reported transient changes in platelet MAO activity in PMS.


Electroconvulsive therapy-induced cortisol release after dexamethasone in depression.

ECT-induced cortisol release was distinctly seen, and fell along a course of ECT in each of 12 inpatient male melancholics (p = 0.00024, binomial), with dexamethasone given to diminish the elevated baseline cortisol levels typically seen in depression. Cortisol release dropped on average by 55% (p = 0.015), from 16.6 +/- 6.8 micrograms/dl (p = 0.000002) with the first ECT to 8.0 +/- 7.7 micrograms/dl (p = 0.000003) after 6 or more ECTs. The fall along the course was larger with unilateral ECT than bilateral ECT (p = 0.042), although significant regardless of electrode placement, suggesting that unilateral ECT tends to lose therapeutic impact along a course in comparison to bilateral ECT.


Residual effects of repeated administration of triazolam and nitrazepam in healthy volunteers.

The residual effects of hypnotics were investigated with a long-acting (nitrazepam) and a short-acting (triazolam) benzodiazepine hypnotic in 8 male volunteers. Subjects received placebo, nitrazepam 5 mg, or triazolam 0.25 mg for 7 consecutive nights in a random-order, double-blind crossover design. Daytime sleepiness, psychomotor performance, EEG activity and standing steadiness were assessed in the morning after 1, 4, and 7 days of drug treatment. Plasma concentrations of nitrazepam and triazolam were also assayed. The concentration of nitrazepam increased gradually during the course of treatment and was associated with residual sedative effects on days 4 and 7. Nitrazepam produced no apparent psychomotor impairments in these studies. On the other hand, there was no evidence of drug accumulation after triazolam administration and triazolam showed no residual sedative effects or residual impairment of psychomotor performance during the experiment. Thus, short-acting hypnotics may have an advantage over long-acting hypnotics in terms of producing less residual sedative effects during chronic treatment.


Clinical safety and efficacy of tianeptine in 1,858 depressed patients treated in general practice.

1,927 outpatients were included by 392 general practitioners in an open study in order to evaluate the safety of tianeptine in the ambulatory treatment of depression. The results of 1,858 depressed patients without melancholia and psychotic features, fulfilling DSM III criteria of Major Depressive Episode or Dysthymic Disorder, could be analysed. 1,458 patients completed the 3-month treatment period. The group treated with 37.5 mg/day of tianeptine showed improvement on the Montgomery-Asberg Depression Rating Scale. With regard to the clinical tolerance of tianeptine, somatic complaints were rarely reported and adverse events necessitating premature termination of treatment (4.8% of included patients) were without clinical severity. Cardiovascular, haematologic, hepatic and biochemical safety were verified. No signs of dependence and no specific withdrawal symptoms were found after discontinuation of treatment.


Selective effects of colds and influenza on human performance efficiency: a critical appraisal.

This paper provides an appraisal of the results published from the MRC Common Cold Unit on human performance efficiency during minor upper respiratory tract infection, i.e., colds and influenza. Despite strict controls employed in the methods of data collection, the robustness of the results and some of the conclusions drawn are questioned. In particular, the claim that colds and influenza lead to selective (and different) effects is criticised as being based on incomplete data. The lack of replication, the small sample sizes, possible response biases and use of controls are considered. Overall, it is argued that there are insufficient data to provide conclusive evidence for selective effects and that over-generalisation from such studies can be misleading.


Cognitive and psychomotor function during severe insulin-induced hypoglycaemia in insulin-dependent diabetic patients.

Cognitive and psychomotor function, hormonal counterregulation and symptom awareness during severe insulin-induced hypoglycaemia were evaluated in 10 insulin-dependent diabetic patients. The glucose-clamp technique (Biostator) was applied to achieve a stable hypoglycaemic (39 +/- 2 mg/dl) plateau. A battery of 7 neuropsychological tests and a standardized questionnaire assessing hypoglycaemia symptoms were administered during euglycaemia and hypoglycaemia. There was a significant increase in counterregulatory hormone response (cortisol, growth hormone, p less than 0.05). Every patient experienced symptoms during severe hypoglycaemia. Four patients, however, were not aware of this threatening metabolic state. There was a significant performance decrement in all but two neuropsychological tests (Aiming Center I, Aiming Center II, Line Tracing Errors, Reaction Time, p less than 0.01; Digit Symbol, p less than 0.05). Performance of simple motor tasks as well as cognitive tasks requiring complex discrimination deteriorated similarly. Furthermore, the patients' general well-being (subjective condition) worsened considerably. In conclusion, a significant impairment of neuropsychological functions emerged during severe hypoglycaemia in insulin-dependent diabetes mellitus, even in the face of adequate hormonal counterregulation, and did not always coincide with an appropriate patient awareness of the actual metabolic state.


Effects of age on event-related potentials in chronic alcoholics: a multimodal study.

To test different versions of the premature aging hypothesis in alcoholics, brainstem auditory evoked potentials (BAEPs), long-latency auditory evoked potentials (LAEPs), P3 and visual evoked potentials (VEPs) were recorded in 32 alcoholic subjects. The phenomena in patients' event-related potentials (ERPs) differ from those observed in normal aging subjects and become more pronounced with age. ANOVA showed a significant effect by group (alcoholic patients/controls) on certain parameters of BAEPs (III, III-V, I-V), VEPs (P100 latency) and LAEPs (N1-P2 amplitude and N2 latency) unaffected by age, while age had a significant effect on some parameters of LAEPs (N2-P3 amplitude, P3 latency) unaffected, or less affected by chronic alcohol consumption. At a clinical level, abnormalities in BAEPs and VEPs seem good early trouble indices in alcoholic patients, while alterations in latencies and amplitudes of LAEPs appear in older patients. These data seem to be in favor of a critical age or critical abuse in the action of alcohol, in place of the classical hypothesis of premature aging.


Strange attractors, chaotic behavior and informational aspects of sleep EEG data.

In order to perform a nonlinear dimensional analysis of the sleep EEG, we applied an algorithm proposed to calculate the correlation dimension D2 of different sleep stages. D2 characterizes the dynamics of the sleep EEG, estimates the degrees of freedom, and describes the complexity of the signal under study. An attempt is made to correlate dimensionality analysis and informational aspects of the sleep EEG. Information processing by the brain during different sleep stages of healthy subjects under the influence of lorazepam and in unmedicated acute schizophrenics is estimated.


Componential analysis of problem-solving ability: performance of patients with frontal lobe damage and amnesic patients on a new sorting test.

A new sorting task designed to isolate and measure specific components of problem-solving ability was administered to four subject groups: patients with focal frontal lobe lesions, patients with both frontal dysfunction and amnesia (Korsakoff's syndrome), patients with circumscribed (non-Korsakoff) amnesia, and normal control subjects. The patients with circumscribed (non-Korsakoff) amnesia, and normal control subjects. The patients with frontal lobe lesions and patients with Korsakoff's syndrome were impaired on eight of the nine components of the task. The findings run counter to theories of a single or primary impairment in patients with frontal lobe dysfunction. Rather, the results suggest that a wide spectrum of deficits in abstract thinking, cognitive flexibility, and use of knowledge to regulate behavior contributes to the problem-solving impairment of these patients. Although the (non-Korsakoff) amnesic patients performed similarly to normal subjects on most measures, a finer analysis suggested that successful performance on this complex sorting task, in addition to being strongly dependent upon frontal lobe function, is mildly dependent upon memory function.


Letter matching in the hemispheres: speed-accuracy trade-offs.

Eight subjects performed physical and nominal letter-matching tasks for pairs of letters presented in the left, right, or central visual fields, using a unimanual two-choice response-time paradigm. Latencies were manipulated by using a cued response procedure, and speed-sensitivity and speed-bias functions were calculated separately for each of the peripheral visual field by response hand conditions. Hemispheric contributions to these tasks were investigated by looking for evidence of exclusive specialization and callosal transfer. The results suggest that both hemispheres are able to perform the tasks and that they do so using similar processing strategies, but they differ in the response-choice stage of the nominal identity task.


Troubled reaching after right occipito-temporal damage.

We encountered a man with an unusual reaching disturbance due to a stroke in the right occipito-temporal cortex and subjacent white matter. We studied his behavior in detail including vision and hand control. He had a left homonymous hemianopia. In his remaining fields static visual acuity and stereoacuity were normal, but he could not detect a coherent motion signal or follow moving targets with smooth pursuit. Transduction of limb movements using an optoelectronic technique showed abnormal morphology, increased variability and markedly prolonged latencies for transport to external visual targets, yet he achieved these targets with precision. Reaching to self-bound targets, and to the remembered locations of external targets with vision blocked was 5 x faster. The findings may be explained by: (1) damage in regions homologous to areas TF and TH in the monkey, which provide visual inputs to hand and forelimb representations in the cortex; (2) injury in human regions homologous to the monkey's MT complex, with inability to use visual information on the movement of the limb due to a visual motion processing defect; and (3) disruption of visual cortical-subcortical connections mediating crucial transformations among limb and target representations.


Revisiting the oddball paradigm. Non-target vs neutral stimuli and the evaluation of ERP attentional effects.

We recorded topographic mapping of auditory evoked potentials (AEPs) to homogeneous series of tones delivered in the absence of any cognitive task ("neutral condition") and compared them with responses to identical stimuli when they acted as non-targets in an oddball paradigm. With respect to the neutral condition, non-target responses showed an increase in N100 amplitude which was found to depend on two different, but partially overlapping effects. The "early effect" had similar latency and topography as exogenous N100 and may reflect changes in the overall state of alertness since its amplitude declined at the end of the test. The "late effect" affected the N100s descending slope and had features consistent with those of a processing negativity. It was frontally distributed, and topographic mapping revealed a right-sided predominance. Finally, non-target responses exhibited a central positivity (P250) which did not appear in neutral AEPs. P250 shares several features, including latency, amplitude and scalp topography, with the endogenous ERP component commonly labelled "P3a". Non-target P250 could be the result of an attentional shift towards the stimuli, and reflect some aspects of the classification process. We suggest that non-target responses in simple oddball paradigms should be routinely studied along with target responses in order to improve the diagnostic capabilities of cognitive ERPs. Notably, non-target responses may help to decide whether an abnormal target-P300 is related or not to a deficit in the mobilization of attentional resources.


Orienting of auditory spatial attention: effects of a lateralized tone cue.

Mondor and Bryden [8] (Neuropsychologia 29, 1179-1190, 1991) reported that the normal Right Ear Advantage for the identification of verbal material presented dichotically could be largely eliminated if subjects were cued to attend to and report from only one ear on each trial. In these experiments, the ear to be attended was cued by presentation of a tone to that ear only prior to each dichotic trial. The present series of studies were undertaken to determine whether this lateralized tone cue exerted its effect by orienting attention or by alerting the subject of the forthcoming trial. Results revealed that for both the right and left ears the facilitating effect of the cue was dependent on the accuracy of the location information it conveyed. Thus, the precueing technique originally employed by Mondor and Bryden as a means of controlling the contribution of attention to ear advantages was validated. It is concluded that the precueing technique provides a powerful means for specification of the extent to which attentional factors and hemispheric functional capabilities contribute to ear asymmetries.


Direction of lateral eye movements as an index of cognitive mode and emotion: a reappraisal.

Three experiments were designed to determine the effects of cognitive and emotional questions on subjective ratings, lateral eye movement (LEM) incidence and LEM direction. Although the cognitive content of questions affected subjective ratings and the incidence of LEMs, emotional content had an effect only on subjective ratings. Neither cognitive nor emotional content influenced LEM direction. The results raise doubts about the sensitivity of LEM direction as an index of lateralized cerebral processing.


Right hemisphere advantage for social recognition in the chick.

Recognition of familiar and unfamiliar conspecifics was studied in pair-reared chicks tested binocularly or with only one eye in use. Chicks were tested on day 3 in pairs composed of either cagemates or strangers. Social discrimination, as measured by the ratio "number of pecks at the strangers/total number of pecks" was impaired in right-eyed chicks with respect to left-eyed and binocular chicks. Male chicks showed higher levels of social pecking than females, and chicks that used both eyes showed higher pecking than monocular chicks. There were no significant differences in the total number of pecks (i.e. pecks at companions plus pecks at strangers) between right- and left-eyed chicks: the impairment in social discrimination of right-eyed chicks seemed to be due partly to a reduction in pecking at strangers and partly to an increase in pecking at companions. It is suggested that neural structures fed by the left eye (mainly located at the right hemisphere) are better at processing and/or storing of visual information which allows recognition of individual conspecifics. This may be part of a wider tendency to respond to small changes in any of a variety of intrinsic stimulus properties.


A comparison of normal old rats and young adult rats with lesions to the hippocampus or prefrontal cortex on a test of matching-to-sample.

Rats with lesions to the dorsal hippocampus (HPC) or prefrontal cortex (PFC), normal old rats, and young adult controls were compared on a test of matching-to-sample. Subjects were presented with two lights in succession and were trained to press a lever when the lights were the same brightness and withhold a lever-press when they were different. The PFC and aged groups, but not the HPC group, were impaired when the comparison stimulus was presented immediately after the sample stimulus. When delays of 5 and 15 sec were introduced between the stimuli, the HPC and aged groups' performance deteriorated to chance levels. The PFC group's performance was not differentially affected by the delays. The results were consistent with previous findings that implicated the HPC in episodic memory and the PFC in working memory. The aged group was impaired on both types of memory, revealing signs of HPC and PFC dysfunction.


Perception of optical flow in cortical blindness: a case report.

Motion perception was studied in a subject with bilateral lesion of the visual cortex, involving severe damage to cortical areas V1 and V4, but with no apparent damage to visual associative areas situated in occipito-parietal and lateral occipito-temporal (presumably V5) zones. He was able to perceive optical flow motions simulating motion in depth in "blind" parts of his visual field, provided that the stimulus-onset was temporally dissociated from its motion. Moreover, he was able to discriminate between different velocities and directions of motion. The results suggest that perimetrically "blind" parts of the visual field in this patient have true capacities to process visual motion. They are discussed in reference to the subject's ability to move freely in his environment and in reference to the role of extrastriate visual pathways in visual motion processing.


Pseudoneglect and reversed pseudoneglect among left-handers and right-handers.

Two experiments were carried out to examine specific hand contribution to pseudoneglect and reversed pseudoneglect phenomena in dextrals and sinistrals when bisection tasks were conducted exclusively in the midline spatial condition. Both dextrals and sinistrals showed the same overall pattern deviation: in the tactile scanning task, both right and left hands deviated to the left of the midpoint and in the kinesthetic scanning tasks, the right hand deviated to the left and the left hand to the right of the midpoint. However, when these deviations were tested against zero (i.e. the objective midpoint) clear differences appeared related to hand, task and handedness. These results were discussed with respect to "enhancement theory".


Cognitive flexibility and mental programming after closed head injuries and anterior or posterior cerebral excisions.

Cognitive inflexibility and deficient mental programming are specifically related to frontal lobe lesions. The aim was to demonstrate that closed head injury (CHI) patients with brain lesions verified by computed tomography have such cognitive deficits, and are inferior in these respects to patients with posterior cerebral excisions mainly for tumours. This hypothesis was confirmed using a Category Identification and Sorting test as well as a measure of mental programming in a Spatial Learning task. Furthermore, CHI patients who had non-frontal parenchymal lesions were inferior by these measures to patients with posterior excisions. This result suggests that diffuse axonal lesion in CHI causes the deficits similar to those following frontal lobe excision.


Learning and retention of melodic and verbal information after unilateral temporal lobectomy.

The role of the temporal lobes in auditory memory was tested in two analogous tasks assessing learning and 24-hr delayed recognition of unfamiliar melodies and nonsense words. The performance of patients with either anterior right (RT) or left (LT) temporal lobectomy was impaired in learning and delayed recognition of both melodies and words, as compared to normal control subjects, although some preserved learning over successive trials was observed. These results suggest a bilateral temporal-lobe contribution to the learning of these auditory patterns. However, melodies and nonsense words were not recognized in the same way by the two patient groups after 24 hr: subjects in the LT group tended to improve on melodies but drop on words, whereas subjects with RT lesions displayed the reverse pattern, suggesting a differential role for each temporal lobe in long-term memory, according to the nature of the cues inherent to a given type of stimulus.


Right hemisphere specialization for the identification of emotional words and sentences: evidence from stroke patients.

This study examines the contribution of the lexical/verbal channel to emotional processing in 16 right brain-damaged (RBD), 16 left brain-damaged (LBD) and 16 normal control (NC) right-handed adults. Emotional lexical perception tasks were developed; analogous nonemotional tasks were created to control for cognitive and linguistic factors. The three subject groups were matched for gender, age and education. The brain-damaged groups were similar with respect to cerebrovascular etiology, months post-onset, sensory-motor status and lesion location. Parallel emotional and nonemotional tasks included word identification, sentence identification and word discrimination. For both word tasks, RBDs were significantly more impaired than LBDs and NCs in the emotional condition. For all three tasks, RBDs showed a significantly greater performance discrepancy between emotional and nonemotional conditions than did LBDs or NCs. Results were not affected by the valence (i.e. positive/negative) of the stimuli. These findings suggest a dominant role for the right hemisphere in the perception of lexically-based emotional stimuli.


Opposite hemispheric activations as a result of emotionally threatening and non-threatening words.

Twenty right-handed males participated in a tachistoscopic unilateral letter recognition task with three conditions. In the control condition, each trial consisted of three consonants that were flashed horizontally to the left or to the right visual field. In the threat and non-threat conditions, each lateral three-letter presentation was preceded by an emotionally threatening or non-threatening word presented in central fixation. Across conditions, subjects identified more letters correctly in the right visual field than in the left visual field. The concurrent presentation of threatening words resulted in a selective enhancement of left visual-field performances. The concurrent presentation of non-threatening words resulted in a selective right visual-field enhancement. Our conclusion is that threatening stimuli prime the right hemisphere and can alter predicted laterality patterns.


Role of the lateral and medial hypothalamus in the reproduction of alimentary and defensive instrumental reactions.

It was established in experiments on two dogs that a test electrical stimulation of the lateral hypothalamus reproduces an instrumental movement in the case of a developed alimentary instrumental CR to a tone and does not reproduce it in the case of a developed acid defensive instrumental CR. In the case of an electrical stimulation of the medial hypothalamus, the instrumental movement is essentially not reproduced, either in the alimentary or the defensive situations. The appearance of the instrumental movement with electro-stimulation of the LH in the alimentary situation is associated with activation of the backward conditioned connection from the motivational "alimentary" center of the LH to the representation of this movement in the motor cortex.


Statistical analysis of the functional connections between the neurons of the visual and motor cortex in different forms of conditioned reflex behavior.

The organization of interneuronal cortical connections was studied in experiments on cats with the development of delayed alimentary instrumental reflexes in response to light. The dynamics of the intra- and interstructural neuronal network at the level of the cortical projection (visual and motor) zones of the cat brain in three forms of behavior was revealed through a cross correlation analysis: the realization of the CR, in the intersignal period with the presence and absence of instrumental movements. The predominance of "informational" or "motivational" neuronal connections was observed depending upon the forms of the behavior.


Content of norepinephrine and serotonin in symmetrical divisions of the brain of rats in the norm during learning and with the administration of peptides.

The content of norepinephrine (NE) and serotonin (5-HT) in the right and left halves of the brain of rats was compared in the norm, during the development of defensive two-way avoidance conditioned reflexes (TWACR), and with the administration of peptides which influence learning and memory, namely desglycine-arginine vasopressin (DG-AVP), ACTH4-7 pro-gly-pro, and dalargin. These investigations demonstrated that the content of NE in the right cerebral hemisphere is significantly higher than in the cortex of the left. Significant differences were not detected with respect to the 5-HT content in symmetrical parts of the brain. The asymmetry of the NE content was eliminated under the influence of the development of the TWACR. The systemic administration of DG-AVP, ACTH4-7 pro-gly-pro, and dalargin essentially did not alter the 5-HT content, and decreased the NE content in the cortex and in the rest of the brain. In the process the NE content of the right and left hemisphere evened out. The data obtained point to the asymmetrical character of the action of the neuropeptides and to the greater resistance of the serotoninergic system of the brain to a functional load and the administration of peptides by comparison with the noradrenergic system.


Reinforcing effect of stimulation of the mesocerebral region of the brain of the edible snail.

Two regions of the brain of the edible snail were stimulated. The spontaneous movements, either opening or closing, of the opening of the mantle cavity served as the signal for the stimulation. The stimulation of the region of the mesocerebrum of the edible snail in a semi-intact preparation may serve as a positive reinforcement of intercurrent behavior, while stimulation of the rostral portion of the parietal ganglia may serve as a negative reinforcement. Depending upon whether the movement itself or its absence is reinforced, the change in the intercurrent behavior may change sign.


Reactions of neurons of the mediodorsal nucleus of the thalamus to the stimulation of peripheral nerves.

The reactions of neurons of the associative mediodorsal nucleus of the thalamus to a solitary stimulation of the radial, sciatic, and splanchnic nerves were studied in conditions of an acute experiment in anesthetized and immobilized cats. There were 91.85, 90.56, and 81.35% reactive neurons, respectively. They were mainly concentrated in the parvocellular division of the nucleus. A high degree of convergence (82.6%) of somatic and visceral signals was found and their interaction was of the reciprocal blocking type.


Development of auditory sensitivity of altricial birds: absolute thresholds of the generation of evoked potentials.

The thresholds of the generation of EP in the L field of two to nine day old pied flycatcher nestlings in response to monotonal bursts of varied frequency were investigated. The entire range of auditory sensitivity was divided into three channels on the basis of the character of the age-related dynamics of the thresholds (two to nine days of life): low-frequency (0.3-1.6 kHz), middle- (1.5-4.0 kHz), and high-frequency (5.0-8.0 kHz). Widening of the auditory range in the direction of high frequencies on the 4th to 5th days of nest life was demonstrated. It was shown that the development of auditory sensitivity continues in all three channels in the post-embryonic period (two to nine days after hatching), and that each of these is characterized by its own thresholds time course.


Changes associated with the organization of motor acts in the on-going frequency of the discharges of neurons of subcortical structures of the human brain.

The impulse activity of subcortical structures was recorded in 16 parkinsonian patients (six women) using deep electrodes implanted in the strio-pallido-thalamic system on the basis of treatment and diagnostic indications. The patients voluntarily participated in four psychological tests. Two groups of pallidal and thalamic neuronal populations (neuronal populations associated with the response and associated with the stimulus, containing 25% each out of the total number of neuronal populations recorded) were classified on the basis of evoked changes in on-going frequency in the motoric version of the odd ball test. Some of the neuronal populations associated with the response reacted primarily during counting, some during the naming of the stimulus, and some during button pressing.


Infratemporal alveolar soft part sarcoma: CT, MRI and angiographic findings.

The imaging features of a rare alveolar soft part sarcoma found in a 44-year-old female are presented. Although the tumor showed hypervascularity by angiography, CT and MRI suggested slow growth. Despite this relatively benign appearance, alveolar soft part sarcoma is one of the most malignant sarcomas.


Modules of cortical neurons and their "self-assembly".

The data we have by now accumulated on the cytoarchitectonics of the cerebral cortex, as well as published data, suggest that some of the neurons are structurally combined into compact clusters (ensembles, blocks), and that the majority of them participate in the construction of these clusters by directing the terminal branches of their axons to them. The collaterals of projection, associative, and callosal nerve cells, as well as the axons of interneurons which accomplish local interneuronal closures, can combine individual elements of the ensembles into a unified morphofunctional system. The collaterals of the axons of a block of neurons spread divergently to neurons disposed along the perimeter, while the axons of the latter converge reciprocally to the neurons of the cluster, forming a maximum (focus) of the arborization of the axonal terminals there; this makes it possible actively to isolate modules of nerve cells by accomplishing their self-assembly.


Pulsatile brain movement and associated hydrodynamics studied by magnetic resonance phase imaging. The Monro-Kellie doctrine revisited.

Brain tissue movements were studied in axial, sagittal and coronal planes in 15 healthy volunteers, using a gated spin echo MRI sequence. All movements had characteristics different from those of perfusion and diffusion. The highest velocities occurred during systole in the basal ganglia (maximum 1.0 mm/s) and brain stem (maximum 1.5 mm/s). The movements were directed caudally, medially and posteriorly in the basal ganglia, and caudally-anteriorly in the pons. Caudad and anterior motion increased towards the foramen magnum and towards the midline. The resultant movement occurred in a funnel-shaped fashion as if the brain were pulled by the spinal cord. This may be explained by venting of brain and cerebrospinal fluid (CSF) through the tentorial notch and foramen magnum. The intracranial volume is assumed to be always constant by the Monro-Kellie doctrine. The intracranial dynamics can be viewed as an interplay between the spatial requirements of four main components: arterial blood, capillary blood (brain volume), venous blood and CSF. These components could be characterized, and the expansion of the arteries and the brain differentiated, by applying the Monro-Kellie doctrine to every moment of the cardiac cycle. The arterial expansion causes a re-moulding of the brain that enables its piston-like action. The arterial expansion creates the prerequisites for the expansion of the brain by venting CSF to the spinal canal. The expansion of the brain is, in turn, responsible for compression of the ventricular system and hence for the intraventricular flow of CSF.


Conditioned avoidance reflex and intersignal movements: interrelationship of cardiac and motor components.

The correlation of the heart rate (HR), of a conditioned motoric reaction, and intersignal movements was studied during the development of a conditioned reflex (CR) of avoidance using V.P. Petropavlovskii's methods. The level of defensive motivation, assessed on the basis of the magnitude of changes in HR was maximal against the background of a firmly developed CR during the course of the latent period of the conditioned motoric reaction. A sharp decrease in the level of defensive excitation took place against the background of the latter, expressed in the prolonged holding of the extremity in place in the safety zone (height of rise 5-10 cm, guaranteeing the avoidance of electrodermal stimulation of the extremity). Intersignal movements of two types were described: the first in the form of phasic flexions; the second repeats the conditioned motoric reaction of the holding of the extremity in place. A reduction in defensive excitation took place against the background of the latter, like that which took place during the elevation of the extremity against the background of the combination.


Intraparenchymal blood-fluid levels in traumatic intracerebral haematomas.

Blood-fluid levels within the cerebral parenchyma are observed more frequently on CT and MRI in traumatic intracerebral haematomas than in those of other aetiologies. The intraparenchymal blood-fluid interface can be formed without a fluid cavity. It is suggested that the blood-fluid levels represent layering of red blood cells within areas of contusion necrosis as well as extensive contusion oedema. The more extensive the damage to brain tissue, the more often blood-fluid levels formed. A poorer outcome can be therefore predicted when an intraparenchymal blood-fluid interface is seen.


Corpus callosum lesions after closed head injury in children: MRI, clinical features and outcome.

Thirty-four children who sustained moderate to severe closed head injury underwent magnetic resonance imaging (MRI). Eight (24%) had MRI evidence of corpus callosum injury, most commonly within the posterior body and splenium. In contradistinction to reports in adults, there was no definite relationship between callosal injury and lower initial Glasgow Coma Scale scores, nor was there a significantly higher incidence of primary brain-stem lesions, diffuse axonal shear injury or intraventricular hemorrhage. In none of these 8 children did the initial admission computed tomography show evidence of callosal injury. Callosal injuries on MRI are not necessarily a poor prognostic finding, the majority of the 8 children showing good functional recovery.


MRI and SPECT findings in amyotrophic lateral sclerosis. Demonstration of upper motor neurone involvement by clinical neuroimaging.

MRI was performed in 21 patients and single photon emission computed tomography (SPECT) with N-isopropyl-p-123I iodoamphetamine in 16 patients, to visualize upper motor neurone lesions in amyotrophic lateral sclerosis. T2-weighted MRI revealed high signal along the course of the pyramidal tract in the internal capsule and cerebral peduncle in 4 of 21 patients. SPECT images were normal in 4 patients, but uptake was reduced in the cerebral cortex that includes the motor area in 11.


Serial MRI in Fukuyama type congenital muscular dystrophy.

Serial MRI of the brain of a female infant with Fukuyama type congenital muscular dystrophy (FCMD) is presented. Initial MRI revealed diffuse abnormal signal in the cerebral white matter extending peripherally. On follow-up studies, the abnormal signals disappeared or decreased from the posterior to anterior, and from central to peripheral. These changes in signal intensity correlate well with the process of myelination as demonstrated in histochemical studies. It appears that the abnormal signals in FCMD are caused by delayed myelination. When abnormal signal intensity is seen in the cerebral white matter of a developmentally delayed infant, serial MRI may be used to follow the course of the illness.


MRI demonstration of midbrain deformity in association with Chiari malformation.

The differentiation of Chiari malformation from intrinsic brainstem neoplasm in adults can be difficult. We report three patients presenting with brainstem signs, in whom midbrain abnormality was detected on computed tomography and interpreted as evidence of intrinsic tumour. Subsequent investigation by magnetic resonance imaging revealed evidence of Chiari I malformation in all three cases and a syrinx in two. The association of Chiari I with deformity of the midbrain or pons has not been described previously.


Pericallosal lipoma extending through the choroidal fissure: US/CT/MRI correlation.

Choroid plexus lipomas (CPL) are known to be associated with pericallosal lipomas (lipomas of the corpus callosum--LCC). Twenty-six cases have previously been reported. Approximately half of these lipomas are connected via the choroidal fissure (LCC-CPL); this connection is almost always bilateral. We present an unusual unilaterally connected LCC-CPL in a neonate.


Supracerebellar arachnoid cyst and reversible tonsillar herniation: magnetic resonance imaging and pathophysiological considerations.

A large supracerebellar arachnoid cyst was associated with herniation of the cerebellar tonsils and deformity of the cervicomedullary junction in an adult. Magnetic resonance imaging showed partial restoration of normal anatomy following surgery and clinical improvement, which helped in the formulation of a etiopathogenetic hypotheses.


Magnetic resonance imaging and angiography in hemifacial spasm.

We used magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) to investigate 14 patients with unilateral hemifacial spasm (HS) and 20 controls. The relationship of the seventh and eighth cranial nerves to adjacent vessels was best visualized on the contiguous flow sensitive 3D-FISP images. Reconstruction of projectional MRA was helpful to assess the complex architecture of the vertebrobasilar system. Neurovascular contact in the facial nerve root exit zone was present in 4 of 20 controls and in 12 of 14 patients, in whom it predicted the affected side. These results support previous findings of surgical and electrophysiological investigations that local irritation of the facial nerve is the most possible explanation for HS. MRI and MRA provide vascular and brain tissue diagnosis in a single non-invasive examination and should be recommended as primary neuroradiological procedure in HS.


Accessory nerve neuroma presenting as recurrent jugular foramen syndrome.

We report a patient with spontaneous recovery and recurrence of a jugular foramen syndrome secondary to an accessory nerve neuroma. He showed sudden onset of unilateral palsy of the ninth, tenth and eleventh cranial nerves in 1982. He recovered almost fully and in 1990 the palsies recurred. MRI revealed a small mass in the right jugular foramen. The tumour was resected via suboccipital craniectomy, and diagnosed as a neuroma of the eleventh cranial nerve.


Haemangioma of the petrous bone: MRI.

Gd-DTPA-enhanced MRI provided accurate demonstration of the site and extension of a haemangioma of the petrous bone. Enhanced-MRI could allow early detection and differentiation from the other more common tumours of the geniculate ganglion area, thereby permitting the surgeon to remove the tumour, while preserving the facial nerve. CT is, however, required to display the characteristic ossification in these tumours.


Follow-up MRI in dural arteriovenous malformations involving the cavernous sinus: emphasis on detection of venous thrombosis.

Six patients with a dural arteriovenous malformation (dural AVM) involving the cavernous sinus were followed up with magnetic resonance imaging in order to assess change in the lesions. Spin-echo (SE) imaging of three patients in whom the AVM appeared to have closed at least 1 month earlier (two of them spontaneously, and one after external carotid artery embolization) showed neither apparent flow void in the involved cavernous sinus nor evidence of venous thrombosis. SE images of the other three patients who had not been cured by external carotid artery embolization (two of whom were examined within a week of treatment), detected persisting arteriovenous shunts, including high-flow cortical venous drainage, seen as flow void. Two-dimensional time-of-flight MR angiography (2D TOF MRA) was performed simultaneously in three patients. Whereas shunting blood and the normal cavernous sinus were of high intensity, presumed thrombosed cavernous sinuses were isointense with stationary brain tissue. SE imaging can confirm the resolution of arteriovenous shunts, but poorly delineates very acute and chronic thrombosis of the draining veins. In contrast, 2D TOF MRA directly demonstrates flowing blood, permitting the diagnosis of venous thrombosis; it should be included in follow-up of a dural AVM involving the cavernous sinus when venous thrombosis is suspected.


A scalp lesion over an extracerebral mass: a sign of a radiation-induced meningioma.

Radiation-induced meningiomas have a characteristic biological behaviour, so that their recognition is important as regards follow-up. We stress the importance of a scalp lesion over the meningioma on magnetic resonance imaging as a sign of previous radiotherapy.


CT and MRI in hydatid disease of cervical vertebrae.

Hydatid disease (HD) of the cervical spine is rare. A case investigated by computed tomography (CT) and magnetic resonance imaging (MRI) is presented. While CT shows the bone lesion better, MRI is superior in demonstrating compression of neural structures. The complementary use of CT and MRI in such cases is suggested.


Myelopathy due to large veins draining recurrent spontaneous caroticocavernous fistula.

A 45-year-old woman developed a myelopathy 9 years after a spontaneous left caroticocavernous fistula (CCF) was treated by a trapping procedure, with clipping distal to the fistula and ligation of the common carotid artery. Spinal MRI and vertebral angiography revealed recurrence of the CCF and gigantic tortuous veins draining through the brain stem down to the midcervical spinal cord. The abnormal veins and myelopathy disappeared after surgical closure of the CCF.


Intraoperative sonography of intramedullary spinal cord tumours.

Intraoperative spinal sonography was performed 23 times in 20 patients with intramedullary spinal cord tumours, and the sonographic features were examined. Eight cases of astrocytoma were classified into three types: type 1, seen in 3 children, had intramedullary, circular or oval, hyperechogenic multiple tumour shadows; type 2 presented inter-multimyelomere, relatively well-defined single tumour shadows corresponding to grade III and I for two juvenile and aged cases each, respectively; and type 3 appeared ill-defined and diffusely infiltrating. The relationships between these types, the ages of patients and histological grades were considered a potential clue to mechanisms of occurrence and infiltration of astrocytoma. All 7 ependymomas had syrinxes, of three types; central canal was very large, the tumour lying within it like an island; or the tumour was in contact with a cephalocaudal side part of the syrinx; or the tumour had a syrinx or cyst. Sonographic images thus differ according to the tumour, but differential diagnosis is currently limited. Development of sonographic equipment, with upgrading its resolving power are hoped for.


Intraoperative ultrasonography of extramedullary spinal tumours.

Intraoperative spinal sonography (IOSS) was performed in 28 patients with extramedullary spinal tumours. Images were obtained of 31 tumours, because 2 patients had multiple tumours. There were 17 neurilemmomas, 9 meningiomas and 2 dermoid cysts. All tumours appeared well-defined and highly echogenic. There was no difficulty differentiating extramedullary spinal tumours from intramedullary masses excepting case, a big neurilemmoma at the conus medullaris. All images were assessed with reference to the surface of the lesions, the existence of cysts, and movement. Neurilemmomas had smooth surfaces, some cysts, and exhibited a "floating" movement. Meningiomas had irregular surfaces, were more highly echogenic than neurilemmomas, and adhered tightly to the dura mater. However, some neurilemmomas and meningiomas did not have these, and it was not always possible to differentiate them. Although IOSS has limitations of resolution, it gave useful information about the size of the tumours, the degree of displacement of the spinal cord, and even about the type of tumour in some cases. It was extremely helpful to the surgeon.


Myelographic and MRI appearances of a thoracic spinal extradural arachnoid cyst of the spine with extra- and intraspinal extension.

An unusual arachnoid cyst of the thoracic spine is reported. The clinical and neuroradiological features are described.