Effect of Dual-Tasking on Postural Control in Subjects With Nonspecific Low Back Pain Effects of piroxicam-beta-cyclodextrin sachets on abnormal postural sway in patients with chronic low back pain. Effectiveness of fingertip light contact in reducing postural sway in older people. Postural sway in low back pain: Effects of dual tasks. Physical Activity and Postural Control in the Elderly: Coupling between Visual Information and Body Sway The relative timing of trunk muscle activation is retained in response to unanticipated postural-perturbations during acute low back pain Experimental muscle pain changes feedforward postural responses of the trunk muscles Altered postural control in anticipation of postural instability in persons with recurrent low back pain. Effects of Pelvic Asymmetry and Low Back Pain on Trunk Kinematics During Sitting: A Comparison With Standing Sensorimotor integration in human postural control. Impaired postural compensation for respiration in people with recurrent low back pain Control of sway using vibrotactile feedback of body tilt in patients with moderate and severe postural control deficits.
Study Design . Three factors mixed- design with 1 between-subject and 2 within-subject factors . Objective . To compare the main effects and interactions of postural and cognitive difficulty on quiet stance between subjects with and without nonspecific low back pain ( LBP ) . Summary of Background Data . The interference between postural control and cognitive tasks depends on factors such as sensorimotor/cognitive integrity . Changes in peripheral sensory and muscular systems as well as cognitive processes have been observed in LBP patients . It was hypothesized that the effect of cognitive task on postural performance might be different in subjects with nonspecific LBP as compared with healthy individuals . To the authors ’ knowledge this has not been investigated before . Methods . Postural stability was measured by center of pressure parameters while nonspecific LBP ( n = 22 ) and healthy ( n = 22 ) subjects r and omly performed quiet st and ing task with 3 levels of difficulty ( rigid-surface eyes open , rigid-surface eyes-closed , and foam-surface eyes-closed ) in isolation or concurrently with an easy or difficult digits backward cognitive task . Results . Subjects with nonspecific LBP had less postural sway than healthy subjects , while postural sway decreased with increase in the level of cognitive difficulty . Nonspecific LBP and healthy subjects had larger postural sway at more difficult sensory conditions such as rigid-surface eyes-closed and foam-surface eyes-closed . The response to dual-tasking was not significantly different between the 2 groups . Conclusion . The dual-tasking did not change the postural performance of nonspecific LBP subjects with low level of pain and disability differently compared to healthy subjects BACKGROUND The clinical effects of piroxicam-beta-cyclodextrin ( PBC ) in sachet form have been surveyed in patients with osteoarthritic or acute pain in western countries , but scarcely studied in those with chronic low back pain ( LBP ) , and never investigated in the field of postural sway . The aim of this study was to evaluate the clinical effects of PBC in sachet form prescribed in patients with chronic backache in local Asian when compared with those of plain piroxicam . METHODS After r and omized allocation and experimental exclusion , a total of 42 eligible patients were r and omized into two groups , the sachet group ( n = 23 ) and the piroxicam tablet group ( n = 19 ) . Both groups were administered the same dosage , orally per day ( daily dose = 20 mg ) . The duration of trial was 28 days . Efficacy was assessed with pain score , disability index and postural sway . RESULTS The patients in sachet group showed greater improvement in pain score and disability index than those who took piroxicam tablets . There were significantly lower sway velocity and intensity at almost all different conditions than baseline profiles in both groups ( P < 0.05 ) . However , there was no significant difference of sway velocity and intensity in the piroxicam tablets group with regard to eyes open or eyes closed in 20 degrees dorsiflexion . CONCLUSIONS Piroxicam-beta-cyclodextrin ( PBC ) sachet may have greater improvement in the treatment of chronic LBP and possess the extended effects on postural abnormality relevant to chronic LBP BACKGROUND AND OBJECTIVE haptic cues from fingertip light touch ( LT ) with a stationary surface reduce postural sway even at non-mechanically supportive force levels . Aim of this study was to determine the effects of LT on postural sway in older compared with younger persons . SUBJECTS twenty young ( age 20 - 29 , mean 23.9 + 2.5 ) and 20 older participants ( age 65 - 83 , mean 74.3 + 6.4 ) . METHODS subjects stood in the semi-t and em position on a firm surface , and their postural sway was quantified using a force platform . Experimental trials , r and omised across subjects , included two sight conditions ( vision and no vision ) and three contact conditions ( no touch , NT ; light touch , LT ; and force touch , FT ) . The measured parameters were the length and the area of centre of pressure sway ( COP-L and COP-A ) and the mean velocity of COP displacements in the anterior-posterior ( COP-AP ) and medial-lateral ( COP-ML ) direction . RESULTS for all variables , the analysis showed significant differences between contact conditions , sight conditions and age . Contact-age interaction was significant between NT and LT conditions , with older participants showing greater decrease in postural sway than younger participants , but not between FT and LT conditions . CONCLUSIONS results indicate that the effectiveness of LT in reducing postural sway may be greater in older than in younger persons , perhaps because in older persons haptic cues from upper extremity might counterbalance sub- clinical sensory loss in the lower extremities . This finding supports the hypothesis that older people may sometimes use a walking aid as an informative device and suggests that during balance training external aids should not be used Recurrence quantification analysis ( RQA ) , a nonlinear method of postural analysis , was used to explore the effects of dual-tasking on postural performance in people with nonspecific low back pain ( LBP ) compared with healthy participants .  Postural performance was quantified by RQA % recurrence , % determinism , entropy and trend .  People with nonspecific LBP ( n=22 ) and unimpaired individuals ( n=22 ) r and omly performed quiet st and ing tasks with three levels of difficulty ( rigid-surface eyes open , rigid-surface eyes closed and foam-surface eyes closed ) . These tasks were performed in isolation or concurrently with an easy or difficult cognitive task . Increasing postural difficulty was associated with higher % determinism , higher entropy and lower trend in anteroposterior ( AP ) and mediolateral ( ML ) directions in people with LBP and healthy participants .  All RQA variables in the ML direction decreased as cognitive conditions became more difficult . Significant interactions between group and cognitive difficulty were shown for % recurrence , % determinism and trend in the AP direction . While healthy participants decreased % recurrence and trend by increasing the level of cognitive difficulty , the LBP patients did not . This preliminary study suggests that LBP may be one factor that modulates the posture-cognition interaction Background : Aging is characterized by a decline in the postural control performance , which is based on a coherent and stable coupling between sensory information and motor action . Therefore , changes in postural control in elderlies can be related to changes in this coupling . In addition , it has been observed that physical activity seems to improve postural control performance in elderlies . These improvements can be due to changes in the coupling between sensory information and motor action related to postural control . Objective : The purpose of this study was to verify the coupling between visual information and body sway in active and sedentary elderlies . Methods : Sixteen sedentary elderlies ( SE ) , 16 active elderlies ( AE ) and 16 young adults ( YA ) were asked to st and upright inside a moving room in two experimental conditions : ( 1 ) discrete movement and ( 2 ) continuous movement of the room . Results : In the continuous condition , the results showed that the coupling between the movement of the room and body sway was stronger and more stable for SE and AE compared to YA . In the discrete condition , SE showed larger body displacement compared to AE and YA . Conclusions : SE have more difficulty to discriminate and to integrate sensory information than AE and YA indicating that physical activity may improve sensory integration The purpose of this study was to assess the activation of the erector spinae ( ES ) and external oblique ( EO ) in response to unanticipated , bi-directional postural perturbations before and after the induction of acute low back pain ( LBP ) in healthy individuals . An experimental session consisted of a baseline , control , and an acute LBP condition . For the control and acute LBP condition , isotonic or hypertonic saline ( HS ) , respectively , was injected into the right ES muscle . In each condition , participants stood on a moveable platform during which 32 r and omized postural perturbations ( 8 repetitions of 4 perturbation types : 8 cm anterior slides , 8 cm posterior slides , 10 ° anterior tilts , and 10 ° posterior tilts ) with varying inter-perturbation time intervals were performed over a period of 4–5 min . Bilateral surface electromyography ( EMG ) was recorded from the ES and EO in addition to subjective pain records . During the acute LBP condition : ( 1 ) the onset time of the ES and EO was delayed for the forward and backward sliding perturbations ( P < 0.05 ) ; ( 2 ) EMG amplitude was reduced bilaterally for all perturbations ( P < 0.05 ) ; ( 3 ) the order of activation and interval between the onset times of the ES and EO were unaltered and ( 4 ) ES , but not EO , activity was adjusted to account for the directional differences between the perturbations . This study revealed that re-establishment of posture and balance was a result of the individuals ’ ability to rapidly modulate ES with respect to EO activity and that the bi-directional postural responses , although shifted in time and amplitude , retained temporal features in the presence of acute LBP Many studies have identified changes in trunk muscle recruitment in clinical low back pain ( LBP ) . However , due to the heterogeneity of the LBP population these changes have been variable and it has been impossible to identify a cause-effect relationship . Several studies have identified a consistent change in the feedforward postural response of transversus abdominis ( TrA ) , the deepest abdominal muscle , in association with arm movements in chronic LBP . This study aim ed to determine whether the feedforward recruitment of the trunk muscles in a postural task could be altered by acute experimentally induced LBP .  Electromyographic ( EMG ) recordings of the abdominal and paraspinal muscles were made during arm movements in a control trial , following the injection of isotonic ( non-painful ) and hypertonic ( painful ) saline into the longissimus muscle at L4 , and during a 1-h follow-up . Movements included rapid arm flexion in response to a light and repetitive arm flexion-extension . Temporal and spatial EMG parameters were measured . The onset and amplitude of EMG of most muscles was changed in a variable manner during the period of experimentally induced pain . However , across movement trials and subjects the activation of TrA was consistently reduced in amplitude or delayed . Analyses in the time and frequency domain were used to confirm these findings . The results suggest that acute experimentally induced pain may affect feedforward postural activity of the trunk muscles . Although the response was variable , pain produced differential changes in the motor control of the trunk muscles , with consistent impairment of TrA activity Insight into the mechanisms of altered postural control in persons with low back pain ( LBP ) could lead to better interventions for patients with LBP . This study investigated ( 1 ) whether persons with recurrent LBP have an altered body inclination , and ( 2 ) whether anticipation of postural instability further alters body inclination . Thirty-three young healthy individuals and 56 young persons with recurrent LBP participated in this study .  The upright st and ing posture was evaluated by means of two piezo-resistive electrogoniometers and a force platform for the conditions as follows : ( 1 ) quiet stance with and without vision , and ( 2 ) in anticipation of postural instability due to a ballistic arm movement or ankle muscle vibration . No differences in body inclination were observed when visual information was available between the two groups ( P>0.05 ) . However , significant more forward inclination was seen in the persons with recurrent LBP when vision was occluded ( + 7.4 % ) and in anticipation of postural instability ( + 19 % ) ( P<0.05 ) compared to the healthy individuals . The results suggest that young persons with recurrent LBP have an altered body inclination that might be caused by anticipation of postural instability . The adopted forward inclined posture may potentially be a factor in the recurrence of LBP Study Design . A prospect i ve study was conducted on a group of patients with unilateral nonspecific low back pain ( LBP ) and healthy controls . Objectives . To answer 3 questions : ( 1 ) Does pelvic asymmetry measured in st and ing affect the dynamics of motion performed in sitting ? ( 2 ) Do patients with LBP perform trunk motions differently from non-LBP participants in sitting position ? and ( 3 ) Do the kinematics of lateral flexion and axial rotation differ between sitting and st and ing positions ? Summary of Background Data . The effect of pelvic asymmetry on trunk motion while sitting remains unclear . LBP has been associated with altered trunk kinematics in st and ing ; however , there is limited information available describing trunk kinematics in sitting position in comparison to st and ing . Methods . Pelvic asymmetry was measured in 54 patients with unilateral nonspecific LBP and 59 control subjects .  A motion- analysis system was used to test the  range and symmetry of lateral flexion and axial rotation  in sitting and st and ing positions . Bivariate correlations , regression , multivariate analysis of variance , and paired sample t tests were used to test for associations between variables and differences between groups . Results . We found significant : ( 1 ) correlations between pelvic asymmetry and asymmetric trunk motion performed in sitting , ( 2 ) differences between the LBP and control groups in patterns of trunk motion performed in a sitting posture , and ( 3 ) differences between kinematics of motions performed in sitting versus st and ing postures . Conclusions . This study shows a link between pelvic asymmetry and altered trunk motion in sitting position . We suggest that people with LBP may have a distinct compensatory mechanism , secondary to pelvic asymmetry , which puts the lumbar spine under higher stress . Movement asymmetry , rather than range of motion , may be a better indicator of disturbed function for people with LBP . Structural and functional asymmetries are factors that may be considered in the seating design and work environment It is generally accepted that human bipedal upright stance is achieved by feedback mechanisms that generate an appropriate corrective torque based on body-sway motion detected primarily by visual , vestibular , and proprioceptive sensory systems . Because orientation information from the various senses is not always available ( eyes closed ) or accurate ( compliant support surface ) , the postural control system must somehow adjust to maintain stance in a wide variety of environmental conditions . This is the sensorimotor integration problem that we investigated by evoking anterior-posterior ( AP ) body sway using pseudor and om rotation of the visual surround and /or support surface ( amplitudes 0.5 - 8 degrees ) in both normal subjects and subjects with severe bilateral vestibular loss ( VL ) .  AP rotation of body center-of-mass ( COM )  was measured in response to six conditions offering different combinations of available sensory information .  Stimulus-response data were analyzed using spectral analysis to compute transfer functions and coherence functions over a frequency range from 0.017 to 2.23 Hz . Stimulus-response data were quite linear for any given condition and amplitude . However , overall behavior in normal subjects was nonlinear because gain decreased and phase functions sometimes changed with increasing stimulus amplitude . " Sensory channel reweighting " could account for this nonlinear behavior with subjects showing increasing reliance on vestibular cues as stimulus amplitudes increased . VL subjects could not perform this reweighting , and their stimulus-response behavior remained quite linear . Transfer function curve fits based on a simple feedback control model provided estimates of postural stiffness , damping , and feedback time delay . There were only small changes in these parameters with increasing visual stimulus amplitude . However , stiffness increased as much as 60 % with increasing support surface amplitude . To maintain postural stability and avoid resonant behavior , an increase in stiffness should be accompanied by a corresponding increase in damping . Increased damping was achieved primarily by decreasing the apparent time delay of feedback control rather than by changing the damping coefficient ( i.e. , corrective torque related to body-sway velocity ) . In normal subjects , stiffness and damping were highly correlated with body mass and moment of inertia , with stiffness always about 1/3 larger than necessary to resist the destabilizing torque due to gravity . The stiffness parameter in some VL subjects was larger compared with normal subjects , suggesting that they may use increased stiffness to help compensate for their loss . Overall results show that the simple act of st and ing quietly depends on a remarkably complex sensorimotor control system This study evaluated the degree to which the disturbance to posture from respiration is compensated for in healthy normals and whether this is different in people with recurrent low back pain ( LBP ) , and to compare the changes when respiratory dem and is increased . Angular displacement of the lumbar spine and hips , and motion of the centre of pressure ( COP ) , were recorded with high resolution and respiratory phase was recorded from ribcage motion . With subjects st and ing in a relaxed posture , recordings were made during quiet breathing , while breathing with increased dead-space to induce hypercapnoea , and while subjects voluntarily increased their respiration to match ribcage expansion that was induced in the hypercapnoea condition . The relationship between respiration and the movement parameters was measured from the coherence between breathing and COP and angular motion at the frequency of respiration , and from averages triggered from the respiratory data . Small angular changes in the lumbopelvic and hip angles were evident at the frequency of respiration in both groups . However , in quiet st and ing , the LBP subjects had a greater displacement of their COP that was associated with respiration than the control subjects . The LBP group had a trend for less hip motion . There were no changes in the movement parameters when respiratory dem and increased involuntarily via hypercapnoea , but when respiration increased voluntarily , the amplitude of motion and the displacement of the COP increased in both groups . The present data suggest that the postural compensation to respiration counteracts at least part of the disturbance to posture caused by respiration and that this compensation may be less effective in people with LBP We evaluated the effect of the vibrotactile display of body tilt upon the postural stability of vestibulopathic subjects during st and ing . Two groups were studied : those with moderate and with severe deficits as defined by postural stability test scores . They were studied under conditions of distorted sensory input , and during anterior-posterior perturbations .  Seventeen subjects , with uni- or bilateral vestibular deficits , as determined by electronystagmography and vertical axis rotation , were tested using  Equitest computerized dynamic posturography ( CDP ) . Based on their performance on the CDP they were divided into two groups having either moderate ( nine subjects ) or severe ( eight subjects ) postural control deficits . Their anterior-posterior ( A/P ) body motion at the waist was measured with a micromechanical rate gyroscope and a linear accelerometer . The result ing tilt estimate was displayed by a vibrotactile array attached to the torso . The vibration served as a tilt feedback to the subject . The subject 's performance was evaluated using the root-mean-square ( RMS ) of both the A/P body motion and center-of-pressure ( CoP ) estimates . Sensory distortions were introduced using the Equitest Sensory Organization Tests ( SOT ) . These tests are design ed to distort A/P sensory inputs while st and ing . The SOT 5 distorts proprioceptive information about ankle joint movement , while the subject st and s eyes-closed on a moving support platform that measures foot pressure . The SOT 6 adds distorted visual information about body movement instead of testing with eyes closed . Perturbations were introduced using the Equitest Motor Control Tests ( MCT ) . These move the support platform forward or backward with small , medium and large displacements in the horizontal plane while measuring subjects ' foot pressure responses . We used the medium and large backward tests . Vibrotactile display of body tilt reduced the subjects ' A/P sway and improved their balance . The finding was more evident for those subjects with severe deficits than those moderate ones . This trend was found for both SOT 5 and 6 , as well as the medium and large MCT . Additionally , during the MCT , the peak deflection and mean recovery time also decreased significantly
A previous review concluded that postural sway is increased in patients with low back pain ( LBP ) .
In a minority of studies , a decreased sway was found in LBP patients .
There were no systematic differences between studies finding an effect and those reporting no effect of LBP .
The proportion of studies finding between-group differences did not increase with increased complexity of sensory manipulations .
However , more detailed analysis of the literature shows that postural deficit may be dependent on experimental conditions in which patients with LBP have been assessed .
The research question to be answered in this review was : " Is there any difference in postural sway between subjects with and without LBP across several sensory manipulation conditions ? " .