the acquired alexias may be categorized into posterior , anterior , central and deep alexias .
analagous to semantic paraphasias , semantic paralexias constitute the substitution of content related words during reading . unlike the analogous subcortical aphasias such as thalamic aphasia , subcortical syndromes of alexia have rarely been described .
this report depicts a patient with thalamic alexia with features of deep alexia ( or paralexia ) , the latter which has not been described after review of the english based literature .
a 57 year old white , right handed , english speaking woman with 13 years of education , presented to our stroke center with mild right sided numbness and weakness ( graded + 4/5 medical research council grading scale ) with the family reporting transient confused conversation and speech difficulty .
the clinical evaluation at our center encompasses a cognitive screening evaluation in all patients followed by psychometric assessment in selected patients described in detail elsewhere .
no dysnomia was documented . specifically visual acuity and visual fields were normal and there was no object agnosia , dyschromatopsia , dyscalculia , finger agnosia , right left disorientation , or hemineglect syndrome .
the substitution of semantically related words was documented with only mild slowing in her reading ( family corroboration ) .
cerebrovascular risk factors included a significant smoking history and on investigation hyperhomocyteinemia ( 15.6 mmol / l ) . within 4 days , the reading difficulty had normalized but she remained with mild speech dysfluency , right hand ideomotor apraxia and developed a dejerine roussey or post stroke thalamic pain syndrome .
multimodality magnetic resonance imaging investigations revealed a left lateral posterior thalamic infarct , well circumscribed on t2 weighted and diffusion weighted imaging without other brain parenchymal lesion ( figure 1 ) .
magnetic resonance angiography revealed a left internal carotid artery stenosis graded 5074% and basilar artery fenestration . 

figure 1left thalamic infarct depicted on diffusion weighted and t2 weighted magnetic resonance scan ( arrows ) . 
  left thalamic infarct depicted on diffusion weighted and t2 weighted magnetic resonance scan ( arrows ) . in view of the isolated reading impairment ,
additional psychometric examination was performed on day 3 after the stroke onset , with the boston diagnostic aphasia examination ( third edition - short form ) .
in addition , the test for semantic paralexia prone words were tested with the standard version of the boston diagnostic aphasia examination ( version iii ) ( table 1 ) . in comparison to normative data ,
notable deficiencies were noted only in speech fluency , articulation , oral word and sentence reading , picture word matching and writing . 

table 1boston diagnostic aphasia test - version iii.subtests%fluency  phrase length30  melodic line60  grammatical form70conversation expository speech100auditory comprehension  basic word discrimination100 
commands100  complex ideational material100articulation ( agility)70recitation ( automatized sequences)100repetition  words60  sentences100naming  responsive naming100  boston naming test100  special categories100paraphasia100reading  matching case and scripts100  number matching100  picture word matching40  oral word reading40  oral sentence reading80  oral sentence comprehension100  sentence / paragraph100  comprehension100wiriting  form20  letter choice40  motor facility40 

a 57 year old white , right handed , english speaking woman with 13 years of education , presented to our stroke center with mild right sided numbness and weakness ( graded + 4/5 medical research council grading scale ) with the family reporting transient confused conversation and speech difficulty .
the clinical evaluation at our center encompasses a cognitive screening evaluation in all patients followed by psychometric assessment in selected patients described in detail elsewhere .
no dysnomia was documented . specifically visual acuity and visual fields were normal and there was no object agnosia , dyschromatopsia , dyscalculia , finger agnosia , right left disorientation , or hemineglect syndrome .
the substitution of semantically related words was documented with only mild slowing in her reading ( family corroboration ) .
cerebrovascular risk factors included a significant smoking history and on investigation hyperhomocyteinemia ( 15.6 mmol / l ) .
within 4 days , the reading difficulty had normalized but she remained with mild speech dysfluency , right hand ideomotor apraxia and developed a dejerine roussey or post stroke thalamic pain syndrome .
multimodality magnetic resonance imaging investigations revealed a left lateral posterior thalamic infarct , well circumscribed on t2 weighted and diffusion weighted imaging without other brain parenchymal lesion ( figure 1 ) .
magnetic resonance angiography revealed a left internal carotid artery stenosis graded 5074% and basilar artery fenestration . 

figure 1left thalamic infarct depicted on diffusion weighted and t2 weighted magnetic resonance scan ( arrows ) . 
  left thalamic infarct depicted on diffusion weighted and t2 weighted magnetic resonance scan ( arrows ) .
in view of the isolated reading impairment , additional psychometric examination was performed on day 3 after the stroke onset , with the boston diagnostic aphasia examination ( third edition - short form ) .
in addition , the test for semantic paralexia prone words were tested with the standard version of the boston diagnostic aphasia examination ( version iii ) ( table 1 ) . in comparison to normative data ,
notable deficiencies were noted only in speech fluency , articulation , oral word and sentence reading , picture word matching and writing . 

table 1boston diagnostic aphasia test - version iii.subtests%fluency  phrase length30  melodic line60  grammatical form70conversation expository speech100auditory comprehension  basic word discrimination100 
commands100  complex ideational material100articulation ( agility)70recitation ( automatized sequences)100repetition  words60  sentences100naming  responsive naming100  boston naming test100  special categories100paraphasia100reading  matching case and scripts100  number matching100  picture word matching40  oral word reading40  oral sentence reading80  oral sentence comprehension100  sentence / paragraph100  comprehension100wiriting  form20  letter choice40  motor facility40 

the commonly referred to syndromic classification of benson and geschwind of posterior alexia ( alexia without agraphia ) , central alexia ( alexia with agraphia ) , anterior alexia ( alexia in association with expressive dysphasia ) and deep dyslexia ( primarily semantic paralexia disorder ) aptly describes most acquired reading deficiencies .
alexia secondary to isolated thalamic lesion has not been reported other than in combination with left occipital lesions , the latter lesions the usual focus .
semantic paralexia due to thalamic lesions has not been reported previously with neuroanatomical lesions mostly referred to as large perisylvian and even right hemisphere lesions implicated .
similar to subcortical aphasias , the subcortical ( thalamic ) alexia reported here is characterized by atypical alexia syndrome components .
these include relatively mild deficit , transience , a mixture of syndromic components with rapid recovery . the lack of hemispheric lesions on magnetic resonance imaging using standard t2 weighted images diffusion weighted imaging for infarct exclusion , fluid attenuation inversion recovery sequences for covert white matter lesions and gradient echo sequences to exclude minor hemorrhagic lesions , implicated the thalamic lesion alone as the critical lesion in the syndrome described .
although not a routine stroke investigative tool , functional magnetic imaging ( f - mri ) would have been an important additional neuroimaging modality to assess whether the right hemisphere had or had not played a role
. however , the rapidity of recovery precluded functional magnetic imaging , that may have helped ascertain whether right hemisphere linguistic processing was operative , the contemporary hypothesis of semantic paralexia .
 alexia may be divided into different subtypes , with semantic paralexia being particularly rare . a 57 year old woman with a discreet left thalamic 
 stroke and semantic paralexia is described . 
 language evalution with the boston diagnostic aphasia battery confirmed the semantic paralexia ( deep alexia ) . 
 multimodality magnetic resonance imaging brain scanning excluded other cerebral lesions . a good recovery ensued . 
Introduction
Case Report
Index patient
Neuroimaging
Cognitive testing
Discussion