Behavioral Neurology



Behavioral Neurology





I. Aphasia



  • Broca aphasia



    • Description: disordered grammar, nonfluent, linguistic dysprosody, poor naming, poor repetition, paraphasias


    • Lesion: frontal operculum lower motor cortex, anterior division of left middle cerebral artery


  • Chronic Broca aphasia



    • Description: mutism or hyperkinetic, spastic


    • Lesion: dorsolateral frontal, opercular subcortical extension


  • Wernicke aphasia



    • Description: paraphasic or empty content, neologisms, circumlocutions, paragrammatism, poor naming, apraxia, poor repetition


    • Lesion: superior temporal gyrus


  • Conduction aphasia



    • Description: poor repetition, hesitation, variable naming, decreased auditory, short-term memory


    • Lesion: supramarginal gyrus (arcuate fibers)


  • Transcortical motor aphasia



    • Description: imitation block, echolalia, normal repetition, poor syntax, improves with direct dopamine agonists


    • Lesion: large dorsolateral frontal lesions that spare the perisylvian cortex


  • Transcortical sensory aphasia



    • Description: fluent semantic paraphasias circumlocutions, jargon, normal repetition, poor comprehension, poor naming, poor reading


    • Lesion: middle or inferior temporal gyrus that spares the perisylvian cortex


  • Aphemia



    • Description: mutism or very effortful speech, but writing is preserved


    • Lesion: anterior or medial frontal or white matter undercutting Broca area, but sparing the perisylvian cortex


II. Dyslexia



  • Alexia without agraphia



    • Description: inability to read with preserved ability to write


    • Lesion: left occipital lobe with splenium of corpus callosum



  • Neglect dyslexia



    • Description: failure to identify initial letters in a letter string; neglect syndrome component


    • Lesion: right neglect dyslexia sometimes seen with left brain damage


  • Attentional dyslexia



    • Description: preserved single words, disrupted composition, sometimes preserved singleletter reading with compromised letter string reading


    • Lesion: Alzheimer disease, attention disorder


  • Deep dyslexia



    • Description: semantic errors, concrete words easier, difficulty with functors (articles and pronouns), unable to read nonwords such as “PRAT”


    • Lesion: large perisylvian lesions, usually associated with aphasias


  • Phonologic dyslexia



    • Description: reading without print to sound conversion, impaired reading of nonword letter strings


    • Lesion: dominant perisylvian cortex, superior temporal lobe, angular gyrus


  • Surface dyslexia



    • Description: inability to pronounce words of nonphonologic pronunciation (i.e., irregular words such as cough, rough, bough)


    • Lesion: Alzheimer disease, poorly localized


III. Agraphia



  • Apraxic agraphia



    • Description: difficulty writing letters (motor control)


    • Lesion: superior parietal lobe dominant


  • Spatial agraphia



    • Description: spatial orientation abnormal, sometimes associated with neglect


    • Lesion: nondominant parietal lobe


  • Parkinsonian agraphia



    • Description: micrographia, slow, may have motor perseveration


    • Lesion: poorly localized


  • Callosal agraphia



    • Genu: apraxic agraphia with inability to type


    • Body: apraxic agraphia with ability to type


    • Splenium: unilateral aphasic agraphia (incorrect spellings)


  • Dementia agraphia



    • Description: semantic errors, homophone errors (night for knight), spatial agraphia


    • Lesion: Alzheimer disease


  • Isolated agraphia



    • Description: spelling errors


    • Lesion: possibly second frontal gyrus (Exner area)


  • Acalculia



    • Description: abnormalities of number processing


    • Lesion: left posterior hemisphere


IV. Apraxia



  • Limb kinetic apraxia



    • Description: loss of finely graded finger movements (subtle form of weakness)


    • Lesion: contralateral parietal lobe



  • Ideomotor apraxia



    • Description: movement production errors (positional or spatial errors)


    • Lesion: dominant inferior parietal lobe, ± corpus callosum, ± SMA supplementary motor area


  • Disassociation apraxia



    • Description: no recognizable action or command, but use objects well


    • Lesion: callosal disconnections


  • Conduction apraxia



    • Description: more impaired with imitating than when positioning


    • Lesion: unknown


  • Ideational apraxia



    • Description: movement sequence errors, required to complete a task


    • Lesion: dementia


  • Conceptual apraxia (sometimes referred to as ideational apraxia)



    • Description: decreased tool—object action knowledge


    • Lesion: dementia, left parietal


V. Visual Agnosia

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Sep 8, 2016 | Posted by in NEUROLOGY | Comments Off on Behavioral Neurology

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