Cortical Syndromes Flashcards
Which hemisphere is dominant for language?
Left hemisphere
- in >95% of righties
- in 60-75% of lefties
Location of Wernicke’s area
posterior 2/3 of the superior temporal gyrus of the dominant hemisphere
Function of Wernicke’s area
identification of sounds and comprehension of meaningful words
Location of Broca’s area
in the opercular and triangular portions of the inferior frontal gyrus of the dominant hemisphere
Function of Broca’s area
articulation of sounds that constitute speech
What is the arcuate fasciculus?
Subcortical white matter pathway that connects Wernicke’s and Broca’s area to allow to hear and repeat a word
Aphasia
= language defect due to dysfunction in the dominant cerebral hemisphere
Most common cause of Broca’s aphasia
frontal lobe lesions
-infarct of left MCA (middle cerebral artery) superior division
Broca’s aphasia
Expressive aphasia
- decreased fluency of spontaneous speech
- aware of deficit
Most concomitant finding associated w/ Broca’s aphasia
Right hemiparesis (weakness of right face/arm)
Most common cause of Wernicke’s aphasia
Temporal lobe lesion
-infarct of left MCA (middle cerebral artery) inferior division
Wernicke’s aphasia
Receptive aphasia
- impaired comprehension
- no meaningful content of speech- just jargon
- pts are not aware of the deficit
Most concomitant finding associated w/ Wernicke’s aphasia
Contralateral visual field cut
What is alexia w/o agraphia
Can write normally, but can’t read
=disconnection syndrome- caused by disconnection of the right and left hemispheres due to interruption of the corpus callosum
Cause of alexia w/o agraphia
lesion in the dominant occipital cortex extending to the posterior corpus callosum
-most often from PCA infarct
What is apraxia?
Inability to perform learned motor tasks
ex: can’t put a shirt on or salute the flat
What is hemineglect syndrome?
Neglect for the contralateral half of the external world
Most common cause of hemineglect syndrome
Lesions of the right parietal or frontal cortex
-most specifically associated w/ damage to the temporo-parietal junction and posterior parietal cortex
What is limbic encephalitis?
Cause?
Associated w/ what?
Autoimmune inflammation of the brain
-caused by autoimmune often (but not always) associated w/ cancer
Most common presentation of limbic encephalitis
Short term memory deficits
-also psychosis, headache, seizures
What is alien hand syndrome?
(a) where is the lesion?
Involuntary movements of the contralateral arm
(a) lesion of the parietal lobe
