Aphasias: Language Disturbances Associated with Brain Injury
The Classic View:
based on symptoms and associated with particular brain areas
The Major Syndromes:
Broca’s aphasia
Wernicke’s aphasia Conduction aphasia
Broca’s Aphasia
Sparse halting speech
Understanding relatively intact
BUT cannot understand sentences like
“The cow that was eating the apple was red”
Most function words and inflections omitted
Lesion Site: Posterior portion of left frontal lobe
Cognitive Deficit: speech planning and production AND
parsing
Sample of Speech for Broca’s Aphasia
Attempting to describe when he had his stroke, which
occurred when he was in a hot tub
Alright…uh…stroke and un…I…h…hot tub and…And
the…Two days when uh…Hos…uh…hospital and uh..
am…ambulance
Wernicke’s Aphasia
Poor auditory comprehension
Fluent speech but morphological and semantic errors
Lesion Site: Posterior half of temporal cortex
Cognitive Deficit
Accessing lexemes for comprehension and production
Sample:
Wernicke’s
aphasia
Conduction Aphasia
Relatively rare
Disturbance of repetition (with awareness)
Mild disturbance of spontaneous speech
Lesion area: Arcuate fasciculus
but more recent analysis questions this
Cognitive deficit:
Disconnection of lexemes from speech production mechanisms
Cognitive Model Analysis of Speech Processing
Pure word deafness
Pure word meaning deafness
Auditory phonological agnosia
Deep dysphasis
Cognitive Model Analysis of Written Word
Processing (Reading)
Surface dyslexia
Phonological dyslexia
Deep dyslexia
Cognitive Model Analysis of Auditory Speech Processing
Pure word deafness
can talk & read fluently
can’t repeat words they can’t understand
can’t understand speech addressed to them
Impairment = phonemic processing in the auditory analysis system
Pure Word Meaning Deafness
Can’t understand what words mean when spoken
Can repeat words
Can write words from dictation
Can decide what is really a word
Impairment = connection between the auditory lexicon & semantic system
Auditory Phonological Agnosia
Can read aloud & write well
Can’t repeat non-words or words not heard before
Impairment = direct route for repetition via auditory analysis system
Deep Dysphasia
Can’t repeat non-words
Makes semantic errors when repeating back real words
Impairment = access to semantics from auditory input lexicon &
direct route from auditory analysis system
Cognitive Model Analysis of Processing Written Speech
Surface Dyslexia
Able to read words if they are regular in their spelling
Can read non-words
Impairment = Visual input lexicon
Case: William
Phonological Dyslexia
Can read familiar words
Has difficulty with non-words & novel words
Impairment = grapheme-phoneme conversion
Case: Ann
Deep Dyslexia
Semantic errors