Types of Aphasia “Classifications are a necessary evil” Antonio Damasio (1998) Ling 411 – 05

Wernicke’s Aphasia  Impaired comprehension Result of failures in phonological discrimination  Fluent verbal output  Augmented verbal output Extra syllables at ends of words Extra words at ends of phrases Extra phrases at ends of sentences  Augmentations usually nonsensical  Syntax otherwise not too bad  Verbal paraphasia, including neologisms

Areas of damage in Wernicke’s aphasia  Always involved: Posterior superior temporal gyrus  The classical core of Wernicke’s area  Usually also involved: More of superior temporal gyrus middle temporal gyrus Temporal plane  Often also involved: Angular gyrus Supramarginal gyrus Temporal-occipital junction area

Definitions of Wernicke’s area 1. Narrow definition  Posterior superior temporal gyrus 2. Best definition Posterior superior temporal gyrus and adjacent temporal plane and superior temporal sulcus 3.Broad definition (used by some) Includes also angular gyrus and/or supramarginal gyrus A.k.a ‘posterior language area’

Principal cortical gyri (schematic) Review

Subtypes of Wernicke aphasia  Not discretely different Rather, spans along a scale  Type I Damage is more anterior Phonological recognition most affected “Word deafness”  Type II Damage is more posterior, incl. angular gyrus More word-blindness than word-deafness  I.e., alexia  Intermediate types also occur  “Obviously, all subtypes of Wernicke aphasia are variations on a continuum…” (Benson&Ardila:144 )

Extra-Sylvian Aphasic Syndromes  “Extra-Sylvian” (a.k.a. “Transcortical”)  Extrasylvian motor aphasia Type I Type II  Extrasylvian sensory aphasia  Sometimes just called ‘anomic aphasia’ Type I Type II

Two Different Classification Schemes Damasio  Wernicke’s aphasia  Broca’s aphasia  Conduction aphasia  Transcortical sensory aph.  Transcortical motor aph.  Global aphasia  Anomic aphasia  Alexia Benson & Ardila  Wernicke aphasia  Broca aphasia  Conduction aphasia  Extrasylvian sensory aph.  Extrasylvian motor aph.  Global aphasia  Anomic aphasia  Wernicke II or Posterior extrasylvian

Extra-Sylvian Aphasic Syndromes  In all perisylvian syndromes, repetition is faulty  In all extra-sylvian aphasic syndromes, repetition is intact (why?)  “Aphasia without repetition disturbance almost invariably indicates pathology outside the perisylvian region” (B&A 1996:146)

Extrasylvian motor aphasia  Nonfluent output Delayed initiation Terse, poorly elaborated utterances Incomplete sentences Verbal paraphasia  Good comprehension  Good repetition

Extrasylvian motor aphasia, Type I  Left dorsolateral prefrontal damage Anterior and superior to Broca’s area  Non-fluent output, but repetition good  Articulation is normal  Difficulty following commands Understand command but do not respond  Damage anterior and superior to Broca’s area (Brodmann areas 45, 46, and/or part of area 9) (B&A 1996:152)Brodmann areas

Orientation terms (left hemisphere) Dorsal Ventral Rostral Caudal

Extrasylvian motor aphasia, Type II  Damage to supplementary motor area Occlusion of left anterior cerebral artery  Non-fluent output, but good repetition  Difficulty initiating speech  Perhaps a purely motor disorder that does not involve basic language functions (in which case it isn’t really a type of aphasia)

Principal cortical gyri Superior parietal lobule Supplementary motor area

Extrasylvian sensory aphasia  Speech is fluent  Good repetition  Comprehension is impaired  Naming is impaired  Paraphasia is frequent, even verbose Semantic substitutions Neologisms  Echolalia (patients repeat words of examiner)  Pointing is impaired  Two subtypes

Extrasylvian sensory aphasia, Type I  Damage to temporal-parietal-occipital junction area I.e., lower angular gyrus and upper area 37area 37  Fluent spontaneous output  Poor comprehension  Naming strongly impaired  Semantic paraphasia

Extrasylvian sensory aphasia, Type II  Damage to upper angular gyrus  Fluent output  Variable ability to comprehend speech  Naming strongly impaired  Few semantic paraphasias  Repetition excellent  Many circumlocutions

Anomic aphasia  Perhaps part of a continuum with extrasylvian sensory aphasia  Comprehension is good in many cases Unlike extrasylvian sensory aphasia  Production and repetition are good  Cannot be reliably localized Many different areas of damage can result in naming difficulty  But different semantic categories may be impaired with different areas of damage Maybe not a true syndrome: Benson&Ardila

end