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)

Orientation terms (left hemisphere)

Dorsal

Ventral

RostralCaudal

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 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

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