Aphasia/Dysarthria

Aphasia/Dysarthria: Excerpt from Field Guide to Bedside Diagnosis

Differential Overview

Aphasia (Central)

❑ Broca

❑ Wernicke

❑ Conduction

❑ Anomic

❑ Global

❑ Motor aphasia

❑ Pure word deafness

❑ Alexia without agraphia

❑ Alexia with agraphia

Dysarthria (Peripheral)

❑ Bulbar

❑ Parkinson

❑ Multiple sclerosis

❑ Tongue infiltration

Diagnostic Approach

Clinical Findings

Broca  Occlusion of the superior middle cerebral artery affects the precentral gyrus, responsible for the motor part of language production. Speech is telegraphic, produced with great effort, with abnormal word order, abnormal tense use, and the omission of small words or endings, yet it is understandable. Comprehension of written or verbal speech is good. The patient is aware of the deficit and is frustrated. Hemiparesis is usually present because Broca area is adjacent to the motor cortex.

Wernicke  It involves the primary auditory cortex for understanding of auditory input and monitoring of speech output. Speech is fluent with normal rhythm but conveys information poorly because of circumlocutions and paraphrasic errors (“jargon aphasia”). Comprehension, repetition, and object naming are poor. The patient may be able to repeat long, complex sentences. Writing content is abnormal although penmanship may be good. Patients may not realize their deficit. There are usually no motor deficits, but a hemianopsia or quadrantanopsia may be present.

Conduction  Abnormalities result from an angular gyrus lesion, the center for integrating sensory and other associated information, often caused by a “watershed” infarct due to hypoperfusion. Speech is fluent but conveys information imperfectly, with frequent literal paraphrasic errors (fish for dish). The patient can comprehend spoken and written language but has difficulty reading aloud (although comprehension is good with silent reading). Repetition, object naming, and writing are poor. The patient may have dysgraphia (ranging from minor misspellings to agraphia), buccofacial apraxia, mild right hemiparesis, and hemisensory deficit.

Anomic  This type of aphasia arises from a metabolic disorder or space-
ccupying lesion with pressure effect. Speech is fluent but conveys information poorly. The patient can understand both written and spoken speech and can repeat normally. There are no motor deficits.

Global  In a large middle cerebral artery infarct, hemiparesis occurs along with inability to comprehend or speak.

Motor aphasia  Frontal lobe speech is nonfluent with preserved comprehension like Broca, but repetition of complex sentences is preserved. Upper extremity weakness (proximal greater than distal) is present.

Pure word deafness  This is caused by bilateral temporal lobe or a single, deep, left temporal lobe lesion. The patient is unable to understand spoken words, but hearing is intact, and the patient can read aloud.

Alexia without agraphia  The patient can comprehend spoken words and tracings on the palm but cannot read. He or she can write, then cannot read it. The lesion is in the splenium of the corpus callosum plus the left visual cortex.

Alexia with agraphia  A lesion of the dominant angular gyrus produces Gerstmann syndrome (finger agnosia, right-to-left disorientation, acalculia, agraphia) plus anomia and constructional apraxia.

Bulbar  Weakness of the lips, tongue, and larynx produce a decreased ability to pronounce consonants. Causes include Guillain-Barré syndrome, polio, posterior fossa meningitis (syphilis or carcinomatous), and posterior inferior cerebellar ischemia.

Parkinson  Speech is thick and slow without normal modulations.

Multiple sclerosis  Speech is “scanning,” pronouncing syllable by syllable.

Tongue infiltration  Thick speech may be caused by cancer of the tongue, angioedema, or amyloidosis.

Pictures

Book Source Details

• Book Title: Field Guide to Bedside Diagnosis
• Author(s): David S. Smith
• Year of Publication: 2007
• Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2007 Lippincott Williams & Wilkins.

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More About This Book: Title: Field Guide to Bedside Diagnosis Authors: David S. Smith Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 0-78178-165-5

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