Chapter 027. Aphasia, Memory Loss, and Other Focal Cerebral Disorders (Part 4)

Gestures and pantomime do not improve communication. The patient does not seem to realize that his or her language is incomprehensible and may appear angry and impatient when the examiner fails to decipher the meaning of a severely paraphasic statement. In some patients this type of aphasia can be associated with severe agitation and paranoid behaviors. One area of comprehension that may be preserved is the ability to follow commands aimed at axial musculature. The dissociation between the failure to understand simple questions ("What is your name?") in a patient who rapidly closes his or her eyes, sits up,...
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Chapter 027. Aphasia, Memory Loss, and Other Focal Cerebral Disorders (Part 4) Chapter 027. Aphasia, Memory Loss, and Other Focal Cerebral Disorders (Part 4) Gestures and pantomime do not improve communication. The patient doesnot seem to realize that his or her language is incomprehensible and may appearangry and impatient when the examiner fails to decipher the meaning of a severelyparaphasic statement. In some patients this type of aphasia can be associated withsevere agitation and paranoid behaviors. One area of comprehension that may bepreserved is the ability to follow commands aimed at axial musculature. Thedissociation between the failure to understand simple questions (What is yourname?) in a patient who rapidly closes his or her eyes, sits up, or rolls over whenasked to do so is characteristic of Wernickes aphasia and helps to differentiate itfrom deafness, psychiatric disease, or malingering. Patients with Wernickesaphasia cannot express their thoughts in meaning-appropriate words and cannotdecode the meaning of words in any modality of input. This aphasia therefore hasexpressive as well as receptive components. Repetition, naming, reading, andwriting are also impaired. The lesion site most commonly associated with Wernickes aphasia is theposterior portion of the language network and tends to involve at least parts ofWernickes area. An embolus to the inferior division of the middle cerebral artery,and to the posterior temporal or angular branches in particular, is the mostcommon etiology (Chap. 364). Intracerebral hemorrhage, severe head trauma, orneoplasm are other causes. A coexisting right hemi- or superior quadrantanopia iscommon, and mild right nasolabial flattening may be found, but otherwise theexamination is often unrevealing. The paraphasic, neologistic speech in an agitatedpatient with an otherwise unremarkable neurologic examination may lead to thesuspicion of a primary psychiatric disorder such as schizophrenia or mania, but theother components characteristic of acquired aphasia and the absence of priorpsychiatric disease usually settle the issue. Some patients with Wernickes aphasiadue to intracerebral hemorrhage or head trauma may improve as the hemorrhageor the injury heals. In most other patients, prognosis for recovery is guarded. Brocas Aphasia Speech is nonfluent, labored, interrupted by many word-finding pauses, andusually dysarthric. It is impoverished in function words but enriched in meaning-appropriate nouns and verbs. Abnormal word order and the inappropriatedeployment of bound morphemes (word endings used to denote tenses,possessives, or plurals) lead to a characteristic agrammatism. Speech is telegraphicand pithy but quite informative. In the following passage, a patient with Brocasaphasia describes his medical history: I see . . . the dotor, dotor sent me . . .Bosson. Go to hospital. Dotor . . . kept me beside. Two, tee days, doctor send mehome. Output may be reduced to a grunt or single word (yes or no), which isemitted with different intonations in an attempt to express approval or disapproval.In addition to fluency, naming and repetition are also impaired. Comprehension ofspoken language is intact, except for syntactically difficult sentences with passivevoice structure or embedded clauses. Reading comprehension is also preserved,with the occasional exception of a specific inability to read small grammaticalwords such as conjunctions and pronouns. The last two features indicate thatBrocas aphasia is not just an expressive or motor disorder and that it may alsoinvolve a comprehension deficit for function words and syntax. Patients withBrocas aphasia can be tearful, easily frustrated, and profoundly depressed. Insightinto their condition is preserved, in contrast to Wernickes aphasia. Even whenspontaneous speech is severely dysarthric, the patient may be able to display arelatively normal articulation of words when singing. This dissociation has beenused to develop specific therapeutic approaches (melodic intonation therapy) forBrocas aphasia. Additional neurologic deficits usually include right facialweakness, hemiparesis or hemiplegia, and a buccofacial apraxia characterized byan inability to carry out motor commands involving oropharyngeal and facialmusculature (e.g., patients are unable to demonstrate how to blow out a match orsuck through a straw). Visual fields are intact. The cause is most often infarctionof Brocas area (the inferior frontal convolution; B in Fig. 27-1) and surroundinganterior perisylvian and insular cortex, due to occlusion of the superior division ofthe middle cerebral artery (Chap. 364). Mass lesions including tumor, intracerebralhemorrhage, or abscess may also be responsible. ...