Chapter 027. Aphasia, Memory Loss, and Other Focal Cerebral Disorders (Part 3)

The correspondence between individual deficits of language function and lesion location does not display a rigid one-to-one relationship and should be conceptualized within the context of the distributed network model. Nonetheless, the classification of aphasias of acute onset into specific clinical syndromes helps to determine the most likely anatomic distribution of the underlying neurologic disease and has implications for etiology and prognosis (Table 27-1). The syndromes listed in Table 27-1 are most applicable to aphasias caused by cerebrovascular accidents (CVA). They can be divided into "central" syndromes, which result from damage to the two epicenters of the language network...
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Chapter 027. Aphasia, Memory Loss, and Other Focal Cerebral Disorders (Part 3) Chapter 027. Aphasia, Memory Loss, and Other Focal Cerebral Disorders (Part 3) The correspondence between individual deficits of language function andlesion location does not display a rigid one-to-one relationship and should beconceptualized within the context of the distributed network model. Nonetheless,the classification of aphasias of acute onset into specific clinical syndromes helpsto determine the most likely anatomic distribution of the underlying neurologicdisease and has implications for etiology and prognosis (Table 27-1). Thesyndromes listed in Table 27-1 are most applicable to aphasias caused bycerebrovascular accidents (CVA). They can be divided into central syndromes,which result from damage to the two epicenters of the language network (Brocasand Wernickes areas), and disconnection syndromes, which arise from lesionsthat interrupt the functional connectivity of these centers with each other and withthe other components of the language network. The syndromes outlined below areidealizations; pure syndromes occur rarely. Table 27-1 Clinical Features of Aphasias and Related Conditions Comprehe Repeti Nami Fluennsion tion of ng cy Spoken Language Wernickes Impair Impai Impai Preser ed red red ved or increased Brocas Preserv Impai Impai Decre ed (except red red ased grammar) Global Impair Impai Impai Decre ed red red ased Conduction Preserv Impai Impai Preser ed red red ved Nonfluent Preserv Preser Impai Impair(motor) ed ved red edtranscortical Fluent Impair Preser Impai Preser(sensory) ed ved red vedtranscortical Isolation Impair Echol Impai No ed alia red purposeful speech Anomic Preserv Preser Impai Preser ed ved red ved except for word- finding pauses Pure word Impair Impai Preser Preserdeafness ed only for red ved ved spoken language Pure alexia Impair Preser Preser Preser ed only for ved ved ved reading Wernickes Aphasia Comprehension is impaired for spoken and written language. Languageoutput is fluent but is highly paraphasic and circumlocutious. The tendency forparaphasic errors may be so pronounced that it leads to strings of neologisms,which form the basis of what is known as jargon aphasia. Speech contains largenumbers of function words (e.g., prepositions, conjunctions) but few substantivenouns or verbs that refer to specific actions. The output is therefore voluminousbut uninformative. For example, a patient attempts to describe how his wifeaccidentally threw away something important, perhaps his dentures: We dontneed it anymore, she says. And with it when that was downstairs was my teeth-tick. . . a . . . den . . . dentith . . . my dentist. And they happened to be in that bag . . .see? How could this have happened? How could a thing like this happen. . .So shesays we wont need it anymore. . .I didnt think wed use it. And now if I have anyproblems anybody coming a month from now, 4 months from now, or 6 monthsfrom now, I have a new dentist. Where my two . . . two little pieces of dentist thatI use . . . that I . . . all gone. If she throws the whole thing away . . . visit somefriends of hers and she cant throw them a ...