Morphologic agrammatism following a right hemisphere stroke in a dextral patient.
There is evidence of two major components of grammatic function in the brain: (1) morphologic, probably based in the postcentral perisylvian cortex, encompassing the selection of individual words and inflectional endings according to the rules of grammar; and (2) syntactic, probably based in the frontal lobes, encompassing construction of the overall structure of a sentence (syntax) to match the concept being considered. We present a stroke patient with impaired morphology but, unlike Broca's aphasics, relative sparing of syntax. He omitted 43% of articles, 40% of complementizers, 20% of pronouns, 27% of semantically marked prepositions, 43% of purely grammatic prepositions, and 22% of auxiliary verbs, but his average sentence length was 9.8 words and 64% of his sentences contained embedded clauses. He frequently intermingled two sentences to convey a given concept, juxtaposing words in grammatically unacceptable ways. This intermingling may represent either a grammatic "conduite d'approche," or a failure of the filtering function of a defective morphologic processor. His great difficulty in completing syntactic frames suggests that a more general form of the processes underlying grammatic morphology may play an important role in phrase structure generation.
Nadeau
S E
SE
GRECC-182, Department of Veterans Affairs Medical Center, Gainesville, FL 32608-1197.
Rothi
L J
LJ
D000368:Aged; D000849:Anomia / Q000175:diagnosis / Q000209:etiology; D001041:Aphasia, Wernicke / Q000175:diagnosis / Q000209:etiology; D001921:Brain / Q000503:physiopathology; D001927:Brain Diseases / Q000150:complications / Q000503:physiopathology; D002561:Cerebrovascular Disorders / Q000150:complications*; D007839:Functional Laterality; D006801:Humans; D007806:Language Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D007807:Language Tests; D008297:Male; D009483:Neuropsychological Tests