Crossed aphasia in a dextral: a test of the Alexander-Annett theory of anomalous organization of brain function.
A case of crossed aphasia is presented in a strongly right-handed 77-year-old white female without history of familial sinistrality or prior neurological illness. She developed a right middle cerebral artery infarction documented by CT and accompanied by obvious clinical signs of a conduction aphasia with some resolution but continuing obvious language defect after 9 weeks in rehabilitation. Comprehensive neuropsychological and aphasia testing suggested anomalous lateralization of phonologic-output aspects of language, emotional prosody, motor planning and body schema modules with usual lateralization of lexical-semantic aspects of language and visuo-spatial functions. Experimental validation of the uncrossed lexical-semantic aspects of language using tachistoscope methods found support for the Alexander-Annett theory that different aspects of language can be dissociated in their lateralization. The subject had difficulty identifying a semantic associate of a picture presented to the left visual field (7 errors out of 10) relative to right visual field presentation (2 errors out of 10). Bilateral free naming errors (6 and 5 errors in the left and right visual fields, respectively) occurred consistent with the aphasic presentation, suggesting phonologic-output dysfunction from the right cerebral vascular accident. Implications of the results for aphasia classification are discussed.
Department of Psychology, University of Wisconsin-Milwaukee 53211, USA. neuropsy@csd.uwm.edu
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Osmon
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Panos
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Kautz
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Gandhavadi
D000368:Aged; D001037:Aphasia / Q000175:diagnosis / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D009483:Neuropsychological Tests