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-y ear-old white female without history of familial sinistrality or prior neurological illness. She developed a right middle cerebral artery in farction documented by CT and accompanied by obvious clinical signs of a conduction aphasia with some resolution but continuing obvious lang uage defect after 9 weeks in rehabilitation. Comprehensive neuropsycho logical and aphasia testing suggested anomalous lateralization of phon ologic-output aspects of language, emotional prosody, motor planning a nd body schema modules with usual lateralization of lexical-semantic a spects of language and visuo-spatial functions. Experimental validatio n of the uncrossed lexical-semantic aspects of language using tachisto scope methods found support for the Alexander-Annett theory that diffe rent aspects of language can be dissociated in their lateralization. T he subject had difficulty identifying a semantic associate of a pictur e presented to the left visual field (7 errors out of 10) relative to right visual field presentation (2 errors out of 10). Bilateral free n aming errors (6 and 5 errors in the left and right visual fields, resp ectively) occurred consistent with the aphasic presentation, suggestin g phonologic-output dysfunction from the right cerebral vascular accid ent. Implications of the results for aphasia classification are discus sed. (C) 1998 Academic Press.