Sub-cortical aphasia Syndromes

Abstract

Aphasia has traditionally been described as a language disorder resulting from damage to the cerebral cortex. The classical models of language function, based on post-mortem findings, proposed by Wernicke (1874) and Lichtheim (1885) predicted that sub-cortical lesions could only produce language deficits if they disrupted the association pathways that connect the various cortical language centres. Such disruption has been suggested to cause conduction aphasia (Geschwind, 1965a,b; Damasio et al.,1979). In recent times, however, the belief that the cortex operates as a closed neuronal circuit responsible for language functioning has been challenged by a number of authors (Ojemann, 1976; Kornhuber, 1977; Brunner et al., 1982; Glosser, Kaplan and LoVerme, 1982).