ABSTRACT
The possibility of a sign language aphasia has long fascinated researchers of the mind. In 1878 Hughlings Jackson wrote, “No doubt by disease of some part of his brain the deaf-mute might lose his natural system of signs” (p. 304). Since this time, numerous case studies have provided evidence to support this claim. Cross-modality comparisons of human language provide some of the strongest evidence to date for biological determination of human language. These studies provide keen insight into the determination of hemispheric specialization, neural plasticity, and the contribution of symbolic, motoric, and linguistic processes in human language. Investigations of sign language aphasia require an understanding of deafness, of the structure of sign languages, and of language competence in hearing-impaired individuals. This chapter provides an overview of these issues and explores the theoretical implications of some recent studies. The aim of this chapter is to document the current status of the field and to foreshadow issues that are likely to be of interest in future studies. Where possible, results from signing individuals are compared to neuropsychological results from nondeaf patients. Previous reviews can also be found in Kimura (1981), Poizner, Klima, and Bellugi (1987), and Poizner and Kegl (1992).
