Discourse Deficits Following Right Hemisphere Damage in Deaf Signers

Previous findings have demonstrated that hemispheric organization in deaf users of American Sign Language (ASL) parallels that of the hearing population, with the left hemisphere showing dominance for grammatical linguistic functions and the right hemisphere showing specialization for non-linguistic spatial functions. The present study addresses two further questions: first, do extra-grammatical discourse functions in deaf signers show the same right-hemisphere dominance observed for discourse functions in hearing subjects; and second, do discourse functions in ASL that employ spatial relations depend upon more general intact spatial cognitive abilities? We report findings from two right-hemisphere damaged deaf signers, both of whom show disruption of discourse functions in absence of any disruption of grammatical functions. The exact nature of the disruption differs for the two subjects, however. Subject AR shows difficulty in maintaining topical coherence, while SJ shows difficulty in employing spatial discourse devices. Further, the two subjects are equally impaired on non-linguistic spatial tasks, indicating that spared spatial discourse functions can occur even when more general spatial cognition is disrupted. We conclude that, as in the hearing population, discourse functions involve the right hemisphere; that distinct discourse functions can be dissociated from one another in ASL; and that brain organization for linguistic spatial devices is driven by its functional role in language processing, rather than by its surface, spatial characteristics.

[1]  Elissa L. Newport,et al.  The acquisition of American Sign Language. , 1985 .

[2]  M. Farah,et al.  Behavioral Neurology and Neuropsychology , 1996 .

[3]  H Poizner,et al.  Neural Disorders of the Linguistic Use of Space and Movement a , 1993, Annals of the New York Academy of Sciences.

[4]  Karen Emmorey,et al.  Processing spatial anaphora: Referent reactivation with overt and null pronouns in american sign language , 1995 .

[5]  Elisabeth Engberg-Pedersen,et al.  Space in Danish sign language : the semantics and morphosyntax of the use of space in a visual language , 1993 .

[6]  W. Sandler,et al.  On the nature of phonological structure in sign language , 1993, Phonology.

[7]  Diane C. Lillo-Martin,et al.  Universal Grammar and American Sign Language: Setting the Null Argument Parameters , 1991 .

[8]  David M. Perlmutter.  SONORITY AND SYLLABLE STRUCTURE IN AMERICAN SIGN LANGUAGE , 1993 .

[9]  Ursula Bellugi,et al.  The neurobiology of sign language and its implications for the neural basis of language , 1996, Nature.

[10]  U. Bellugi,et al.  What the hands reveal about the brain , 1987 .

[11]  R. Knight,et al.  Aphasia in a prelingually deaf woman. , 1982, Brain : a journal of neurology.

[12]  Scott K. Liddell.  American Sign Language Syntax , 1981 .

[13]  城所 良明,et al.  The Salk Institute for Biological Studies(話題) , 1975 .

[14]  L. Bérubé,et al.  [Clinical neuropsychology]. , 1982, Nursing Quebec.

[15]  H. Gardner,et al.  Inference deficits in right brain-damaged patients , 1986, Brain and Language.

[16]  A. Benton,et al.  Visuoperceptual, visuospatial, and visuoconstructive disorders. , 1993 .

[17]  U. Bellugi,et al.  Language, modality and the brain , 1989, Trends in Neurosciences.

[18]  H. Gardner,et al.  The role of the right hemisphere in the apprehension of complex linguistic materials , 1981, Brain and Language.

[19]  E. Klima.  The signs of language , 1979 .

[20]  R. J. Frank,et al.  Three-dimensional in vivo mapping of brain lesions in humans. , 1992, Archives of neurology.

[21]  D. Slobin.  The Crosslinguistic Study of Language Acquisition , 1987 .

[22]  G. Edelman,et al.  Signal and sense : local and global order in perceptual maps , 1990 .