Aphasia in a Prelingually Deaf Woman

Abstract

A left parietal infarct in a prelingually deaf person resulted in an aphasia for both American Sign Language (ASL) and written and finger-spelled English. Originally the patient had a nearly global aphasia affecting all language systems. By five to seven weeks post-onset her symptoms resembled those of hearing aphasics with posterior lesions: fluent but paraphasic signing, anomia, impaired comprehension and repetition, alexia, and agraphia with elements of neologistic jargon. In addition, there was a pronounced sequential movement copying disorder, reduced short-term verbal memory and acalculia. In general, the patient's sign errors showed a consistent disruption in the structure of ASL signs which parallels the speech errors of oral aphasic patients. We conclude that most aphasic symptoms are not modality-dependent, but rather reflect a disruption of linguistic processes common to all human languages. This case confirms the importance of the left hemisphere in the processing of sign language. Furthermore, the results indicate that the left supramarginal and angular gyri are necessary substrates for the comprehension of visual/gestural languages.

Biological Foundations of Language: Clues from Sign Language

“…Although it is clear that lesions in the left but not in the right hemisphere produce sign language aphasias, different areas within the left hemisphere may mediate language in the two modes. There are increasing reports of lesions to the parietal lobe of the left hemisphere that produce aphasias for sign language that would not be predicted for a hearing individual with that lesion (Poizner et al 1987, Chiarello et al 1982. It may well turn out that areas of the left hemisphere more intimately involved with gestural control and higher order spatial analysis emerge as language-mediating areas for sign language.…”

Cross-Linguistic Differences in the Neural Representation of Human Language: Evidence from Users of Signed Languages

“…It is noteworthy that the cases described by Chiarello et al (1982) and Poizner et al (1987) and the case study described by Corina et al (1992), exhibited fluent aphasia with severe comprehension deficits. Lesions in these case studies did not occur in cortical Wernicke’s area proper, but rather involved more frontal and inferior parietal areas.…”

“…This is interesting, as lesions associated with the supramarginal gyrus alone in users of spoken language do not typically result in severe speech comprehension deficits. These observations have led some to suggest that sign language comprehension may be more dependent than speech on left-hemisphere inferior parietal areas, that is, regions associated with somatosensory and visual motor integration (Leischner, 1943; Chiarello et al, 1982; Poizner et al, 1987; Corina, 1998a,b), while spoken language comprehension might depend more heavily on posterior temporal lobe association regions whose input includes networks intimately involved with auditory speech processing. Currently the lack of an adequate number of well-described case studies limits our ability to revolve this controversy.…”

Discourse Deficits Following Right Hemisphere Damage in Deaf Signers

“…2A) and deficits in performing non-linguistic visuospatial tasks (often seen in RHD signers and rarely in LHD signers, see Fig. 2B) (Chiarello, Knight, & Mandel, 1982;Hickok, Klima, Kritchevsky, & Bellugi, 1995;Hickok, Klima, & Bellugi, 1996;Poizner & Kegl, 1993;Poizner, Klima, & Bellugi, 1987). Note the rating scale profile of sign language characteristics based on the Salk Sign Diagnostic Aphasia Examination for three groups of signers shown in Fig.…”