AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 6 868-R883, Copyright © 1984 by American Physiological Society
Apraxia and aphasia for a visual-gestural language
H. Poizner, U. Bellugi and V. Iragui
Since signed languages utilize visual-gestural channels, their study allows
a unique opportunity for insight into the ways language and gesture may be
represented in the brain. The separability of apraxia and aphasia for sign
language was examined in four deaf signers who had unilateral brain damage,
three to the left hemisphere and one to the right hemisphere. These
patients were administered various tests for apraxia and a test of
pantomime recognition. The patient with damage to the right hemisphere was
not apraxic as we would expect. For the patients with damage to the left
hemisphere, all of whom were aphasic for sign language, strong
dissociations emerged between their capacities for sign language and their
nonlinguistic motor skills. The language deficits of these patients seemed
related to specific linguistic components of sign language rather than to
an underlying motor disorder or an underlying disorder in the capacity to
express and comprehend symbols of any kind. This separation between
linguistic and nonlinguistic function is all the more striking, because
sign language and gesture are transmitted in the same modality.
