AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 6 884-R887, Copyright © 1984 by American Physiological Society
A discussion of apraxia, aphasia, and gestural language
N. Helm-Estabrooks
It is understood that damage to the left cerebral hemisphere in adulthood
may result in syndromes of language disturbances called the aphasias. The
study of these syndromes sheds light on normal language processes, the
relationship between language behavior and the brain, and how best to treat
aphasic individuals. Aphasia, for some, is a central communication disorder
affecting all symbolic behavior in all modalities (i.e., speech, writing,
and gesture). Difficulty producing symbolic gestures on command is called
apraxia. Others view aphasia as a manifestation of a motor-sequencing
disorder affecting all gestural systems including those required for speech
movements. These divergent theories of the underlying nature of aphasia can
be tested through examination of deaf individuals who use sign language
before onset of aphasia. Poizner et al. [Am. J. Physiol. 246 (Regulatory
Integrative Comp. Physiol. 15): R868-R883, 1984] studied three such
patients with different aphasia syndromes: one patient had a nonsymbolic,
motor-sequencing disorder; one had a gestural apraxia; and one had neither.
These findings force the conclusion that neither the symbolic nor
motor-sequencing theory of aphasia can account for the many varieties of
that disorder.
