Hemispheric control of speech expression in aphasia. A mouth asymmetry study
R. Graves and T. Landis
Clinical observation of aphasic patients often shows a dissociation between
impaired propositional speech and preserved automatic speech. The question
of differing hemispheric control between these speech tasks was examined by
measuring asymmetry in facial muscle activity. In spite of right-sided
facial palsy, greater opening of the right side of the mouth was seen for
spontaneous speech, repetition, and word list generation, suggesting that
the damaged left hemisphere still controlled motor output in these
propositional tasks. However, greater opening of the left side of the mouth
for serial speech and singing indicated at least a relatively greater role
of the right hemisphere in these "automatic" tasks.
