Behavioral effects of damage to the right insula and surrounding regions.

A severe multimodal neglect syndrome, mutism, oral apraxia and ideomotor apraxia for the right hand suddenly developed in a right-handed male following a right hemisphere (central) stroke. Neuropathologic examination showed an ischemic infarction involving the whole right insula, adjacent white matter, and the inner cortical surface of the right fronto-temporo-parietal operculum. The left hemisphere was spared. It is suggested that damage to the right insula (a polymodal convergence area), and the adjacent white matter may lead to severe neglect. Our case also demonstrates a clear dissociation between dominance for handedness and dominance for kinesthetic motor engrams.