Posterior alien hand syndrome after a right thalamic infarct.

The alien hand syndrome, as originally defined, should be reserved for cases in which the hand feels foreign "together with" observable involuntary motor activity. These involuntary movements are unusual during or after acute stroke. Three varieties of alien hand syndrome have been reported, involving lesions of the corpus callosum alone, the corpus callosum plus dominant medial frontal cortex, and posterior cortical and subcortical areas. A patient with posterior alien hand syndrome of vascular aetiology is reported. Imaging studies disclosed an isolated infarction of the right thalamus sparing other cerebral regions.