Dominant posterior-variant alien hand syndrome after acute left parietal infarction.

Alien hand syndrome (AHS) is a complex clinical disorder in which patients develop a sense of estrangement from, and loss of volitional control of, an affected limb and non-purposeful complex motor actions of the same limb. Several forms of AHS exist, including frontal, callosal, and posterior types with a series of different associated neuroanatomical lesions and clinical symptoms. Most commonly, the lesions associated with AHS occur in the frontal lobes and corpus callosum. Rarely, lesions in the parietal lobes may be associated with AHS, and most often occur within the non-dominant hemisphere. We describe a 57-year-old patient who developed symptoms of posterior AHS after an acute infarction in the left (presumably dominant) parietal lobe. A review of the different clinical features of AHS and the underlying mechanisms is also presented.