Neuropsychological and neuroradiological study of a case of early-onset Huntington's chorea.

The authors report a case of Huntington's disease in an 11-year-old boy with onset at six years of age. The neurological signs and symptoms were midway between the hyperkinetic and rigid forms of chorea. Intellectual development was characterized by a medium-grade deficit. MRI revealed marked atrophy of the head of the caudate nucleus, with diffuse hyperintensity of the putamen. The most characteristic neuropsychological feature was ideomotor apraxia. Neuropsychological and neuroradiological data are discussed in relation to the role of the basal nuclei and frontal cortex in the organization of movement.