Early cognitive deficits in Swedish gene carriers of Huntington's disease.

The primary focus of this study was to examine whether there is early neuropsychological impairment in presymptomatic Huntington's disease (HD). A broad neuropsychological assessment battery was administered to 24 asymptomatic gene carriers (HD+) and 31 noncarriers (HD-). The gene carriers revealed inferior cognitive functioning as compared with the noncarriers in memory and executive functions. When the gene carriers were assigned to 2 groups based on predicted years to onset (with 15 and over being HD+ late and under 15 being HD+ near), the HD+ near group performed significantly worse than the HD+ late group in all domains but ability to shift conceptually and visuospatial memory. Results suggest that early cognitive deficits are detectable prior to motor symptoms, first in memory functions and then in executive functions and perceptual motor speed.