Disturbance of "extrinsic alertness" in Huntington's disease.

Neuropsychological deficits are a main feature of Huntington's disease (HD) with previous data suggesting involvement of attentional functions. Attention can be divided into several different dimensions: intensity, selectivity and supervisory attentional control. These different aspects of attention were investigated in a group of 13 patients with HD and 13 healthy matched control subjects. HD patients were impaired mostly for the intensity dimension: contrary to controls, and like other neurological patient groups, they were not able to speed up their reaction times when an auditory warning stimulus preceded a visual target which suggests a deficit in 'extrinsic alertness.' In addition less severe impairments were found in the dimensions selectivity and supervisory attentional control.