The study investigated patterns of intellectual deficit in 13 patients with recently diagnosed Huntington's disease (mean duration of 2.3 years) and 46 offspring "at risk" for the illness using the Wechsler Adult Intelligence Scale (WAIS). The results support the idea that certain cognitive skills remain relatively intact at early stages of the disease while other skills are impaired. A consistent pattern of impairment was observed in the patient group which included the Arithmetic, Digit Span, Digit Symbol, and Picture Arrangement subtests. The most striking result was a demonstration of significantly increased variability among the "at risk" population of the Digit Span and Picture Arrangement subtests. These findings suggest that the WAIS may be a useful adjunct to neurological diagnosis for longitudinal monitoring of intellectual changes even at very early stages of the illness.