Construct validity of the WCST in normal elderly and persons with Parkinson's disease

Separate principle component analyses of the WCST were conducted on 187 normal elderly and 181 persons with Parkinson's disease (PD). Adequate construct validity was found for "conceptualization/problem solving" and "failure to maintain set" factors in both groups. Perseverative and nonperseverative errors were related for the normal group, but not for the PD subjects. This may reflect the frontal systems deficit observed in PD. Additional principle component analyses were conducted with the WCST and measures of memory and attention. In neither the normal nor the PD group did the WCST significantly load with the memory and attention measures. This suggests that the WCST provides information about problem solving relatively independent of memory and attention functions for elderly persons.