Factor Structure of a Modified Version of the Wisconsin Card Sorting Test: An Analysis of Executive Deficit in Alzheimer’s Disease and Mild Cognitive Impairment

In order to explore the factor structure of a modified version of the Wisconsin Card Sorting Test (mWCST) and to identify the dimensions of deficit in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI), conventional mWCST scores in 55 AD patients, 17 MCI patients, and 22 controls were subjected to factor analysis. Three factors, perseveration, inefficient sorting, and nonperseverative error, were obtained. Perseveration score was significantly poorer in both AD and MCI than in controls. By contrast, the MCI group showed significantly poorer scores on the nonperseverative error factor than did the AD patients, and the controls yielded intermediate values between the two patient groups. The perseveration factor was significantly correlated with the other estimates of executive function. This study suggested that the many mWCST scores could be reduced to three major factors, and that the perseveration score may effectively represent an aspect of executive dysfunction in AD and MCI patients.