The Wisconsin Card Sorting Test and the N-back test in mild cognitive impairment and elderly depression.

The aim of this study was to assess cognitive functions in 30 non-depressed patients with mild cognitive impairment (MCI), compared with 30 age-, gender- and education-matched patients with acute depressive episode, and with 30 healthy subjects. Neuropsychological assessment included the Mini Mental State Examination (MMSE), memory tests as well as the Wisconsin Card Sorting Test (WCST) and the N-back test. Patients with MCI obtained significantly worse results on all domains of the WCST and the N-back test compared to both depressed and healthy subjects. Depressed patients showed significantly worse performance than controls on most scores. In the MCI group, no association with MMSE was found with any of WCST domains, or with reaction time in the N-back test. Three tests, WCST-P, N-back %CORR and WCST 1st CAT obtained highest ranks (>90) as predictors for differentiating between groups. The results suggest a usefulness of employing WCST and N-back tests for a neuropsychological evaluation of patients with MCI.