Neuropsychological performance.

All values represent mean (SD). Between-groups comparisons have been investigating using univariate analysis of variance for each variable, with age, disease duration and Led as covariates and group membership (apathy vs. No apathy) as fixed factor (ANCOVA). The η2 statistic was used to estimate the effect size. P <0.05, FDR corrected. D-KEFS = Delis-Kaplan Executive Function system; CVLT-II = California Verbal Learning Test –II; WCST-64 = Wisconsin Card Sorting Test-64 cards version; SS = Spatial Span; DS = Digit Span; DSy = Digit symbol.