Fig. 1.

Frequency of WM/EF impairment in MCI and AD groups. Distribution of z scores between groups for each of the tests. Each dot in the graphs represents a subject. P values have been obtained through χ² tests comparing the proportion of subjects below and above −1 z score between groups. Bonferroni adjustment for level of significance was set at P = .004. Note that there was a trend to significance in the comparison of EHC and MCI on digits backward (P = .009). Abbreviations: EHC, elderly healthy controls; MCI, mild cognitive impairment; AD, Alzheimer's disease; P, P value.