Table 1.

Demographic and behavioral results for healthy control and early-stage AD groups with t-tests for significant differences between groups

Characteristics	Alzheimer's disease	Healthy control	P-value
Age	74.9 (7.4)	74.2 (7.1)	NS
Education	14.4 (2.9)	15.5 (2.4)	NS
MMSE∗	24.6 (2.7)	29.1 (0.9)	<0.01
% Correct on ERP task†	91.2 (15.7)	99.0 (1.8)	<0.0001

Abbreviations: AD, Alzheimer's disease; ERP, event-related potential.

NOTE. Values appear as mean (SD) unless otherwise indicated. The age and education information is in number of years. AD and healthy control groups each contained 18 women and 18 men, totaling 36 participants.

^∗MMSE = Mini-Mental State Examination [11] (maximum of 30 points, where higher scores indicate greater cognitive functioning). Neuropsychological test results are in Supplementary 1.

^†Number of correctly answered trials divided by the total number of trials (204) in our number-letter paradigm (median [interquartile range]). Only correct trials were used in subsequent ERP analyses.