TABLE 3.

Impact of practice effects on classification stability and progression.

	Stable M MCI	Stable S MCI	Progression to M MCI	Stable impairment
				Memory	Attention/EF	Language
Unadjusted	45	147	34	201	46	42
Adjusted	49	164	37	223	48	44
Difference	+4	+17	+3	+22	+2	+2
% difference	8.89%	11.56%	8.82%	10.94%	4.35%	4.76%
χ2; p-value	2.25; p = 0.13	11.13; p < 0.001	1.3; p = 0.25	20.0; p < 0.001	0.5; p = 0.48	0.5; p = 0.48

Displays the number of individuals classified as impaired at follow-up via practice effect-unadjusted scores and -adjusted scores. The “Stable M MCI” column provides the count of participants who met criteria for multiple domain mild cognitive impairment (M MCI) at baseline and at follow-up. The “Stable S MCI” provides the same information about individuals with single domain MCI (S MCI). Individuals who progressed from S MCI at baseline to M MCI at follow-up are displayed in the “Progression” column. The “Stable Impairment” section describes the number of individuals who retained an impairment in a specific cognitive domain at follow-up, regardless of whether they met criteria for an impairment in another domain at either visit. The Difference row displays how many more participants meet criteria for that classification or impairment when adjusting for practice effects (i.e., Adjusted count – Unadjusted count). The percent listed in this row displays the percent increase in stability when accounting for practice effects: difference/Unadjusted count. McNemar χ² tests were used to evaluate the impact of practice-effect adjustment on classification or impairment stability; p-values are presented.