Short-term practice effects in mild cognitive impairment: Evaluating different methods of change.

Practice effects are improvements on cognitive tests as a result of repeated exposure to testing material. However, variability exists in the literature about whether patients with amnestic mild cognitive impairment (MCI) display practice effects, which may be partially due to the methods used to calculate these changes on repeated tests. The purpose of the current study was to examine multiple methods of assessing short-term practice effects in 58 older adults with MCI. The cognitive battery, which included tests of memory (Hopkins Verbal Learning Test-Revised and Brief Visuospatial Memory Test-Revised) and processing speed (Symbol Digit Modalities Test and Trail Making Test Parts A and B), was administered twice across one week. Dependent t tests showed statistically significant improvement on memory scores (ps < .01, ds = 0.8-1.3), but not on processing speed scores. Despite this, the sample showed no clinically meaningful improvement on any cognitive scores using three different reliable change indices. Regression-based change scores did identify relatively large groups of participants who showed smaller than expected practice effects, which may indicate that this method is more sensitive in identifying individuals who may portend a declining trajectory. Practice effects remain a complex construct, worthy of continued investigation in diverse clinical conditions.