Longitudinal impact and effects of booster sessions in a cognitive training program for healthy older adults

This paper reports the results from a 3-year follow-up study to measure the long-term efficacy of a cognitive training for healthy older adults and investigates the effects of booster sessions using an entropy-based metric.

Design: semi-randomized quasi-experimental controlled design.

Participants: 50 older adults, (M = 73.3, SD = 7.77) assigned into experimental (N = 25; Mean age = 73.9; SD = 8.62) and control groups (N = 25; mean age = 72.9; SD = 6.97).

Instruments: six subtests of WAIS and two episodic memory tasks.

Procedures: the participants were assessed on four occasions: after the end of the original intervention, pre-booster sessions (three years after the original intervention), immediately after the booster sessions and three months after the booster sessions.

Results: the repeated measures ANOVA showed that two of the cognitive gains reported in the original intervention were also identified in the follow-up: Coding (F(1, 44) = 11.79, MSE = 0.77, p = .001, eta squared = 0.084) and Picture Completion (F(1, 47) = 10.01, MSE = 0.73, p = .003, eta squared = 0.060). After the booster sessions, all variables presented a significant interaction between group and time favorable to the experimental group (moderate to high effect sizes). To compare the level of cohesion of the cognitive variables between the groups, an entropy-based metric was used. The experimental group presented a lower level of cohesion on three of the four measurement occasions, suggesting a differential impact of the intervention with immediate and short-term effects, but without long-term effects.