Long-term effects of cognitive training on everyday functional outcomes in older adults

Abstract

Context: Cognitive training has been shown to improve cognitive abilities in older adults but the effects of cognitive training on everyday function have not been demonstrated.

Objective: To determine the effects of cognitive training on daily function and durability of training on cognitive abilities.

Design, setting, and participants: Five-year follow-up of a randomized controlled single-blind trial with 4 treatment groups. A volunteer sample of 2832 persons (mean age, 73.6 years; 26% black), living independently in 6 US cities, was recruited from senior housing, community centers, and hospitals and clinics. The study was conducted between April 1998 and December 2004. Five-year follow-up was completed in 67% of the sample.

Interventions: Ten-session training for memory (verbal episodic memory), reasoning (inductive reasoning), or speed of processing (visual search and identification); 4-session booster training at 11 and 35 months after training in a random sample of those who completed training.

Main outcome measures: Self-reported and performance-based measures of daily function and cognitive abilities.

Results: The reasoning group reported significantly less difficulty in the instrumental activities of daily living (IADL) than the control group (effect size, 0.29; 99% confidence interval [CI], 0.03-0.55). Neither speed of processing training (effect size, 0.26; 99% CI, -0.002 to 0.51) nor memory training (effect size, 0.20; 99% CI, -0.06 to 0.46) had a significant effect on IADL. The booster training for the speed of processing group, but not for the other 2 groups, showed a significant effect on the performance-based functional measure of everyday speed of processing (effect size, 0.30; 99% CI, 0.08-0.52). No booster effects were seen for any of the groups for everyday problem-solving or self-reported difficulty in IADL. Each intervention maintained effects on its specific targeted cognitive ability through 5 years (memory: effect size, 0.23 [99% CI, 0.11-0.35]; reasoning: effect size, 0.26 [99% CI, 0.17-0.35]; speed of processing: effect size, 0.76 [99% CI, 0.62-0.90]). Booster training produced additional improvement with the reasoning intervention for reasoning performance (effect size, 0.28; 99% CI, 0.12-0.43) and the speed of processing intervention for speed of processing performance (effect size, 0.85; 99% CI, 0.61-1.09).

Conclusions: Reasoning training resulted in less functional decline in self-reported IADL. Compared with the control group, cognitive training resulted in improved cognitive abilities specific to the abilities trained that continued 5 years after the initiation of the intervention.

Trial registration: clinicaltrials.gov Identifier: NCT00298558.

Figure 1

Conceptual Model of ACTIVE Trial ACTIVE indicates Advanced Cognitive Training for Independent and Vital Elderly; ADL, activities of daily living; IADL, instrumental activities of daily living.

Figure 2

Flow of Individuals in ACTIVE Trial ACTIVE indicates Advanced Cognitive Training for Independent and Vital Elderly. *Site-level decision was made to withdraw individual from the study.

Figure 3

Training Effects on Everyday Function by Self-reported Instrumental Activities of Daily Living (IADL) Difficulty Scores The mean scores are Blom-transformed. Error bars indicate SE. The sample sizes for each time point represent the number of cases with complete data for the IADL difficulty score.