The Effects of Unilateral Upper Limb Motor Control Training on Cognitive Function in Older Adults

THE EFFECT OF UNILATERAL, LOW-INTENSITY, UPPER LIMB MOTOR CONTROL TRAINING ON COGNITIVE FUNCTION IN HEALTHY OLDER ADULTS:

A PILOT STUDY

Introduction
Age-related cognitive decline, particularly in executive function and processing speed, is a major concern. Physical exercise is recognised as a strategy to support cognitive health (1), however not all older adults are physically able to perform the ‘traditional’ forms of exercise (i.e., resistance and endurance exercise), which have been shown to elicit this benefit. Motor control training (MCT) is emerging as a potential alternative exercise modality, however, to date the effect of unilateral, upper-limb MCT on the cognitive abilities of older adults has not been investigated.

Methods
Twenty disease-free older adults aged ≥65 years (10 male, 10 female; 73.0 ± 2.1 years) completed a 4-week unilateral MCT programme by the self-determined dominant upper limb. MCT was performed three times each week, with assessments of cognition (Trail Making Test (TMT), Montreal Cognitive Assessment (MoCA), and Stroop Colour-Word Test (SCWT)) before and after the MCT, and 4 weeks after cessation of the MCT. IL-2 and brain-derived neurotrophic factor (BDNF) were also evaluated at these timepoints as potential biomarkers of cognition. Data was analysed via one-way ANOVA with significance accepted as p<0.05.

Results
TMT (28.49 ± 6.54 vs. 24.37 ± 7.83 sec; p = 0.01), MoCA (25.8 ± 1.82 vs. 28.2 ± 1.24 point; p < 0.0001), and SCWT interference scores (raw, p<0.0001)  significantly improved after MCT and remained improved at follow-up (TMT: 24.22±6.23 sec, p; MoCA: 28.6±1.31point, p=<0.0001; SCWT: 4.53 ± 7.43 vs.11.74 ± 9.90 point, p<0.0001).  In contrast, IL-2 and BDNF were not altered by MCT (p=0.21 and p=0.29, respectively), nor did they change in the post-MCT period (p=0.54 and p=0.65, respectively).

Conclusion

Unilateral, upper-limb MCT may provide cognitive benefits in older adults, including in executive function and attention. As these improvements were attainable in just 4 weeks, it may be applicable to clinical situations such as surgical prehabilitation. The lack of biomarker changes suggests that longer interventions may be needed to produce measurable neurobiological effects.

Reference:

1.            Erickson KI, Voss MW, Prakash RS, Basak C, Szabo A, Chaddock L, et al. Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences. 2011 Feb 15;108(7):3017–22.