Commentary on “Group-Based Exercise Combined with Dual-Task Training Improves Gait but not Vascular Health in Active Older Adults without Dementia” - Missed Opportunities for Mediation Analyses

Abstract

OMICS International Commentary AbstractThis commentary considers the implications of the findings related to the effect of a community-based, multiple modality and dual-task exercise training program in the Archives of Gerontology and Geriatrics. Findings from this study suggest that participants who performed the multiple modality and dual-task exercise intervention experienced greater improvements in global cognition, greater elevations in dual-task gait speed and dual-task step-length and greater reductions in dual-task stride time variability when compared to participants who did not perform the dual-task component of the exercise training program. The ability of exercise to impart cognitive and other physiological benefits has been long understood; however, the mechanisms that facilitate these training-induced improvements remain elusive. Mediation analyses provide a unique avenue to investigate the relationship between various physiological measures and can provide insight related to the causal sequence that drives the beneficial physiological and psychological response to an intervention. Recent works have incorporated mediation analyses within their study designs and the insight provided therein has revealed a number of intriguing intricacies with respect to cognition in aging and the effect of exercise on the body and brain. Mediation analyses are rarely utilized in neurophysiological research; however, the complex phenomenological relationships that can be revealed using this method will be crucially required for the identification of factors responsible for improvements in cognition following pharmacological or lifestyle-based interventions, and the development of effective management strategies for older adults with cognitive impairment. This commentary considers the implications of the findings related to the effect of a community-based, multiple modality and dual-task exercise training program previously described by Gregory et al. [1] in the Archives of Gerontology and Geriatrics. The authors report that participants who performed the multiple modality and dual-task exercise intervention experienced greater elevations in dual-task gait speed and dual-task step-length and reductions in dual-task stride time variability when compared to participants who did not perform the dualtask component of the exercise training program. These results were secondary to the primary analysis concerning change in cognition postexercise training [2], which suggested that participants performing the multiple modality and dual-task exercise training program experienced greater elevations in global cognitive functioning when compared to those who performed the multiple modality exercise program alone; these improvements were driven by improvements in verbal learning and memory and verbal fluency scores. Commentary on "Group-BasedAlthough this study was a well-designed randomized controlled trial (RCT) that collected a number of physiological, psychological and behavioural outcomes, the primary limitation to the interpr...