Cognitive Function and Functional Mobility Predict Exercise Adherence in Older Adults Who Fall

Introduction: Strength and balance exercises prevent falls. Yet, exercise adherence is often low. To maximize the benefit of exercise on falls prevention, we aimed to identify baseline cognitive and mobility factors that predict adherence to the Otago Exercise Program (OEP) - a home-based exercise program proven to prevent falls. Methods: We conducted a secondary longitudinal analysis of data from a randomized clinical trial (RCT) (OEP compared with usual care) among 172 participants who were assigned to the OEP intervention of the RCT. Adherence to the OEP was calculated as a percent score (i.e., [frequency of strength and balance retraining session per week/3 strength and balance retraining sessions per week] × 100). Executive function (i.e., mental flexibility) was measured using the Trail Making Tests (Part A and B: TMT B - TMT A) and the Digit Symbol Substitution Test (DSST). Short-term memory and encoding was measured using the Verbal Digits Forward test. Executive function (i.e., inhibition and working memory) was measured using the Stroop Color-Word Test and the Verbal Digits Forward minus Verbal Digits Backward test. Mobility was assessed using the Short Performance Physical Battery and the Timed Up and Go test. We used general estimation equations analysis to determine the predictors of adherence to the OEP. Results: Better set shifting (β = -0.06, z = -2.43, [SE = 0.02] p = 0.018] predicted greater OEP adherence. Greater attention and short-term memory (β = -6.99, z = -2.37 [SE = 2.95]) predicted poorer OEP adherence. Response inhibition, processing speed, working memory, and mobility assessed by the SPPB were not associated with adherence. Poorer baseline Timed Up and Go (β = 1.48 z = 1.94, [SE = 0.76]; p < 0.001), predicted better OEP adherence. Conclusion: Specific cognitive processes (i.e., executive function of set shifting, attention, and short-term memory) and functional mobility predicted exercise adherence. Further research needs to explore the pathways that explain why better attention and short-term memory predicted lower adherence and why poorer functional mobility led to better OEP adherence.