EVALUATING THE COGNITIVE EFFECTS OF EXERCISE PRIMING AND TRANSCRANIAL DIRECT CURRENT STIMULATION IN MILD COGNITIVE IMPAIRMENT AND MILD ALZHEIMER'S DISEASE: THE EXPRESS STUDY

Abstract

Introduction Current pharmacotherapies for Alzheimer's disease (AD) are only modestly effective. There remains a critical need for treatments focused on early stages of the disease, when quality of life is still potentially excellent. While transcranial direct current stimulation (tDCS) has been shown to improve memory in some people with Mild Cognitive Impairment (MCI) and mild AD with minimal side-effects, recent evidence suggests that tDCS works better when brain circuits are active. As exercise increases brain activity using mechanisms that may support tDCS response, it may be an effective primer given before tDCS. This study assesses whether exercise priming with tDCS can help improve memory in MCI and mild AD, and whether this combination improves memory better than exercise or tDCS alone. Methods In this 5-week, randomized, blinded, sham-controlled clinical trial, eligible patients receive either 1) combined exercise and tDCS, 2) exercise and sham tDCS, or 3) exercise education only and tDCS. Repeated measures analyses of covariance will be conducted to evaluate between-group differences on cognitive outcomes over time. Results Blinded preliminary findings are presented (N=10, mean age=74±6?years, 50% female, mean years of education=16.2±2.5?years, mean Montreal Cognitive Assessment (MoCA) score= 21.5±2.9). There was a significant effect of treatment over time on Word Recall scores (F(2,7)=5.5, p=0.036). There were no statistically significant differences between groups over times on MoCA (F(2,7)=3.6, p=0.085) or Word Recognition scores (F(2,7)=4.5, p=0.054). Participants randomized to exercise education only with tDCS did not increase their exercise frequency or intensity according to the Leisure Time Exercise Questionnaire. Participants randomized to exercise priming were able to exercise at a moderate-intensity level for the last two weeks of the study when receiving combined tDCS or sham tDCS treatment. Overall adherence to study interventions was 98%. Conclusions Recruitment is ongoing (N=10/30). Updated results will be presented. This study may identify a new, feasible, non-invasive combination therapy that improves cognitive function in MCI and early stages of AD, therefore having major health implications. This research was funded by: Canadian Institutes of Health Research