Modulating Brain Activity to Improve Goal-directed Physical Activity in Older Adults

Study Overview
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Brief Summary
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Although the majority of older adults are aware of the compelling evidence that regular exercise is critical to the maintenance of health into old age, most do not meet recommendations for daily exercise. This lack of engagement in 'goal-directed' physical activity stems from numerous interrelated factors including lack of motivation, depressed mood, and cognitive executive impairments that diminish one's ability to regulate behavior over time. Intriguingly, each of these factors has been linked to the function of brain networks that include the left dorsolateral prefrontal cortex (dlPFC). Transcranial direct current stimulation (tDCS) is a noninvasive and safe means of modulating the excitability of specific brain regions and their connected neural networks. tDCS designed to facilitate the excitability of the left dlPFC has been shown to improve motivation, mood, and multiple aspects of executive function in healthy adults. The investigators thus hypothesize that tDCS holds promise to increase goal-directed physical activity in older adults. This project aims to conduct a pilot randomized controlled trial on the feasibility and effects of a 2-week, 10-session tDCS intervention targeting the left dlPFC, combined with behavioral intervention aimed at increases daily physical activity, on physical activity over a two-month follow-up period, in relatively sedentary older adults without overt illness or disease.

Official Title
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Modulating Brain Activity to Improve Goal-directed Physical Activity in Older Adult

Conditions
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Aging

Intervention / Treatment
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* Device: Transcranial direct current stimulation (tDCS)
* Device: Sham stimulation
* Behavioral: Behavioral intervention to increase physical activity


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Must live within subsidized housing in the Boston area Self-report of exercising, on average, less than 150 minutes of at least moderate-intensity exercise per week, as determined by phone-screen completion of the International Physical Activity Questionnaire-Short Form (IPAQ short) Exclusion Criteria: An inability to ambulate without the assistance of another person (canes or walkers allowed) Self-report of physician-diagnosed dementia, more than moderate cognitive impairment defined as a Montreal Cognitive Assessment (MoCA) score <21, or an inability to understand the study protocol as determined by study staff A clinical history of stroke, Parkinson's disease or parkinsonian syndromes, multiple sclerosis, normal pressure hydrocephalus or other movement disorder affecting gait Any report of severe lower-extremity arthritis or physician-diagnosis of peripheral neuropathy Use of antipsychotics, anti-seizure, benzodiazepines, or other neuroactive medications Severe depression defined by a Geriatric Depression Scale score greater than 11 Any report or physician-diagnosis of schizophrenia, bipolar disorder or other psychiatric illness Any unstable medical condition Resting systolic blood pressure is higher than 180 mmHg Contraindications tor tDCS, including reported seizure within the past two years, use of neuro-active drugs, self-reported presence of specific implanted medical devices (e.g., deep brain stimulator, medication infusion pump, cochlear implant, pacemaker, etc.), or the presence of any active dermatological condition, such as eczema, on the scalp

Ages Eligible for Study
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Minimum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Behavioral intervention plus tDCS<br>This intervention will consist of a two-month, personalized, goal-based counseling approach to promote physical activity. Over the first two weeks of the behavioral intervention, participants will also received 10, once-daily, 20-minute sessions of transcranial direct current stimulation (tDCS) designed to increase the excitability of the left dorsolateral prefrontal cortex. | Device: Transcranial direct current stimulation (tDCS)<br>* tDCS will be delivered via six gel electrodes with placement and current parameters optimized based on a standard brain to maximize the average normal component of the generated electric field over the left dlPFC. Current delivered by anyone electrode will never exceed 2.0 mA; the total amount of current from all electrodes will not exceed 4 mA. Each 20-minute session will begin and end with a 60-second ramp up/down of current amplitude to maximize comfort.<br>Behavioral: Behavioral intervention to increase physical activity<br>* Study staff will complete face-to-face and telephone counseling sessions with each participant, tailored to their state of readiness to increase physical activity levels. The participant will be provided with a goal to increase their average daily step count by 20% from baseline. The staff member will review the participant's stated barriers to exercise and provide them with a list of strategies they may use to augment their step counts throughout each day. Bi-weekly face-to-face counseling sessions will then be completed to review and discuss activity performance and answer any questions the participant may have regarding their efforts to increase physical activity.<br>|
| Active Comparator: Behavioral intervention plus sham stimulation<br>This intervention will consist of a two-month, personalized, goal-based counseling approach to promote physical activity. Over the first two weeks of the behavioral intervention, participants will also received 10, once-daily, 20-minute sessions of sham stimulation. | Device: Sham stimulation<br>* An 'active' sham will be used in which very low-level currents are transferred between the same electrodes used in the active condition throughout the 20-minute session. However, currents will be designed to mimic the cutaneous sensations induced by tDCS yet not significantly influence cortical tissue.<br>Behavioral: Behavioral intervention to increase physical activity<br>* Study staff will complete face-to-face and telephone counseling sessions with each participant, tailored to their state of readiness to increase physical activity levels. The participant will be provided with a goal to increase their average daily step count by 20% from baseline. The staff member will review the participant's stated barriers to exercise and provide them with a list of strategies they may use to augment their step counts throughout each day. Bi-weekly face-to-face counseling sessions will then be completed to review and discuss activity performance and answer any questions the participant may have regarding their efforts to increase physical activity.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Daily step count | Number of steps per day | Average over a two-week baseline; Average over six weeks following the two-week tDCS intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gait speed | Average speed of walking during 60 seconds of continuous walking at preferred speed | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention | 
| Timed Up-and-Go (TUG) | A common field test of mobility | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention | 
| Digit Span | A neuropsychological test of working memory | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention | 
| Trail Making Test (TMT) | A neuropsychological test of executive function | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention | 
| Montreal Cognitive Assessment (MoCA) total score | Global cognitive function. The range for this test is 0-30, with higher score representing better outcome. | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention | 
| Geriatric Depression Scale (15-item) | Number of depressive symptoms. The range for this test is 0-15, with lower score representing better outcome. | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention | 
| Self-efficacy scale for walking (SES-W) | Self-efficacy for engaging in regular walking activity. The range for the test is 0-100, with higher score representing better outcome. | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention | 
| Moderate-to-vigorous physical activity | Number of minutes spent engaging in moderate-to-vigorous exercise per day | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention | 
| Sedentary behavior | Number of minutes spent sedentary per day | Baseline; 2 weeks following tDCS intervention; 8 weeks following tDCS intervention |