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

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

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.

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