tDCS in Elderly Fallers Study

The objective of this study is to determine if a four-week, 20-session intervention of transcranial direct current stimulation (tDCS), as compared to sham intervention, improves dual task standing and walking performance (Aim 1), as well as other physical (Aim 2) and cognitive (Aim 3) factors on the causal pathway to falls, in older adults who report two or more falls within the past year and fear of falling again in the future, yet who do not have any acute or over neurological or musculoskeletal condition. Primary endpoints will include the "dual task" costs to gait speed when walking and postural sway speed when standing, as induced by performing a serial subtraction cognitive task (i.e., \[(speeddual task - speedsingle task) / speedsingle task) X 100\] (Aim 1), the Short Physical Performance Battery (Aim 2), and the Trail Making Test (Part B minus Part A) (AIM 3). Secondary endpoints will include the dual task cost to serial subtraction performance, additional gait and balance outcomes derived from the dual task paradigm, the Timed Up-and-Go, fear of falling, habitual physical activity, and performance within a battery of neuropsychological tests focused on global cognitive function, attention, verbal fluency and memory.

Inclusion Criteria: * Men and women aged 60 or older * Self-report of mobility and balance problems * Self-report of fear of falling defined by a "yes" answer to the yes-or-no question "Is the participant worried about falling in the future?" * Trail Making Test (TMT) Part B time below 75th percentile of age-and education-based norms * A score of 10 or below on the Short Physical Performance Battery Exclusion Criteria: * Inability to stand or walk unassisted for 60 seconds * Hospitalization within the past three months due to acute illness, or as the result of a musculoskeletal injury significantly affecting gait or balance * Any unstable medical condition * a diagnosis of a gait disorder, Parkinson's disease, Alzheimer's disease or dementia, multiple sclerosis, previous stroke or other neurodegenerative disorder * Chronic vertigo * Myocardial infarction within the past 6 months * Active cancer for which chemo-/radiation therapy is being received * Psychiatric co-morbidity including major depressive disorder, schizophrenia or psychosis * Chronic use of any sedating medications (sedatives, anti-psychotics, hypnotics, anti-depressants) or change in medication within the previous month * Legal blindness * Contraindications to MRI or tDCS, including reported seizure within the past two years, use of neuro-active drugs, the risk of metal objects anywhere in the body, 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 * A score below 22 on the Telephone Interview of Cognitive Status (TICS) * Mild or severe dementia defined by a Clinical Dementia Rating (CDR) score of one or greater