Non-invasive Brain Stimulation to Improve Unsteady Gait in Older Adults (StimGait)

Inclusion Criteria: * Aged 65 and above. * Ability to speak and read English. * Ability to walk independently and continuously for at least 1 minute. * Elevated gait variability as defined by a coefficient of variation (CoV) about average stride time larger and equal to 0.025 during straight-line walking at preferred speed. Exclusion Criteria: * More than mild cognitive impairment defined by a Montreal Cognitive Assessment (MoCA) score less than 18. * Parkinson's disease, multiple sclerosis, stroke, active brain tumor, or other neurological disorders. * Self-reported pain or lower extremity deformity that significantly disrupts walking. * Contraindications to MRI or tDCS. * An episode of acute illness or exacerbation of a diagnosis that requires hospitalization or active treatment within the past 3 months. * Current treatment for congestive heart failure, angina, uncontrolled arrythmia, deep vein thrombosis, or other uncontrolled cardiovascular events. * Myocardial infarction, coronary artery bypass grafting, angioplasty, or other cardiac conditions within the past 3 months, * Active cancer for which chemo/radiation therapy is being received. * Psychiatric co-morbidity including major depressive disorder, schizophrenia, psychosis, or other psychiatric illness. * Recent use of any sedating medications (sedatives, anti-psychotics, hypnotics, anti-depressants) or change in medication within the previous month. * Chronic vertigo or other diagnosed vestibular disorders. * Legal…