High Frequency Stimulation to Improve Cognition, Mobility, and Affect in Individuals With and Without Subjective Cognitive Decline

Inclusion Criteria: * Community dwelling men and women 65-89 years old * Ability to walk unassisted for 10 min * English speaking Additional Inclusion Criteria for SCD: * No evidence of dementia or MCI based on cognitive screening (i.e., Montreal Cognitive Assessment (MoCA) score within normal limits for age, education, and sex using the NACC Uniform Data Set (UDS) norms8 * Global Clinic Dementia Rating (CDR) score must be 0 or 0.531 * Subjective report of cognitive complaints with scores \>20 on the Cognitive Change Index (CCI-20), a validated scale of subjective cognitive decline6; this scale consists of 20 items that are rated on a 5-point Likert scale, where 1= "Normal: No change compared to 5 years ago", 3= "Mild Problem: Some change compared to 5 years ago) and 5="Severe Problem: Much worse compared to 5 years ago" * Family history of dementia/probable AD in first degree relative (parents, children, siblings) * Normal functional behavior in terms of daily activities, based on the Functional Activities Scale32 * In line with recommendations of the SCD task force33 an informant must be available for two reasons: a) to provide information about the participant's cognition using the informant version of the CDR and CCI-20, and b) to corroborate normal IADL's on the Functional Activity Questionnaire32 (informant data will be collected via a phone call and linked by code with the participant data). Exclusion Criteria: * If participants score less than 21 on the Telephone…