Could a caregiver-given brain zap at home prevent falls in seniors?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Inclusion criteria will be the same for PF/PA pairs in both Phase 1 and Phase 2 of the study. All participant pairs who complete either Phase 1 or 2 will be eligible to complete Phase 3. All participant teams who complete Phase 3 in its entirety will be eligible to complete Phase 4 PF group: * Aged 60+ * Self-report of one or more falls within the past year, and/or concern of falling in the future, and/or self-report of Parkinson's disease. * Able to read, write, and communicate in English * Able to identify an eligible PA to participate with them in the study PA group: * At least 21 years of age * Able to read, write, and communicate in English * Self-reported computer proficiency and willingness to learn how to use tDCS * Stated availability during weekdays throughout the study period to administer tDCS to the PF Exclusion Criteria: * Exclusion criteria will be the same for PF/PA pairs in both Phase 1 and Phase 2 of the study. PF group: * Evidence of cognitive impairment that would likely interfere with one's ability to understand the study protocol, risks/benefits, and testing procedures. This will be defined as self-reported diagnosis of Alzheimer's disease or dementia, a score of ≤19 on the Telephone Interview for Cognitive Status (TICS) at the time of telephone screening, a score of 18 or less on the Montreal Cognitive Assessment (MoCA) during the in-person screen, or an inability to understand study procedures following review of the Informed Consent form. * Inability to stand or ambulate unassisted for at least 25 feet. * Contraindications to tDCS, including a reported seizure within the past two years, use of neuro-active drugs, the risk of metal objects in the brain, skull, or head, self-reported presence of specific implanted medical devices (e.g., deep brain stimulator, medication infusion pump, cochlear implant), or the presence of any active, uncontrolled dermatological condition, such as eczema, on the scalp. PA group: * Mild cognitive impairment defined by a TICS score ≤34 during the phone screen, a MoCA score ≤24 during the in-person screen, or insufficient understanding of study procedures following review of the Informed Consent form. * Poor eyesight, severe arthritis in the hands, pain, deformity or other condition that interferes with successful administration of tDCS.