Feasibility and safety of sequential transcranial direct current stimulation (tDCS) and physical therapy (PT) in older adults at risk of falling: A randomized pilot feasibility study

To establish the feasibility and safety of administering transcranial direct current stimulation (tDCS) immediately prior to physical therapy (PT) sessions in older adults at risk of falls. A pilot randomized controlled study. Outpatient geriatric physical therapy clinic. Ten older adults living within supportive housing facilities (86.8±7.9 y/o, 8F) were enrolled in the study. Participants received tDCS or sham stimulation targeting the left dorsal lateral prefrontal cortex (dlPFC) for 20 minutes, immediately prior to up to ten of their PT visits. Feasibility, safety, and functional outcomes were reported to inform the design of a larger and more definitive trial. Six fallers (88.8±5.0 y/o, 5F) completed the study and received 82.3% of the possible stimulation sessions, suggesting adding a 20-minute session of stimulation immediately prior to physical therapy training sessions, along with pre- and pos- assessments is feasible. The blinding strategy was successful and all reported side effects were expected and transient. While feasible and safe, the trial was met with numerous challenges, including selection bias, time and energy commitment, and large variation in functional performance, that must be considered when designing and implementing larger more definitive trials. This study provides preliminary evidence about the feasibility, safety, and challenges to combine PT and tDCS in very frail older adults.