Targeted tDCS Mitigates Dual‐Task Costs to Gait and Balance in Older Adults

Objective Among older adults, the ability to stand or walk while performing cognitive tasks (ie, dual‐tasking) requires coordinated activation of several brain networks. In this multicenter, double‐blinded, randomized, and sham‐controlled study, we examined the effects of modulating the excitability of the left dorsolateral prefrontal cortex (L‐DLPFC) and the primary sensorimotor cortex (SM1) on dual‐task performance “costs” to standing and walking. Methods Fifty‐seven older adults without overt illness or disease completed 4 separate study visits during which they received 20 minutes of transcranial direct current stimulation (tDCS) optimized to facilitate the excitability of the L‐DLPFC and SM1 simultaneously, or each region separately, or neither region (sham). Before and immediately after stimulation, participants completed a dual‐task paradigm in which they were asked to stand and walk with and without concurrent performance of a serial‐subtraction task. Results tDCS simultaneously targeting the L‐DLPFC and SM1, as well as tDCS targeting the L‐DLPFC alone, mitigated dual‐task costs to standing and walking to a greater extent than tDCS targeting SM1 alone or sham (p