The Potential of Transcranial Alternating Current Stimulation to Alleviate Dual-Task Gait Costs in Older Adults: Insights from a Double-Blinded Pilot Study

• Published in: Gerontology (Basel) Vol. 69; no. 4; pp. 513 - 518
• Main Authors: Sayig-Keren, Rony M., Dagan, Moria, Cornejo Thumm, Pablo, Brozgol, Marina, Gazit, Eran, Manor, Brad, Hausdorff, Jeffrey M.
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland 01.04.2023
• Subjects: Aged; Cross-Over Studies; Gait - physiology; Humans; Pilot Projects; Technological Section: Brief Report; Transcranial Direct Current Stimulation - methods; Cognitive; Noninvasive brain stimulation; Gait; Dual task
• ISSN: 0304-324X; 1423-0003
• DOI: 10.1159/000527171

Abstract Background: The performance of an attention-demanding task while walking, i.e., dual-tasking, leads to dual-task costs (e.g., reduced gait speed) in older adults. Previous studies have shown that dual-task costs in gait are associated with future falls and cognitive decline. According to the communication through coherence hypothesis, transcranial alternating current stimulation (tACS) might help alleviate this problem. Objective: The aim of this study was to examine the effects of a single session of theta-tACS targeting the left fronto-parietal network (L-FPN) on dual-task walking and cognitive function compared to sham stimulation and transcranial direct current stimulation (tDCS) targeting the left dorsolateral prefrontal cortex, a node within the L-FPN. Methods: Twenty older adults completed a four-visit, double-blinded, within-subject, cross-over study in which usual-walking, dual-task walking, and cognitive function were evaluated before and immediately after 20 min of tACS, tDCS, or sham (order randomized) stimulation. Dual-task costs to gait speed (primary outcome) and other measures were analyzed. Results: The dual-task cost to gait speed tended to be lower (i.e., better) after tACS (p = 0.067, Cohen’s d = 0.433∼small); tDCS significantly reduced this dual-task cost (p = 0.012, Cohen’s d = 0.618∼medium), and sham stimulation had no effect (p = 0.467). tACS significantly reduced the dual-task cost to step length (p = 0.037, Cohen’s d = 0.502∼medium); a trend was seen after tDCS (p = 0.069, Cohen’s d = 0.443∼small). No statistical differences were found for other measures of gait or cognitive function. Conclusions: The positive effects of tACS on dual-task gait speed and step length were roughly similar to those seen with tDCS. These results suggest that tACS affects the fronto-parietal network and, similar to tDCS, tACS may improve dual-tasking. Nonetheless, to achieve larger benefits and differentiate the effects of tACS and tDCS on brain function and dual-task walking in older adults, other stimulation montages and protocols should be tested.