Transcranial Direct Current Stimulation May Improve Cognitive-Motor Function in Functionally Limited Older Adults

• Published in: Neurorehabilitation and neural repair 2018-09, Vol.32 (9), p.788-798
• Main Authors: Manor, Brad, Zhou, Junhong, Harrison, Rachel, Lo, On-Yee, Travison, Thomas G., Hausdorff, Jeffrey M., Pascual-Leone, Alvaro, Lipsitz, Lewis
• Format: Article
• Language: English
• Subjects: Aged; Cognition - physiology; Double-Blind Method; Executive Function - physiology; Female; Humans; Male; Motor Skills - physiology; Neuropsychological Tests; Transcranial Direct Current Stimulation; Treatment Outcome; Walking - physiology
• ISSN: 1545-9683; 1552-6844; 1552-6844
• DOI: 10.1177/1545968318792616

Objective. To determine the effects of a transcranial direct current stimulation (tDCS) intervention with the anode placed over the left dorsolateral prefrontal cortex (dlPFC) and cathode over the right supraorbital region, on cognition, mobility, and “dual-task” standing and walking in older adults with mild-to-moderate motor and cognitive impairments. Methods. A double-blinded, block-randomized, sham-controlled trial was conducted in 18 nondemented, ambulatory adults aged ⩾65 years with slow walking speed (⩽1.0 m/s) and “executive” dysfunction (Trail Making Test B score ⩽25th percentile of age- and education-matched norms). Interventions included ten 20-minute sessions of tDCS or sham stimulation. Cognition, mobility, and dual-task standing and walking were assessed at baseline, postintervention, and 2 weeks thereafter. Dual tasking was also assessed immediately before and after the first tDCS session. Results. Intervention compliance was high (mean ± SD = 9.5 ± 1.1 sessions) and no unexpected or serious side effects were reported. tDCS, compared with sham, induced improvements in the Montreal Cognitive Assessment total score (P = .03) and specifically within the executive function subscore of this test (P = .002), and in several metrics of dual-task standing and walking (P < .05). Each of these effects persisted for 2 weeks. tDCS had no effect on the Timed Up-and-Go test of mobility or the Geriatric Depression Scale. Those participants who exhibited larger improvements in dual-task standing posture following the first tDCS session exhibited larger cognitive-motor improvements following 2 weeks of tDCS (P < .04). Interpretation. tDCS intervention designed to stimulate the left dorsolateral prefrontal cortex may improve executive function and dual tasking in older adults with functional limitations.