Investigating the influence of paired-associative stimulation on multi-session skill acquisition and retention in older adults

Objective: Priming non-invasive brain stimulation (NIBS) can improve motor learning in the elderly, but it remains unclear how benefits observed in a single training session translate to multiple training sessions. The current study therefore examined the influence of priming NIBS on acquisition and retention of a novel motor skill over sequential training days in older adults. Methods: In 30 older adults (68.2 +/- 5.3 years, 14 females), paired-associative stimulation (PAS) was applied prior to visuomotor training on 3 consecutive days. The interstimulus interval used for PAS was either 10 ms (PAS(LTD)) or 100 ms (PAS(control)) and long-term retention was assessed by quantifying motor performance 7 days after the final training session. Results: During training, skill progressively increased across sessions (P < 0.0001), but this was not different between PAS(LTD) and PAS(control) (P > 0.1). In contrast, the magnitude of skill retained 7 days after training was significantly greater in the PAS(LTD) group (P = 0.02), suggesting significantly greater long-term retention of the trained skill. Conclusions: PAS(LTD) over multiple sessions may represent an effective tool to help maintain newly learned motor skills in older adults. Significance: While multisession priming with PAS can influence long-term skill retention, improving skill acquisition requires investigation of alternative protocols. (C) 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.