A Delayed Advantage: Multi-Session Training at Evening Hours Leads to Better Long-Term Retention of Motor Skill in the Elderly

Abstract

The acquisition and retention of motor skills is necessary for everyday functioning in the elderly and may be critical in the context of motor rehabilitation. Recent studies indicate that motor training closely followed by sleep may result in better engagement of procedural (“how to”) memory consolidation processes in the elderly. Nevertheless, elderly individuals are mostly morning oriented and a common practice is to time rehabilitation programs to morning hours. Here, we tested whether the time-of-day wherein training is afforded (morning, 8–10:30 a.m., or evening, 6–9 p.m.) affects the long-term outcome of a multi-session motor practice program (10 sessions across 3–4 weeks) in healthy elderly participants. Twenty-nine (15 women) older adults (60–75 years) practiced an explicitly instructed five-element key-press sequence by repeatedly generating the sequence “as fast and accurately as possible.” The groups did not differ in terms of sleep habits and quality (1-week long actigraphy); all were morning-oriented individuals. All participants gained robustly from the intervention, shortening sequence tapping duration and retaining the gains (> 90%) at 1-month post-intervention, irrespective of the time-of-day of training. However, retesting at 7-months post-intervention showed that the attrition of the training induced gains was more pronounced in the morning trained group compared to the evening group (76 and 56.5% loss in sequence tapping time; 7/14 and 3/14 participants showed a > 5% decline in accuracy relative to end of training, respectively). Altogether, the results show that morning-oriented older adults effectively acquired skill in the performance of a sequence of finger movements, in both morning and evening practice sessions. However, evening training leads to a significant advantage, over morning training, in the long-term retention of the skill. Evening training should be considered an appropriate time window for motor skill learning in older adults, even in individuals with morning chronotype. The results are in line with the notion that motor training preceding a sleep interval may be better consolidated into long-term memory in the elderly, and thus result in lower forgetting rates.

Better later: evening practice is advantageous for motor skill consolidation in the elderly

“…Moreover, significant qualitative changes occurred in the tapping pattern (vis à vis the pattern attained at the end of the session but also compared with the initial sequence tapping pattern) overnight in the Eve, but not in the Morn group; these qualitative changes were well maintained (and even enhanced) a week later. We conjecture that these differences in the offline reorganization of the movement routine may account for slower forgetting rates that were observed in the same Eve group participants at the 7-mo retest after the completion of the multisession training protocol ( Gal et al 2019 ). In order to gain insight into the nature of underlying processes and their effect on memories, changes in the tapping pattern should be considered together with changes in performance speed ( Gabitov et al 2017 ; Gabitov et al 2019a ).…”

“…In a recent study, following a multisession training on a finger tapping sequence task, we found that elderly participants who trained in the evening hours had significantly lower forgetting rates over a 6-mo period, than participants receiving morning training ( Gal et al 2019 ). That implies that evening training in the elderly may better engage (and sustain) memory consolidation processes and thus result in a more robust skill representation.…”

“…That implies that evening training in the elderly may better engage (and sustain) memory consolidation processes and thus result in a more robust skill representation. Here, we tested this hypothesis, in the same participants as in Gal et al (2019) , by analyzing changes in performance that occur overnight and 1 wk after the first session of evening or morning practice.…”

“…Detailed description of the methods has been published elsewhere ( Gal et al 2019 ). In short, differences in online (within session) and offline (posttraining) learning were assessed following practice on a given five-element sequence (4–1–3–2–4) in two groups of healthy morning-oriented participants (60–75 yr old, N = 14/group).…”

Effects of Sleep on Language and Motor Consolidation: Evidence of Domain General and Specific Mechanisms

“…Participants were trained to perform accurately and repeatedly a five-element sequence by tapping a 4-key response pad with their left (non-dominant) hand (Figure 3.a). This computerized version of the sequential finger tapping task, adapted from Karni, et al, (Karni, 1995;Karni et al, 1998), has been widely used to study mnemonic processes underlying learning of a new motor skill ( Albouy et al, 2015;Censor et al, 2010;Gabitov et al, 2019;Gal et al, 2019;King et al, 2017;Walker et al, 2002). For a recent review, see Doyon et al, (2018).…”