0122 Does Additional Training on an Implicit Motor Sequence Learning Task for Older Adults Improve Sleep-Dependent Memory Consolidation?

Abstract

Abstract Introduction Previous studies show sleep dependent consolidation (SDC) for motor sequence learning with regular training in younger adults, whereas, in older adults, this sleep benefit is missing. If hippocampal engagement underlies age-related differences in SDC, then enhanced training should result in significant SDC in older adults. Thus, this study aims to look at younger vs. older adults with regular training and older adults with regular training vs. overtraining to determine if older adults show evidence of SDC. Alternatively, regardless of initial learning, older adults may fail to exhibit SDC because the sleep mechanisms supporting consolidation are impaired. Methods Seven younger adults (M=22 years) and seven older adults (M=68.5 years) completed the train condition, while ten older adults (M=67.6 years) completed the overtrain condition. In the encoding phase, participants either completed 5 blocks (train) or 10 blocks (overtrain). Between immediate and delayed recall, participants either slept with Polysomnography (PSG) in the lab or remained awake, and subsequently, completed the alternate condition one week later. Actigraphy was collected for 14 days and PSG (32-electrode EasyCap) was recorded for overnight sleep. Results Older adults significantly improved their skill learning from immediate to delayed recall, in both the train (p=0.005) and overtrain (p=0.013) conditions, regardless of sleep or wake. Younger adults did not improve their skill learning in the train condition (p>0.05). However, there was a trending main effect, with younger adults performing the task better compared to older adults in the train condition, at both time points (p=0.061). No other main effects or interactions were significant. Conclusion These results suggest the alternative hypothesis that, regardless of initial learning, older adults fail to exhibit SDC. This result is of interest as the age-related differences in sleep, such as sleep spindle characteristics may play a role. Future analysis will include more participants and further exploration into the PSG-recorded sleep architecture and actigraphy-recorded measures of habitual sleep. Support This work was funded by NIH R01 AG040133 (PI: Spencer)