LAUSR

Sleep spindles are neural oscillations of frequency between 11 to 16 Hz during non rapid eye movement sleep. They are coordinated with hippocampal ripples and slow oscillations to facilitate memory consolidation by modulating synaptic plasticity. Fast spindles, predominant in central and parietal derivations of EEG during Stage 2 NREM sleep, are associated with overnight visuomotor skills enhancement, especially in the later part of the night. The relationship between fast and slow spindles during sleep and psychomotor ability has not been characterized well, particularly in older adults. The objective of this study was to study the relationship between sleep microstructure during various stages of sleep and cognition in good and poor sleepers. This is a cross sectional observational study conducted on 16 male participants (age 63.6 ± 5.22 years). Good (n=9) and poor sleepers (n=7) were classified on the basis of PSQI score (<=5 is good). Overnight polysomnography was done and ICMR-NCTB battery was administered for assessment of cognition. In DOMINO software, after visual artifact removal, spindles were analyzed by selecting 11 - 12.99 Hz (slow) in F4, and 13 -16 Hz (fast) in C2. Statistical analysis was done using GraphPad prism (v 9.4.1). Fast spindle index in N2 (good sleeper: r = -0.850, p = 0.006; poor sleeper: r = 0.398, p = 0.466), fast spindle density in N2 (good sleeper: r = -0.870, p = 0.004; poor sleeper: r = -0.331, p = 0.468), total fast spindle number during deep sleep (good sleeper: r = -0.600, p = 0.031; poor sleeper: r = -0.244, p = 0.599), and total slow spindle density (good sleeper: r = -0.833, p = 0.025; poor sleeper: r = -0.080, p = 0.865) were found to be negatively correlated with psychomotor ability assessed by trail making test. Among older adults, good sleepers, as compared to poor sleepers overall have a higher fast spindle index and density during N2 sleep and there is significant correlation with better psychomotor ability. All India Institute of Medical Sciences and University College of London Collaborative Grant (AIIMS-UCL 12)