Association of Poor Sleep Efficiency With Decreased Executive Function and Impaired Episodic Memory in Older Adults

Sleep characteristics influence both physical and psychological health. While previous studies have reported links between sleep quality and cognitive impairment in older adults, findings remain inconsistent, and evidence from the Indian population using culturally validated cognitive tools is scarce.

This study aims to examine the relationship between subjective sleep quality and cognitive performance in Indian older adults using the Pittsburgh Sleep Quality Index (PSQI) and the Indian Council of Medical Research-Neurocognitive Toolbox (ICMR-NCTB).

In this cross-sectional study, 67 individuals aged 50-80 years completed the PSQI and the Hindi version of the ICMR-NCTB. Participants were categorized as good (PSQI ≤ 5) or poor (PSQI > 5) sleepers. Cognitive domains assessed included global cognition, language, attention, visuospatial ability, executive function, and episodic memory. Group comparisons and correlation analyses were performed to explore associations between sleep quality and cognitive outcomes.

Sleep latency and sleep efficiency were significantly associated with cognitive performance. Longer sleep latency correlated with poorer executive function (Trail Making Test (TMT)-B: r = 0.347, p = 0.006; TMT-(B-A): r = 0.289, p = 0.023) and reduced performance in verbal learning (Verbal Learning Test (VLT) delayed recall: r = -0.183, p = 0.141; delayed recognition: r = -0.284, p = 0.02). Higher sleep efficiency was linked to better executive function and episodic memory. Poor sleepers scored significantly lower on global cognition (Montreal Cognitive Assessment (MoCA), p = 0.047), executive function (TMT-B, p = 0.029), verbal fluency (Phonemic Fluency Task (PFT), p = 0.031), and delayed recall (VLT, p = 0.045) compared to good sleepers. Education was positively associated with most cognitive scores but not with sleep quality.

Prolonged sleep latency and poor sleep efficiency were associated with deficits in executive function and memory among older adults. These findings underscore the importance of sleep quality in cognitive aging, and the use of a culturally adapted cognitive tool enhances their applicability in low-literacy, non-Western settings.