Cognitive Function and Insomnia Symptoms are Associated With Subjective-Objective Sleep Discrepancies in Older Adults Without Dementia

Background Accurate sleep assessment is key to promoting healthy aging, yet self-reported measures often diverge from actigraphy. The factors driving these discrepancies in older adults remain unclear. Methods This cross-sectional secondary analysis examined the prevalence and correlates of subjective-objective sleep discrepancies in 195 community-dwelling older adults (69.84 ± 6.83 years old, 78.97% women) without dementia using baseline data from two clinical trials. Time in bed (TIB), sleep onset latency (SOL), total sleep time (TST), and sleep efficiency were collected via ≥3 days of actigraphy, sleep diaries, and the Pittsburgh Sleep Quality Index (PSQI). Discrepancies were calculated as self-reported minus actigraphy values, using ±15 min (±15% for sleep efficiency) as thresholds. Validated scales assessed insomnia, sleepiness, pain, and depression. Computerized batteries assessed processing speed, attention, executive function, working memory, and episodic memory. Results Discrepancies greater than ±15 min (or ±15%) were prevalent: 88.50% for TST, 81.25% for TIB (PSQI), 45.71% for TIB (diary), 45.87% for SOL, and 42.20% for sleep efficiency. Adjusted multinomial logistic regression revealed that more severe insomnia symptoms were significantly associated with reduced odds of over-reporting sleep efficiency on the PSQI (OR = 0.82, 95% CI 0.72, 0.94). Although no longer significant after correcting for multiple comparisons, better verbal episodic memory was associated with greater odds of over-reporting sleep efficiency (OR = 2.11, 95% CI 1.10, 4.07) and lower odds of under-reporting diary-based TIB (OR = 0.32, 95% CI 0.13, 0.76). Conclusion Cognitive function and insomnia are linked to sleep discrepancies and may affect perceived sleep quality, warranting careful interpretation of self-reported sleep in older adults.