SLEEP ARCHITECTURE CHANGES WITH THE DEGREE OF COGNITIVE DECLINE IN PEOPLE WITH DEMENTIA

Sleep plays a fundamental role in maintaining healthy brain processes and supporting cognitive functions that are particularly vulnerable in individuals with dementia. Emerging evidence suggests that alterations in sleep may serve as early biological markers of cognitive decline, appearing before observable impairments in memory and learning. People with dementia frequently exhibit extended total sleep time and disruptions in sleep architecture. In particular, changes in non‑rapid eye movement (NREM) and rapid eye movement (REM) sleep are increasingly recognized as sensitive indicators of cognitive deterioration. Although sleep disturbances in dementia are well documented, less is known about how specific elements of sleep architecture, especially deep sleep, change as cognitive impairment progresses from mild to severe stages. This study seeks to investigate differences in sleep architecture across varying levels of cognitive decline, from mild impairment to advanced dementia. As part of the larger and ongoing project (2024-2028) Decoding Death and Dying in people with Dementia using Digital thanotyping (5-D), this study was conducted in Norwegian nursing homes. Participants (n=123, >64 years of age) were recruited based on cognitive impairment, and assessed by the clinical dementia rating scale (CDR), with inclusion criteria of CDR ≥ 1. Somnofy environmental sensor (VitalThings AS, Norway) was used to detect sleep parameters.Our results suggest that changes in sleep progress as cognitive decline advances. Higher degree of cognitive decline was associated with reduced sleep efficiency and less deep sleep. No significant changes were observed for light sleep or REM sleep. Further analysis is required for exploration of these changes.