# Dynamics between Sleep Pattern and Behavioral and Psychological Symptoms of Dementia (BPSD)

## TL;DR

This study shows that sleep disturbances in older adults with dementia can predict and worsen behavioral and psychological symptoms the next day, creating a harmful cycle.

## Contribution

The study introduces a bidirectional dynamic relationship between sleep disturbances and BPSD using time series analysis.

## Key findings

- Increased awakenings during sleep predict irritability and eating disorders the next day.
- Delusions among BPSD worsen sleep patterns, increasing total sleep time and awakenings.
- Irritability and sleep awakenings show bidirectional causality, forming a vicious cycle.

## Abstract

A higher prevalence of behavioral and psychological symptoms of dementia (BPSD) is associated with a higher care burden in caregivers and increased mortality in people living with dementia. However, from the perspective that unmet needs trigger BPSD, there is a lack of time series analysis on whether sleep disturbances can predict the occurrence of BPSD the following day. In this study, older adults with dementia wore an actigraphy device on their wrists continuously for two weeks for sleep data, and caregivers recorded BPSD in a daily symptom diary for two weeks. The panel vector autoregression model analyzed data from 154 older adults living with dementia and their caregivers and found that the previous day’s awakenings during sleep had a significant effect on irritability and appetite or eating disorders. Conversely, some symptoms of BPSD, including delusions, had significant effects on the next day’s sleep patterns, resulting in increases in total sleep time, number of awakenings, and mean awakening length. In particular, irritability among BPSD was found to have a bidirectional causality with number of awakenings. This study demonstrates that the relationship between BPSD and sleep patterns is dynamic, characterized by a vicious cycle. Consequently, early intervention to alleviate symptoms is imperative, and strategies to enhance sleep quality should be prioritized during the initial stages when sleep patterns are disturbed.