---
title: BPSD — Sleep disorder
type: concept
last_updated: 2026-04-25
sources:
  - code/kb_loader/data/clinical/bpsd/sleep_disorder.json
status: settled
---

# Sleep disorder

Sleep–wake fragmentation is near-universal in AD. Often comorbid with [sundowning](bpsd_sundowning.md).

## Sensor signature

- **IMU:** night-time activity surges, reduced consolidated sleep blocks
- **PPG:** night-time HR fluctuations, possible apnea episodes (SpO₂ dips)
- **EDA:** elevated nocturnal SCL during arousals

## Why this project tracks it

- Sleep fragmentation accelerates cognitive decline.
- Sleep–wake reversal is a quality-of-life burden for caregivers.
- PPG+IMU sleep staging is non-PSG-grade but adequate for trend tracking.

## Intervention

Light exposure regulation, structured day, evening routine; medical evaluation for OSA if SpO₂ pattern suggests it. See [Intervention agent](../agents/intervention_agent.md).

KB: [`code/kb_loader/data/clinical/bpsd/sleep_disorder.json`](../../code/kb_loader/data/clinical/bpsd/sleep_disorder.json). Umbrella: [BPSD](bpsd.md).