Sleep

Digital markers and phenotypes of rest-activity rhythms in people with advanced dementia using real-time location data.

TL;DR

Real-time location system (RTLS) technology can derive digital markers and phenotypes of rest-activity rhythms in people with advanced dementia, with RTLS-derived markers associated with clinical assessments of motor agitation and sleep disruption over time.

Key Findings

Wrist-worn RTLS devices successfully tracked continuous location data for up to 16 weeks in people with advanced dementia in residential care.

  • Study enrolled 47 participants, including 21 women, with a mean age of 80.1 years
  • Participants resided on a specialized dementia unit
  • Distance moved in 15-minute windows was used to derive digital markers
  • Both parametric and non-parametric features were derived from the location data

Higher RTLS-derived activity intensity was correlated with increased clinical motor agitation scores.

  • Panel and mixed-effect models were used to investigate relationships between clinical assessments and RTLS-based digital markers
  • The association held across longitudinal assessments over the study period
  • This suggests RTLS activity intensity may serve as a proxy measure for motor agitation in this population

Disrupted rhythmicity and reduced time in bed were associated with difficulty falling asleep and increased nighttime motor agitation.

  • Decreased rhythmicity was linked to both sleep onset difficulty and nighttime motor agitation
  • Less nighttime time in bed was specifically associated with higher motor agitation and sleep disruption
  • These relationships were identified using panel and mixed-effect models accounting for repeated measures

Unsupervised machine learning identified 6 distinct rest-activity phenotypes over 1-week periods in people with advanced dementia.

  • The six phenotypes identified were: high time in bed, well-regulated, low stability, severe rhythm disturbance, nighttime active, and highly active individual
  • Phenotypes were derived from RTLS data using unsupervised clustering methods
  • Phenotypes were assessed over 1-week periods, allowing for longitudinal tracking of phenotype transitions

The six RTLS-derived rest-activity phenotypes differed significantly by age, cognition, mood disturbance, and functional status.

  • Clinical dimensions differentiating phenotypes included age, cognitive status, mood disturbance, and functional status
  • This suggests phenotypes capture clinically meaningful differences in dementia presentations
  • The phenotype framework provides a data-driven approach to characterizing heterogeneous rest-activity patterns in this population

RTLS-derived rest-activity markers and phenotypes were associated with changes in clinical assessments over time.

  • Longitudinal associations between RTLS markers and clinical assessments were demonstrated over the up-to-16-week monitoring period
  • Changes in activity intensity, rhythmicity, and nighttime time in bed tracked with changes in motor agitation and sleep disruption
  • Authors conclude that RTLS markers 'may support data-driven, evidence-based dementia care'

What This Means

This research suggests that small wrist-worn tracking devices — the kind already used in care facilities to locate residents and prevent wandering — can also provide meaningful information about sleep and activity patterns in people with advanced dementia. By measuring how far residents moved every 15 minutes over up to 16 weeks, the researchers were able to calculate digital measures of rest and activity rhythms. They found that these measures were linked to clinical observations: residents who were more active overall tended to show more physical agitation, and those with more disrupted or irregular rhythms had more trouble falling asleep and more nighttime restlessness. Using a machine learning approach, the researchers also identified six distinct 'types' of rest-activity patterns — ranging from spending a lot of time in bed, to having well-regulated rhythms, to being highly active or predominantly active at night. These groups differed in meaningful ways: they were associated with differences in age, cognitive ability, mood, and physical function. This suggests that dementia affects sleep and activity patterns in several different ways, and that one-size-fits-all care approaches may not be appropriate. This research suggests that repurposing existing location-tracking technology in care facilities could allow staff to continuously and passively monitor residents' rest-activity patterns without additional burden on residents or staff. Over time, this could help identify when a resident's condition is changing, support more personalized care decisions, and provide objective data to complement traditional clinical assessments in people with advanced dementia who may not be able to self-report their symptoms.

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Citation

Karam Y, Shum L, Faruk T, Arora T, McArthur C, Chu C, et al.. (2026). Digital markers and phenotypes of rest-activity rhythms in people with advanced dementia using real-time location data.. The journals of gerontology. Series A, Biological sciences and medical sciences. https://doi.org/10.1093/gerona/glaf288