Assessing Night-to-Night Sleep Variability as a Hallmark of Chronic Insomnia Using Longitudinal, Contactless, Mobile Sleep Monitoring: Prospective Cohort Study

TL;DR

This study shows that night-to-night sleep variability is a key sign of chronic insomnia, using a contactless device to track sleep over 8 weeks in real homes.

Contribution

The study introduces the first long-term, objective, contactless sleep monitoring of chronic insomnia in natural home settings.

Findings

Insomnia patients had lower sleep efficiency and higher sleep latency than healthy controls.

Night-to-night variability in sleep metrics was significantly higher in insomnia patients.

Contactless radio frequency devices can accurately detect insomnia in home environments.

Abstract

Chronic insomnia affects more than 30% of US adults, is more prevalent in women and older adults, and is strongly associated with poor mental and physical health outcomes. Poor sleep quality and intraindividual variability of sleep are recognized to be key characteristics of chronic insomnia, but longitudinal assessment of sleep is largely subjective, with no objective characterization of sleep patterns and intraindividual variability over extended periods. Objective, ecologically valid longitudinal sleep measurements are needed to help identify and manage insomnia in both clinical and population settings. Consumer sleep technologies offer a possible solution, but their clinical utility remains relatively unexplored.

We aimed to evaluate the utility of a contactless, radio frequency–based device by demonstrating its ability to objectively characterize sleep in individuals with insomnia over an extended observation period in a naturalistic home environment.

Eighty-three participants meeting criteria for chronic insomnia and 29 healthy good-sleeper controls underwent 8 consecutive weeks of home-based sleep monitoring using an objective, contactless, radio frequency–based sleep monitoring device. Sleep efficiency, sleep latency, intermittent wakefulness, time in bed, and total sleep time were objectively quantified as daily means and SDs.

Compared to healthy controls, individuals with chronic insomnia exhibited reduced sleep efficiency, increased sleep latency, and increased intermittent wakefulness. They also demonstrated significantly higher night-to-night variability (SDs) in sleep efficiency, sleep latency, and intermittent wakefulness than good-sleeper controls (all P<.001).

In the longest known objective characterization of sleep among individuals with chronic insomnia, we show that a radio frequency–based, contactless sleep monitoring device deployed in the participants’ typical sleep environments accurately distinguished healthy good sleepers from those with insomnia. Importantly, we show that persistent night-to-night variability in objective sleep measures is a hallmark of chronic insomnia.

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