Assessing Night-to-Night Sleep Variability as a Hallmark of Chronic Insomnia Using Longitudinal, Contactless, Mobile Sleep Monitoring: Prospective Cohort Study.
Hansen D, Peterson M, et al. • JMIR formative research • 2026
Persistent night-to-night variability in objective sleep measures is a hallmark of chronic insomnia, as demonstrated by the longest known objective characterization of sleep among individuals with chronic insomnia using a contactless, radio frequency-based sleep monitoring device.
Key Findings
Results
Individuals with chronic insomnia exhibited reduced sleep efficiency compared to healthy good-sleeper controls over 8 weeks of home-based monitoring.
83 participants meeting criteria for chronic insomnia and 29 healthy good-sleeper controls were enrolled
Monitoring was conducted over 8 consecutive weeks in participants' home environments
Sleep efficiency was objectively quantified as daily means and standard deviations using a contactless, radio frequency-based device
Differences in sleep efficiency between groups were statistically significant (P<.001)
Results
Individuals with chronic insomnia showed increased sleep latency compared to healthy controls.
Sleep latency was measured objectively using a contactless radio frequency-based device across 8 weeks
The difference in sleep latency between insomnia and control groups was statistically significant (P<.001)
Measurements were taken in naturalistic home environments to ensure ecological validity
Sleep latency was quantified as both daily means and standard deviations
Results
Individuals with chronic insomnia demonstrated increased intermittent wakefulness compared to healthy good-sleeper controls.
Intermittent wakefulness was objectively measured over 8 consecutive weeks of nightly monitoring
The difference between insomnia and control groups was statistically significant (P<.001)
Measurements captured intermittent wakefulness in participants' typical sleep environments
Intermittent wakefulness was quantified as both a daily mean and standard deviation across the monitoring period
Results
Individuals with chronic insomnia exhibited significantly higher night-to-night variability in sleep efficiency, sleep latency, and intermittent wakefulness than good-sleeper controls.
Night-to-night variability was quantified using standard deviations of nightly sleep measures
Higher variability was observed across all three sleep measures: sleep efficiency, sleep latency, and intermittent wakefulness
All differences in variability between groups were statistically significant (all P<.001)
This finding supports night-to-night variability as 'a hallmark of chronic insomnia'
Results
A contactless, radio frequency-based sleep monitoring device accurately distinguished healthy good sleepers from individuals with chronic insomnia in a naturalistic home setting over an extended period.
This is described as 'the longest known objective characterization of sleep among individuals with chronic insomnia'
The study monitored participants for 8 consecutive weeks in their typical sleep environments
The device measured sleep efficiency, sleep latency, intermittent wakefulness, time in bed, and total sleep time
The study design was a prospective cohort with 83 insomnia participants and 29 healthy controls
Contactless monitoring allowed for ecologically valid, objective assessment without requiring wearable sensors
Background
Chronic insomnia affects more than 30% of US adults and is more prevalent in women and older adults.
The condition is strongly associated with poor mental and physical health outcomes
Longitudinal assessment of sleep has been largely subjective prior to this study
No prior objective characterization of sleep patterns and intraindividual variability over extended periods had been established
Consumer sleep technologies were identified as a potential solution with relatively unexplored clinical utility
What This Means
This research suggests that people with chronic insomnia don't just sleep worse on average — their sleep quality fluctuates dramatically from night to night in ways that clearly distinguish them from people who sleep well. Using a device placed in participants' bedrooms that monitors sleep wirelessly (without any wearable sensors), researchers tracked the sleep of 83 people with chronic insomnia and 29 healthy sleepers every night for 8 weeks. People with insomnia had worse sleep efficiency, took longer to fall asleep, and woke up more during the night compared to good sleepers. Critically, their sleep was also far more unpredictable night to night — some nights might be somewhat tolerable while others were very poor — whereas good sleepers had much more consistent nightly sleep patterns.
This study is notable because it is described as the longest objective, in-home sleep study of people with chronic insomnia ever conducted. Most prior research relied on people's own reports of their sleep, which can be inaccurate, or used clinical sleep lab tests that only capture one or a few nights and don't reflect real home conditions. By using a contactless device in participants' own bedrooms over two months, this research captured a more realistic and complete picture of what insomnia actually looks like over time.
This research suggests that night-to-night sleep variability — not just average poor sleep — is a defining characteristic of chronic insomnia. This could have implications for how insomnia is identified and tracked, potentially supporting the use of consumer sleep technology devices in clinical settings to monitor sleep patterns over time, rather than relying solely on short-term or self-reported assessments.
Hansen D, Peterson M, Finlay M, Gottlieb E, Danoff-Burg S, Raymann R, et al.. (2026). Assessing Night-to-Night Sleep Variability as a Hallmark of Chronic Insomnia Using Longitudinal, Contactless, Mobile Sleep Monitoring: Prospective Cohort Study.. JMIR formative research. https://doi.org/10.2196/73969