Related Experiment Video
Updated: Apr 15, 2026

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
Published on: August 8, 2019
The Feasibility of Home-Based Estimation of Circadian Timing in Veterans With Insomnia and Past Traumatic Brain
Daniel J Reis1, Adrieann E Armstrong, Christin Miller
1Author Affiliations: VA Rocky Mountain Mental Illness Research, Education, and Clinical Center for Veteran Suicide Prevention (Reis, Armstrong, Miller, Postolache, Forster, and Bahraini), Aurora, Colorado; Department of Psychiatry (Reis, Brenner, and Bahraini), University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physical Medicine and Rehabilitation (Forster, Brenner, and Bahraini), University of Colorado Anschutz Medical Campus, Aurora, Colorado; VISN 5 Capitol Health Care Network Mental Illness Research Education and Clinical Center (Postolache), Baltimore, Maryland; Department of Psychiatry (Postolache), University of Maryland School of Medicine, Baltimore, Maryland; Department of Neurology (Brenner), University of Colorado Anschutz Medical Campus, Aurora, Colorado; and VA Brain Health Coordinating Center (Brenner), Aurora, Colorado.
Objective:
To evaluate the feasibility and acceptability (eg, user experience) of 2 methods for home-based estimation of circadian timing among veterans with insomnia and a history of traumatic brain injury (TBI).
Setting:
An outpatient setting at a Department of Veterans Affairs medical center.
Participants:
Veterans between the ages of 18 and 64 years with current insomnia and a history of mild-to-severe TBI.
Design:
A prospective observational study evaluating the feasibility of 2 home-based methods for estimating circadian timing, that is, dim light melatonin onset (DLMO): (1) indirect prediction of DLMO using activity and light-exposure data collected through actigraphy (ie, pDLMO); and (2) estimation of DLMO via direct measurement of melatonin in self-collected salivary samples (ie, salivary DLMO). Participants wore an actigraphy device and completed sleep diaries for one week. They then spent one evening self-collecting 7 saliva samples under dim light conditions. Finally, participants completed a brief qualitative interview on their experiences.
Main Measures:
Primary outcomes were the success rates for estimation of each home-based DLMO method. Feasibility was set as 70% successful estimation for a given measure, for those who completed the respective procedures.
Results:
pDLMO could be estimated for 27 of 29 participants (93.1%) who completed actigraphy data collection, meeting the feasibility goal. Salivary DLMO could only be estimated for 7 of 28 participants (25%) who completed saliva collection. Participants broadly expressed acceptance of both home-based DLMO methods and a willingness to use them again. Several barriers related to each method were identified that can inform future implementation efforts with this patient population.
Conclusion:
pDLMO is feasible and acceptable for estimating circadian timing in veterans with insomnia and past TBI. Using pDLMO could help identify circadian-sleep misalignment after TBI, helping personalize insomnia treatments based on patient-specific needs and interrupting the bidirectional cycle of insomnia and circadian dysregulation.
Related Concept Videos
Management of Insomnia
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...

