Practice parameters for the use of actigraphy in the military operational context: the Walter Reed Army Institute of Research Operational Research Kit-Actigraphy (WORK-A)

Abstract

Background: The Walter Reed Army Institute of Research (WRAIR) Operational Research Kit-Actigraphy (WORK-A) is a set of unique practice parameters and actigraphy-derived measures for the analysis of operational military sleep patterns. The WORK-A draws on best practices from the literature and comprises 15 additional descriptive variables. Here, we demonstrate the WORK-A with a sample of United States Army Reserve Officers' Training Corps (ROTC) cadets (n = 286) during a month-long capstone pre-commissioning training exercise. Methods: The sleep of ROTC cadets (n = 286) was measured by Philips Actiwatch devices during the 31-day training exercise. The preliminary effectiveness of the WORK-A was tested by comparing differences in sleep measures collected by Actiwatches as calculated by Philips Actiware software against WORK-A-determined sleep measures and self-report sleep collected from a subset of ROTC cadets (n = 140). Results: Actiware sleep summary statistics were significantly different from WORK-A measures and self-report sleep (all P ≤ 0.001). Bedtimes and waketimes as determined by WORK-A major sleep intervals showed the best agreement with self-report bedtime (22:21 ± 1:30 vs. 22:13 ± 0:40, P = 0.21) and waketime (04:30 ± 2:17 vs. 04:31 ± 0: 47, P = 0.68). Though still significantly different, the discrepancy was smaller between the WORK-A measure of time in bed (TIB) for major sleep intervals (352 ± 29 min) and self-report nightly sleep duration (337 ± 57 min, P = 0.006) than that between the WORK-A major TIB and Actiware TIB (177 ± 42, P ≤ 0.001). Conclusions: Default actigraphy methods are not the most accurate methods for characterizing soldier sleep, but reliable methods for characterizing operational sleep patterns is a necessary first step in developing strategies to improve soldier readiness. The WORK-A addresses this knowledge gap by providing practice parameters and a robust variety of measures with which to profile sleep behavior in service members.

Pilot Sleep Behavior across Time during Ultra-Long-Range Flights

“…Estimations of daily sleep duration were further limited due to the fact that flights departed Brazil at variable hours of the day and crossed multiple time zones continuously throughout the mission. Parameters for "daily" estimations of sleep are normally defined with hourly cutoffs, such as noon to noon [24]. These cutoffs could have been retained using Brazil time (UTC-5) except that 3 of the 5 missions departed in the afternoon while 2 departed shortly after midnight.…”

“…This constitutes a limitation to sleep research in general, and closing the validation gap is a goal for future research [34]. Previous studies have compared self-report to actigraphy but these comparisons have been made either under controlled conditions or in specialty populations that are not directly comparable to airline pilots [24,[28][29][30]32,35]. Explained variance between measures of sleep duration or timing have been reported in these previous studies.…”

Sleep Depth and Patterns of In-Flight Sleep Behavior Across Time During Global Pandemic Conditions

“…Validation testing methodology has been established for a laboratory environment [25], but there is little guidance for what constitutes proper validation of sleep measurement in a real-world environment. Previous studies have compared self-report to actigraphy [26][27][28], but it is impossible to say whether the subjective assessment of sleep or the objective measurement is more representative of actual sleep under the circumstances of testing in the field.…”

Validation of Zulu Watch against Polysomnography and Actigraphy for On-Wrist Sleep-Wake Determination and Sleep-Depth Estimation

“…Supplementary data sources, such as sleep diaries or daily schedules, as well as hand scoring EBE data, are recommended for any research or clinical use of actigraphy [ 9 ]. Supplementary measures may not always be practical to collect in operational research settings like the military, aviation, or shift work because they may increase the burden of data collection in a safety-sensitive environment [ 10 ]. This constitutes a limitation in the field of ecological sleep research technology in general.…”

“…Its application to operational environments requires significant additional data processing. While the practice parameters for the clinical or research use of actigraphy in healthy individuals, sleep-disordered populations, or military operational contexts have been published [ 8 , 9 , 10 ], these guidelines still encourage hand scoring of data to achieve the highest levels of accuracy, and there is no resolute consensus on the scoring methodology [ 11 , 12 ].…”