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)

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(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)min,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.