Sleep-wake dynamics in veteran-service dog dyads: an exploration of overnight concordance

Sleep disturbances are well-documented for veterans with posttraumatic stress disorder. Increasingly, veterans are turning to service dogs for assistance. Service dogs may positively influence veteran sleep. However, there is a need for research that considers bidirectional sleep interactions at the dyad level. Our objective was to investigate overnight sleep-wake dynamics in veteran-service dog dyads.

Fifty-six veteran-service dog dyads contributed data for analysis. Standardized questionnaires were captured at baseline (veteran well-being, prior to service dog partnering) and at 3-month follow-up (dyad bond and well-being). Fourteen days of actigraphy (1 min epochs) and ecological momentary assessment (twice daily) were collected at follow-up. We calculated sleep-wake concordance (percent agreement; 0% to 100%) and activity concordance (Stuart-Kendall Tau-c; -1.0 to 1.0) from 650 nights of actigraphy data, including 289 749 min-level observations.

Based on a nightly average, veteran-service dog dyads had 79% sleep-wake concordance (range 63% to 88%) and 0.04 activity concordance (range -0.02 to 0.15). Service dogs exhibited higher sensitivity to veteran wakefulness (28%; range 9% to 82%) than veterans to service dogs (11%; range 4% to 21%). Regression analyses found no consistent relationships between concordance and measures of veteran-service dog bond or well-being.

Veteran-service dog dyads demonstrate sleep-wake concordance rates comparable to those reported in other close relationships (e.g. mother-infant, couples), and service dogs appear more sensitive to veteran wakefulness than the other way around. This novel investigation offers a framework for future research on human-service dog overnight dynamics, emphasizing the mutual attunement of veterans and their service dogs. Statement of Significance This study explores high-fidelity overnight sleep-wake dynamics in an interspecies context, focusing on veteran-service dog dyads. We analyzed data simultaneously collected from both the humans and service dogs. We found that these unique partnerships exhibited sleep-wake concordance (e.g. alignment in sleep and wake episodes) at rates similar to other close relationships, such as couples as well as parents and children. However, concordance was not associated with self-reported bond strength, veteran well-being, or service dog well-being. Future research should explore concurrent physiological measures (e.g. heart rate, blood pressure, respiration rate, skin temperature, and cortisol levels), which may provide more sensitive indicators of stress and well-being. Overall, our findings enhance our understanding of the complex overnight dynamics of service dog teams.