INSIGHT: Insomnia, Nightmares, and Sympathetic Hyperactivity Intervention

Plain-language summary

The INSIGHT study is a multi-site clinical research program designed to examine how insomnia and symptoms of sympathetic hyperactivity impair sleep, cognition, and physiological restoration in warfighters, and to evaluate whether a wearable therapeutic device can improve these outcomes. Warfighters with a history of traumatic brain injury, post-traumatic stress disorder, or chronic operational stress commonly report disrupted sleep accompanied by manifestations of nocturnal sympathetic activation such as diaphoresis, palpitations, hyperarousal, and nightmares. These symptoms erode sleep quality, reduce cognitive performance, and undermine psychological resilience and operational readiness. Insomnia is two to three times more common in military populations than in civilians, and both TBI and PTSD independently elevate the risk for dysregulated autonomic tone. Excessive sympathetic activity during REM sleep disrupts the normally quiescent locus coeruleus state required for adaptive emotional processing and may contribute to the genesis of nightmares. Excessive sympathetic tone may also interfere with deep NREM-dependent glymphatic clearance, a recently discovered mechanism that supports cognitive restoration and metabolic waste removal. Yet, no study has comprehensively linked these physiological processes in warfighters or evaluated whether wearable-derived autonomic measures can meaningfully stratify insomnia phenotypes. The INSIGHT protocol addresses this gap through a two-phase design integrating multimodal biomarker collection, wearable technology validation, advanced imaging, and a randomized controlled intervention. Phase 1 enrolls 250 participants (50 healthy controls and 200 poor sleepers with or without PTSD and TBI) who undergo structured screening, cognitive testing, and detailed baseline assessments before completing a 2-week at-home data collection period. During this period, participants wear a suite of devices, including EEG headbands, ECG patches, PPG-based sensors, accelerometry rings, blood pressure devices, temperature sensors, and smartwatches, to capture autonomic activity, sleep architecture, cardiovascular and respiratory variability, movement, sudomotor activity, and circadian body temperature patterns. Ecological momentary assessments administered three times daily track fluctuations in sleep quality, mood, PTSD symptoms, and daytime functioning, while urine samples collected on the final three days allow for biochemical analysis of hormonal and sympathetic biomarkers. After the at-home period, all participants complete an overnight in-lab polysomnogram combined with fNIRS to measure sleep stages, autonomic dynamics, cerebral hemodynamics, and glymphatic signatures. A subset of participants also completes an optional overnight MRI with simultaneous EEG following controlled sleep deprivation, enabling state-of-the-art imaging of human glymphatic activity using the MAGNUS MRI platform. This optional visit provides unprecedented insight into how TBI, PTSD, and insomnia alter the physiology of sleep-dependent brain fluid dynamics. In Phase 2, all poor sleepers enter a double-blind, sham-controlled, 30-day randomized trial testing the therapeutic potential of the NightWare smartwatch. NightWare detects sympathetic surges during sleep through heart rate elevations and movement patterns and delivers brief haptic vibrations aimed at interrupting escalating autonomic arousal. Although originally cleared for nightmare treatment, its mechanism is well suited for SNH-related insomnia more broadly. Participants use the device daily while continuing EMA surveys, wearable monitoring, and cognitive assessments, generating rich physiological and behavioral data throughout the intervention. The primary goal is to determine whether reducing nocturnal sympathetic spikes leads to measurable improvements in sleep quality, autonomic stability, daytime functioning, and symptom burden. In parallel, Phase 2 data enable development of the Multi-Organ Autonomic Index of Sleep, an integrated biomarker model that combines neurological, cardiovascular, respiratory, and dermal signals to predict treatment response and classify insomnia subtypes. The INSIGHT study will produce the most comprehensive dataset to date linking autonomic physiology, glymphatic function, sleep architecture, wearable-derived biomarkers, cognition, and clinical outcomes in warfighters. By identifying physiological signatures of sympathetic hyperarousal and determining whether a non-pharmacological wearable intervention can meaningfully improve sleep, INSIGHT directly supports Department of Defense priorities to enhance readiness, resilience, and long-term neurological health in service members. Wearable tools capable of monitoring and improving sleep outside the laboratory have the potential to transform both clinical care and operational performance, offering scalable and accessible approaches to restoring sleep and optimizing recovery.

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Trial details