Disrupted Sleep and Circadian Rhythm Associations in Sleep-Deprived TBI Patients
Angeliki Pollatou, PhD, Elizabeth Metzger MSPH, J. Kent Werner, Jr., MD, PhD
Traumatic brain injury (TBI) alters sleep architecture and circadian rhythms, exacerbating cognitive and physiological impairments. Sleep deprivation, a common stressor in military and civilian populations, disrupts these systems. This study examined interactions between sleep and circadian metrics in sleep-deprived TBI and non-TBI participants to identify disruption patterns. Twenty-five participants, including individuals with and without TBI (N=16), were monitored at home for two weeks using the Oura ring to derive circadian parameters such as acrophase and mesor through cosinor analysis of skin temperature. Midsleep time was calculated from Oura ring data. Following 36 hours of sleep deprivation, participants underwent in-lab polysomnography (PSG). Metrics like wake after sleep onset (WASO), sleep onset latency (SOL) and REM/NREM sleep epochs were derived from visual scoring. Circadian and PSG parameters were compared, and linear regression interaction models evaluated how TBI moderates relationships between circadian and sleep metrics (b3: interaction effect). TBI patients demonstrated significantly earlier circadian timing at home, with acrophase at 1:55 AM compared to 3:02 AM in non-TBI participants (p<0.05). TBI status significantly moderated the relationship between acrophase and midsleep timing (b3=-0.5, p=0.033), reflecting disrupted circadian alignment. No significant group differences were observed in the PSG parameters estimated. Wearable devices may reveal circadian disruptions missed by in-lab sleep studies. Sleep-deprived TBI participants exhibited disrupted circadian and sleep integration, including earlier circadian timing, weakened alignment between midsleep and acrophase, and altered relationships with restorative NREM sleep. These findings highlight the need for interventions addressing circadian and sleep dysfunctions in this population.
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