1023 Infraslow Oscillations During Sleep in Long-Term Survivors of Pediatric Hodgkin's Lymphoma

Abstract Introduction The locus coeruleus (LC) is a primary source of noradrenaline (NA), which plays a key role in arousal, attention, and memory function. Evidence suggests that the fluctuation of NA on an infraslow timescale of ~50s can be tracked by changes in electroencephalographic (EEG) sigma power (ISFS, ~0.02 Hz) during non-rapid-eye movement sleep (NREM). Adult survivors of childhood Hodgkin’s Lymphoma (HL) have increased incidence of sleep disturbance and cognitive dysfunction, as well as many demonstrating autonomic nervous system dysfunction. Due to the role of LC-NA signaling in cognitive function, we conducted an exploratory analysis to evaluate the sleep dynamics of ISFS in HL survivors compared to healthy controls. Methods A retrospective analysis was conducted on St. Jude Lifetime Cohort Study. Participants completed two nights of home-polysomnography (PSG) and the Pittsburgh Sleep Quality Index (PSQI). The PSG recording containing the greatest number of 5-minute sections of Stage 2 sleep (NREM2) was selected for each participant. HL survivors (N=139) and community controls (N=119) were matched by sex, race, and BMI. EEG sigma power (12–16 Hz) time-course was computed by averaging the frequency decomposition of 5-minute NREM2 sections. ISFS dynamics including bandwidth, peak frequency, peak power, and area under the curve (AUC) were estimated using the power spectral density. Spindle events were further identified. Linear regression models compared survivors and community controls, adjusting for age, sex, race, and BMI. Results Compared to controls, survivors reported worse sleep quality (PSQI; survivor: 7.25±4.2, control: 5.36±2.7, p< 0.001), and had ISFS higher peak power (β=917×10-3, p=0.002) and AUC (β=15×10-3, p< 0.001). No differences in ISFS frequency (β=-146×10-6, p=0.630) nor bandwidth (β=375×10-6, p=0.340) were observed. ISFS dynamics were not correlated with PSQI. Spindle density, sleep time, and duration of NREM2 did not differ among survivors and controls. Conclusion Our findings suggest variable autonomic regulation during sleep in HL survivors, characterized by intensified ISFS potentially linked to increased spindle clustering. Since spindle-rich ISFS peaks have been previously associated with arousal regulation and memory consolidation, this may represent a neurophysiological marker of cognitive function among survivors. Future research should investigate ISFS as a potential mechanism of cognitive function. Support (if any)