0847 The Role of Pulse Wave Amplitude in Detecting Arousals in Children with Hypersomnia

Abstract Introduction Changes in pulse wave amplitude (PWA) are a sensitive marker for both cortical and autonomic arousals, and are readily available in conventional polysomnogram recordings. The aim of the current study was to examine electrocortical versus PWA-based arousals in pediatric patients being evaluation for disorders of central hypersomnolence. Methods Polysomnograms for thirty consecutive patients who underwent multiple sleep latency test (MSLT) were identified. A drop in PWA signal of at least 30% that lasted for 3 seconds was needed to identify arousals. Arousals on overnight polysomnogram were rescored based on PWA drop. Patients were classified based on MSLT results into 3 groups: Narcolepsy group if mean sleep latency 8 minutes and the presence of 2 or more sleep onset rapid eye movement periods (SOREMP); idiopathic hypersomnia (IH) group if mean sleep latency 8 minutes and less than 2 SOREM periods; or normal if they did not meet criteria for narcolepsy or IH. Group differences in electrocortical arousal index (AI) vs PWA-based arousal index were examined via ANOVA. Results Out of the 30 patients included, there were 19 patients with normal MSLT, 7 patients with narcolepsy, and 4 patients with IH. There were no significant between-group differences for age, total sleep time (TST), sleep efficiency (SE), sleep latency (SL), REM latency, N1, N2, N3 or REM percentages, apnea hypopnea index (AHI), or periodic limb movement index (PLMI). There was were no significant differences between electrocortical AI in normal (9.4+/-4.4), IH (9.1/hr+/-4.9), and narcolepsy (10.6+/-6.6) groups (F(2,27)=0.156, p=0.857). In contrast, there statistically significant between-group differences in PWA-based AI (F(2,27=3.765, p=0.036). Post-hoc analysis demonstrated higher PWA-based AI in narcolepsy vs normal (24.2+/-10.4 vs 16.2+/-5.3, p=0.017), a trend for higher levels in IH vs normal (22.3+/-8.5 vs 16.2+/-5.3, p=0.131), and no difference between narcolepsy and hypersomnia groups (24.2+/-10.4 vs 22.3+/-8.5, p=0.674). Conclusion Pulse wave amplitude may hold promise as a scoring tool to help identify arousals and sleep disruption in patients with central disorders of hypersomnolence. Further studies are needed to verify these preliminary results and explore the utility of PWA-based AI in other sleep disorders. Support (if any)