THE CIRCADIAN MISALIGNMENT IS ASSOCIATED WITH REDUCED SLOW-WAVE SLEEP IN INDIVIDUALS WITH AUTISM SPECTRUM DISORDER

Abstract Introduction Sleep disturbances are one of the key features among individuals with autism spectrum disorder (ASD). Many studies have uncovered critical developmental links between cognition, behavior, and sleep. It is suggested that the circadian system desynchronization plays a vital role in the development of ASD. While research on sleep disruption and circadian disturbance has accumulated, only a few studies have investigated a relationship between sleep architecture and circadian rhythm of individuals with ASD to date. We aim to elucidate the relation using the methods of dim light melatonin onset (DLMO) and ambulatory PSG. Methods Eleven individuals with autism (3 females, age: 13.07 ± 4.76 years; age range: 8-23 years) were recruited. After a week of systematic desensitization, an ambulatory overnight PSG was conducted in the participant’s home. Participants collected saliva samples independently at home on two consecutive days. The first evening sample took place 3 hours before the average sleep onset time and continued each 30-minute interval afterward for a total of 5 evening samples. The DLMO was calculated for each day by plotting melatonin levels against the time of saliva sampling. Linear regression was used to determine the best-fit line equation for each plot to calculate when melatonin levels first reached 4 pg/mL and continued to rise. Results The percentage of Stage N3 sleep across the night was significantly negatively associated with phase angle (time between DLMO and sleep onset), revealing that Stage N3 percentage decreases as the phase angle increases. The Phase angle showed a significant positive association with REM percentage across the night. Additionally, a significant difference was found between the mean phase angle for the ASD subjects in this study and the mean phase angle expected from a group of age-matched, typically developing (TD) individuals. Conclusion Our data revealed that circadian misalignment in individuals with ASD is associated with sleep architecture characterized by reduced slow-wave sleep and increased REM sleep. Given the importance of slow-wave sleep for memory and cognitive functions, this finding may contribute to understanding the relationship between sleep alterations and brain development in ASD. Support (If Any)