1166 POOR SLEEP IS ASSOCIATED WITH MORNING HIGH SYMPATHETIC ACTIVITY AND LOW PARASYMPATHETIC ACTIVITY IN RESTING NEUROTYPICAL AND AUTISTIC ADULTS

Abstract

Individuals with autistic spectrum disorder (ASD) display higher sympathetic activity during wakefulness. In typically developing individuals (TD) higher sympathetic activity is observed in the morning compared to evening levels. The main objectives of this study were to compare autonomic nervous system (ANS) activity during wakefulness in the evening and in the morning in a group of adults with ASD and a group of TD adults, as well as to explore the association between ANS activity and self-reported sleep measures. The electrocardiogram of 33 adults (16 ASD; 17 TD) was recorded during wakefulness, before and after a night of sleep. The following heart rate variability (HRV) parameters were measured: low (LF) frequencies, high frequencies (HF) and total spectral power. Values were compared between groups using two-way ANOVAs (ASD vs TD) and one repeated measure (Evening vs Morning). Pearson correlations coefficients between self-reported sleep measure and morning HRV parameters were calculated. Compared to the TD group, the ASD group displayed significantly lower morning HF values (34.98 ± 20.55 vs. 53.35 ± 22.17) and higher LF/HF ratios (1.52 ± 2.22 vs. 3.02 ± 2.28) compared to the TD group. No group differences were observed in the evening. When all participants were pooled together, longer nocturnal awakenings and lower sleep efficiency were correlated with higher sympathetic activity (respectively r = 0.52; p<0.01 and r = -0.43; p=0.04) and lower parasympathetic activity (respectively r= -0.54; p<0.01 and r = 0.42; p = 0.04) in the morning. 1) A higher morning sympathovagal balance prevails in ASD compared to TD individuals; 2) This is associated with self-reported markers of poor sleep. Canadian Institutes of Health Research and “Fonds de la recherche du Québec en santé”.