Abstract
OBJECTIVES: The brain and autonomic nervous system are tightly interconnected and may be involved in various psychiatric conditions. We explored whether electroencephalographic (EEG) coherence and vagally mediated heart rate variability (vmHRV) differ between male children with autism spectrum disorder (ASD) and typically developing (TD) children, and how these measures are associated with the clinical characteristics of ASD. METHODS: We recorded resting-state EEG and vmHRV in 14 male children with ASD and 14 TD children. The Social Responsiveness Scale (SRS) was used to assess the clinical characteristics of the ASD group. RESULTS: vmHRV measures (root mean square of successive RR intervals [RMSSD], percentage of successive RR intervals that differ by more than 50 ms [pNN50], and high-frequnecy power) did not differ between the ASD and TD groups. By contrast, the beta1 coherence between the T5 and T6 electrodes (beta1 coherence [T5-T6]) was lower in the ASD group than in the TD group, even after correction for multiple comparisons. This coherence measure demonstrated a positive correlation with RMSSD and a negative correlation with the SRS social motivation subscale score (SRS-Motivation). Moreover, pNN50 acted as a moderator of the association between beta1 coherence (T5-T6) and SRS-Motivation. CONCLUSION: Resting-state EEG coherence may be associated with the clinical characteristics of ASD, and vmHRV may exert a moderating effect on this relationship. These preliminary findings suggest that the concurrent evaluation of brain and autonomic functions can be useful for elucidating the pathophysiology of ASD.