The differences noted in sympathovagal balance may be affected by the differences in clinical diagnosis, especially the presence of syndromes related to the IESS group (e.g., SCN2A, tuberous sclerosis, Ohtahara syndrome, and polymicrogyria) compared to the control group and/or different maturity of the ANS and sleep patterns of 2 months old. Here, SCN2A is linked to infantile spasms.