Three physiological responses in fathers and non-fathers' to vocalizations of typically developing infants and infants with Autism Spectrum Disorder.

Children with ASD, even before receiving a formal diagnosis, express atypical patterns of distress vocalizations (namely, episodes of crying). Their cries have higher fundamental frequencies, shorter inter-bout pauses, and fewer utterances. Cries of children with ASD are also perceived differently from other cries, and these perceptual differences may alter parent-infant interaction. This study assessed multiple physiological responses in fathers and non-fathers to atypical distress vocalizations (cries of children with ASD), acoustically matched typical distress vocalizations (cries of typically developing children), and positive vocalizations (laughter of typically developing children). The experimental procedures were designed to measure how components of the autonomic nervous system respond to typical and atypical infant vocalizations. Three convergent methodologies (Galvanic Skin Response-GSR; cardiac dynamics via Inter-Beat Interval-IBI; right hand temperature change-RHTC) were performed on two groups with contrasting caregiving experience: fathers of typically developing children (n=10) and non-fathers (n=10). Inferential statistical analysis compared the two groups (fathers, non-fathers) and three stimulus types (ASD cry, typical cry, laughter) for the three measures (GSR, IBI, RHTC). Both fathers and non-fathers showed greater negative responses (increased GSR) to ASD cries compared to typical cries and laughter. Fathers showed higher IBI and greater temperature increases (RHTC) than non-fathers while listening to typical and atypical cries. Fathers and non-fathers showed more emotional arousal mediated by sympathetic activation while listening to cries of children with ASD. Fathers were calmer and acted more promptly than non-fathers while listening to typical cries, perhaps because the fathers had more experience in caring for crying infants. These findings point to similarities and differences in fathers' and non-fathers' physiological responsiveness to cries of children with ASD and might guide specific intervention programs for parents of children at risk of ASD.