Psychophysiological characteristics of the regulatory disordered infant
This study examined the psychophysiological responses to sensory and cognitive challenges of 24 normal and 11 regulatory disordered infants (8–11 months). Regulatory disordered infants were defined as being behaviorally difficult and exhibiting disturbances in sleep, feeding, state control, self-calming, and mood regulation. Heart period and cardiac vagal tone were measured during baseline and during sensory and cognitive challenges. The regulatory disordered infants tended to have higher baseline vagal tone. Across groups there was a significant suppression of vagal tone during cognitive processing. Baseline vagal tone was correlated with the suppression of vagal tone during the cognitive task only for the normal infants. In contrast, the responses of the infants with regulatory disorders were heterogeneous. The results provide preliminary support for the hypothesized relationship between vagal tone and the regulatory disorder.