Regulation of sinus cardiac rhythm during different states of attention in full-term and preterm 5-month-old infants

Abstract

Parasympathetic heart rate regulation was studied in full-term (FT) and very preterm (VPT) infants at the corrected age of 5 months during endogenous and exogenous sustained attention. Cardiac interval duration and the respiratory sinus arrhythmia (RSA) were used as indices of parasympathetic regulation of heart activity during infants’ sustained attention to a new visual stimulus (exogenous attention) and anticipatory attention to repeatedly appearing and disappearing stimuli in the visual expectation paradigm (endogenous attention). The psychomotor development and behavior regulation were assessed using the Bayley Scales of Infant Development, and the clinical risk was scored on the Ballard scale. A shift of attention state affected the RSA only in the FT infants. The endogenous attention was associated with a relatively high RSA level, with the higher RSA levels being significantly correlated with the Bayley Behavior Rating Scale scores. At the age of 5 months, the degree of clinical risk in the VPT infants was not correlated with specific features of parasympathetic regulation. The results are discussed in terms of the concepts of physiological mechanisms of exogenous and endogenous attention in infants. The central regulation of the autonomic functions during a shift of attention state is less efficient in healthy VPT infants as compared to their FT peers. The RSA reactivity can be a more sensitive indicator of CNS regulatory disorders than the standard indices of clinical risk.