Introduction The presence and extent of decoupling, ie, the absence of simultaneous alterations of fundamental frequency and intensive intensity contour during crying, reflects maturation of the central nervous system. Data on maturational aspects of decoupling are limited.
Methods To assess decoupling in healthy term neonates, crying during venous blood sampling (Guthrie test) was recorded up to 3 minutes afterwards. Using a 512 sample Hamming window, the fundamental frequency and intensity contour was extracted. The degree of decoupling was quantified by calculating the correlation coefficient between both crying characteristics (fundamental frequency, intensity contour). Decoupling was defined as a correlation coefficient <0.5).
Results Based on 1157 cry bouts in 47 healthy term neonates collected, decoupling was observed in 21%. However, the average correlation coefficient calculated over all the cries recorded during the 3-minute test varied between 0.2 and 0.95, with extensive inter and intra-subject variability.
Conclusions The present observations indicate that decoupling can already be observed in term neonates. The degree of decoupling displays extensive inter and intra-subject variability. Crying analysis is non-invasive and the current methodology implies quantitative data on the degree of coupling. It hereby opens up the possibility to describe cry complexity and its covariates further.