Early oral behaviour in preterm infants during breastfeeding: an electromyographic study

The objectives were to increase the understanding of the characteristics of oral behaviour during breastfeeding in preterm infants and to validate dir ect observations of infant sucking. Twenty-six infants were investigated on ce by simultaneous observation and surface electromyography (EMG) at 32.1-3 7.1 postmenstrual weeks. The orbicularis oris muscle was used for data anal ysis, as it provided the most distinct registrations. High correlation coef ficients were observed with respect to classifications of EMG data by two r aters on the number of sucks per burst (r = 0.97) and duration of sucking b ursts (r = 0.99). The agreement between direct observations of sucking and EMG data was high. The median for mean number of sucks per burst was 8 (ran ge 2-33) and for longest burst 28 (5-96) sucks. Sucks with low and very hig h intensity constituted a median of 14 (1-94)% and 25 (0-87)% of all sucks. The range in mean sucking frequency was 1.0-1.8 sucks s(-1). Suck duration ranged from 0.6 to 1.1 s. There was a considerable variation between infan ts in the extent of mouthing. No association with maturational level appear ed for any of the components in oral behaviour. Conclusion: EMG data provided evidence of early sucking competence in prete rm infants during breastfeeding, with wide individual variations. Surface E MG and direct observation are recommended as valid methods in the evaluatio n of breastfeeding behaviour in preterm infants.