[Influence of post-conceptual age on the electromyographic characteristics in the newborns]

The purpose of the study was to investigate neuromuscular status in the preterm infants using surface electromyography (EMG). 10 preterm (gestational age 31/32 weeks) and 10 term infants (gestational age 38/39 weeks) participated in the study on the 2nd, 4th and 6th postnatal week. Linear and novel non-linear parameters of were used to quantitize interference EMG (iEMG) in 4 muscles (mm. bic. br. dext., tric. br. dext, tib. ant. sin., gastr. sin. In the preterm infants aged 33-37 weeks both linear and non-linear sEMG parameters were significantly lower in comparison with the term infants. Thus, sEMG of the preterm infants was characterized by a more "primitive" time-domain structure, lower amplitude and spectrum frequency. Also, unlike to term newborns, in the preterm infants the lifetime dynamics ofsEMG parameters was retarded. Thus, the motor system of the preterm infant is likely less prepared to the postnatal life due to shorter existence in utero. Nonetheless, sEMG of the preterm infants may be characterized as a more "complex" in comparison with the term newborns of the same post-conceptual age. It may be attributed to new postnatal sensory stimuli.