Effect of the kangaroo position on the electromyographic activity of preterm children: a follow-up study

One of the components of the Kangaroo Method (KM) is the adoption of the Kangaroo Position. The skin-to-skin contact and the vertical position the child adopts when in this position may provide sensorial, vestibular and postural stimuli for the newborn. The Kangaroo Position may encourage vestibular stimuli and a flexed posture of the limbs, suggesting the hypothesis that the Kangaroo Position may have an impact on flexor muscle tone. The effect of these stimuli on the motor features of the newborn has not been the subject of much investigation. No study has yet been conducted to determine whether the Kangaroo Position may progressively increase electromyographic activity or whether this increase persists until term-equivalent age. The aim of this study was to evaluate the effect of the Kangaroo Position on the electromyographic activity of preterm children.

A follow-up study was carried out between July and November 2011 at the Instituto de Medicina Integral Prof. Fernando Figueira (IMIP), Recife-Brazil, using a sample of 30 preterm children. Surface Eletromyography (SEMG) was used to investigate the muscle activity of biceps brachii. The electromyographic readings were taken immediately before (0 h) and after 24 h, 48 h, 72 h, 96 h of application of the Kangaroo Position as well as at the term equivalent age in each baby. Electromyographic activity was analyzed using the Root Mean Square (RMS) and the mean values of the times were analyzed by way of analysis of variance for repeated measures and the Tukey test.

Electromyographic activity of the biceps brachii varied and increased over the whole 96h period (RMS:0 h = 36.5 and 96 h = 52.9) (F(5.174) = 27.56; p < 0.001) and remained constant thereafter (RMS: term-equivalent age = 54.2). The correlations between the corrected age and the values for electromyographic activity did not show any statistical significance.

The Kangaroo Position leads to a growing increase in the electromyographic activity of preterm children’s biceps brachii after up to 96 h of stimulation and this response persists until at least the 21st day after this period.