Associations between General Movements Assessment and Postural Control in Preterm and Full-term Infants during Early Infancy

This study aimed to compare postural control between preterm and full-term infants and to investigate the associations between postural control and GMA in preterm and full-term infants around 4 months corrected age.

Full-term and preterm infants were recruited for assessing postural control and GMA. Postural control was examined using a pressure plate (FDM-S, Zebris) to collect infants’ center-of-pressure (COP) trajectories for 5 minutes while lying supine and allowing free spontaneous movements. At the same time, infants’ spontaneous movements were filmed for later GMA. The root mean square (RMS), approximate entropy (ApEn), and multiscale entropy (MSE) of COP trajectories in both the cephalocaudal (cc) and mediolateral (ml) directions were calculated for further analysis. One GMA-certified investigator examined the videos and determined infants’ spontaneous movements were normal or abnormal. Group differences were assessed using independent t-tests or Mann-Whitney U tests. Associations between GMA results and postural control parameters were examined using logistic regression and Spearman correlation. Statistical significance was set at p.05.

Fifteen full-term (gestational age: 39 weeks) and 14 preterm infants (gestational age: 31 weeks) were enrolled. All full-term infants were normal on GMA and 4 preterm infants were abnormal on GMA. Both preterm and full-term infants were comparable in RMS-cc and RMS-ml of COP trajectories. Compared to full-term infants, preterm infants revealed significantly lower ApEn-ml, MSE-cc (scale 2 to 20), and MSE-ml (scale 1 to 20) of COP trajectories. Furthermore, infants with abnormal GMA results had significantly lower ApEn-ml, MSE-cc (scale 1) than those with normal GMA results. Analysis of the relationships between GAM results and postural control parameters revealed that only ApEn-ml of COP trajectories was significantly associated with GMA results while RMS-cc, RMS-ml, and ApEn-cc of COP trajectories were not.

During early infancy, preterm infants and those infants with abnormal GMA results exhibited less complex postural control patterns, particularly in mediolateral direction.

Findings of this study suggest that assessment of postural control during early infancy may provide clues for designing early intervention programs for infants who exhibit less variable COP trajectories.