Reduction in limb-movement complexity at term-equivalent age is associated with motor developmental delay in very preterm or very low birth weight infants

Abstract

Abstract Background: Reduced complexity during the writhing period can be a crucial characteristic of spontaneous movements in infants at high-risk for neurologic impairment. The aim of this study was to verify the association between quantified complexity of the upper- and lower-limb movements at term-equivalent age and motor development in very preterm or very low birth weight infants. Methods: Video images of spontaneous movements at term-equivalent age and clinical data were collected prospectively from very preterm or very low birth weight infants in this study. A pretrained pose-estimation model and sample entropy (SE) were employed to extract positional coordinates and quantify the complexity of the upper- and lower-limb movements. The motor development of infants was evaluated at 9 months of corrected age using Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III). The SE measures of the upper and lower limbs were compared between infants with and without motor developmental delay (MDD). Results: Among a total of 90 consecutive infants, there were 11 infants with MDD. SE values for most of the upper and lower limbs during spontaneous movement were significantly reduced in infants with MDD compared to those without MDD (p<0.05). The composite scores for the motor domain of BSID-III showed significant positive correlations with SE values in most upper and lower limbs during spontaneous movements (p<0.05). Conclusions: This study demonstrated that the complexity of limb movements in very preterm or very low birth weight infants at term-equivalent age was reduced in infants with MDD at 9 months of corrected age. SE of limb movements can be a potentially useful kinematic parameter to detect high-risk infants for MDD.