Coordination of head and trunk in sitting position of preterm and full-term infants
Date Issued
2016
Date
2016
Author(s)
Liu, Yan-Ling
Abstract
Children born preterm are at risk for postural deficits and motor disabilities. To achieve successful postural control, one needs to manage the many degrees of freedom of the human body in the gravitational and sensory world. However, little is known about how infants develop to control the multi-segmented body in the upright posture and how such coordination of postural control may be affected by preterm birth. The purpose of this study was to investigate the upper body coordination in sitting posture of full-term and preterm infants and to examine the influence of additional somatosensory information on infants’ postural coordination. Three groups of infants were included in the study: early preterm (Pte, gestational age <34 weeks, n=12), late preterm (Ptl, gestational age≧34 weeks and <37 weeks, n=15), and full-term (Ft, n=12). Infants were longitudinally followed from sitting onset to 3months post-walking at 7 developmental epochs: sitting onset, 1- month post sitting, 2- month post sitting, standing alone, walking onset, 1-, and 3- month post walking. At each visit, the infant was tested for their quiet sitting posture in two sensory conditions: with or without the hand touching a contact surface. Three- dimensional displacements of the head and trunk were recorded using an ultrasonic motion capture system. Cross-correlation analyses were conducted to analyze the spatial and temporal coordination between head and trunk motions in the medial-lateral (ML) and anterior-posterior (AP) directions. Repeated measures ANOVAs were conducted to examine effects of postural experience, hand touch, and preterm birth on infants’ upper body coordination in sitting position. Our results revealed that, comparing to sitting onset, the spatial coupling between infants’ head and trunk decreased after 1 month post sitting and onward in the AP direction. For the ML direction, the un-coupled coordination occurred only at 2 months post-sitting (p<0.05). Comparing to sitting onset, the absolute time lag between head and trunk decreased at standing alone in the ML direction (p<0.05) but no difference between developmental epochs was found in the AP direction. Hand touch decreased the spatial coupling between head and trunk only in the ML direction (p<0.05). Pte, but not Ptl, infants demonstrated lower spatial and temporal head-trunk coupling in the ML direction compared to Ft infants (p<0.05). Our results suggest that, with increasing upright experience, infants’ upper body coordination in sitting posture changed from synchronous patterns toward articulated patterns. While early development of sitting postural control occurred more obvious in the AP direction than in ML direction, hand touch afforded infants to explore dynamics of body coordination in the ML direction. Furthermore, early preterm infants exhibited more mature patterns of body coordination than full-term infants did in controlling their sitting posture. Due to the small sample size and relatively healthy preterm sample, our results may not apply to all preterm infants. Our results that early development of sitting postural control occurs mostly in the AP direction and can be influenced by sensory inputs may help design intervention programs for infants and children with postural deficits. Long-term follow up of early and late preterm infants for their postural control and body coordination is necessary.
Subjects
Posture
Coordination
Sitting
Preterm
Infant
SDGs
Type
thesis