Article

The purpose of this study was to
determine whether infants born preterm and infants born at full term differed in
postural control at 1 to 3 weeks after term age. DESIGN:
This study included 17
infants born preterm (mean gestational age=31.9 weeks, range=25.0-34.6) and 15
infants born at full term (mean gestational age=38.9 weeks, range=37.3-40.6). All
infants were without diagnosed neurological or genetic conditions. MEASUREMENT:
Center-of-pressure (COP) data were recorded at 5 Hz while each infant was
positioned supine on a pressure-sensitive mat in an alert behavioral state. Root
mean square (RMS) displacement and approximate entropy (ApEn) were used to
describe the COP movement variability in the time series. Differences between
groups were identified using independent t tests. RESULTS: The COP time series
were found to be deterministic, suggesting order in the time series. Infants born
preterm exhibited significantly larger RMS values in the caudal-cephalic
direction than infants born at full term (1.11 and 0.83 cm, respectively; t=-2.6,
df=30, P=.01). However, infants born at full term had significantly larger ApEn
values in the caudal-cephalic direction (1.19 and 1.11, respectively; t=2.4,
df=30, P=.02). The 2 groups did not differ in RMS or ApEn values in the
medial-lateral direction or the resultant. CONCLUSIONS:
Infants born at full term
exhibited COP displacements in the caudal-cephalic direction that were smaller in
amplitude, but may be considered more complex or less predictable, than those of
infants born preterm. One explanation is that infants born preterm exhibited more
stereotypic patterns of movement, resulting in large, but repetitive, COP
excursions. A combination of linear and nonlinear measures may provide insight
into the control of posture of young infants.

Langue : ANGLAIS