Journal of PHYSIOLOGICAL ANTHROPOLOGY
Online ISSN : 1880-6805
Print ISSN : 1880-6791
ORIGINALS
A Dynamical System Analysis of the Development of Spontaneous Lower Extremity Movements in Newborn and Young Infants
Hirotaka GimaShohei OhgiSatoru MoritaHiroshi KarasunoTakayuki FujiwaraKoji Abe
Author information
JOURNAL FREE ACCESS

2011 Volume 30 Issue 5 Pages 179-186

Details
Abstract

This study's aim was to evaluate the characteristics of newborn and young infants' spontaneous lower extremity movements by using dynamical systems analysis. Participants were 8 healthy full-term newborn infants (3 boys, 5 girls, mean birth weight and gestational age were 3070.6 g and 39 weeks). A tri-axial accelerometer measured limb movement acceleration in 3-dimensional space. Movement acceleration signals were recorded during 200 s from just below the ankle when the infant was in an active alert state and lying supine (sampling rate 200 Hz). Data were analyzed linearly and nonlinearly. As a result, the optimal embedding dimension showed more than 5 at all times. Time dependent changes started at 6 or 7, and over the next four months decreased to 5 and from 6 months old, increased. The maximal Lyapnov exponent was positive for all segments. The mutual information is at its greatest range at 0 months. Between 3 and 4 months the range in results is narrowest and lowest in value. The mean coefficient of correlation for the x-axis component was negative and y-axis component changed to a positive value between 1 month old and 4 months old. Nonlinear time series analysis suggested that newborn and young infants' spontaneous lower extremity movements are characterized by a nonlinear chaotic dynamics with 5 to 7 embedding dimensions. Developmental changes of an optimal embedding dimension showed a U-shaped phenomenon. In addition, the maximal Lyapnov exponents were positive for all segments (0.79–2.99). Infants' spontaneous movement involves chaotic dynamic systems that are capable of generating voluntary skill movements.

Information related to the author
© 2011 Japan Society of Physiological Anthropology
Next article
feedback
Top