A dynamical system analysis of the development of spontaneous lower extremity movements in newborn and young infants.
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.
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ABSTRACT: Complex rhythms are observed in the physiological systems that control and carry out vital bodily functions. Theoretical approaches to analyze the physiological systems include control theory and computation theory. Complementary to these approaches is nonlinear dynamics, which offers ways to classify both normal and abnormal dynamics, and to analyze bifurcations occurring in physiological dynamics.Chaos (Woodbury, N.Y.) 11/1991; 1(3):247-250. · 1.80 Impact Factor
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ABSTRACT: Background. Studies have reported that infants with hemiplegia of congenital origin may have a period between birth and up to 12 months when clinical signs of hemiplegia are not evident. The aim of this study was to establish whether the assessment of general movements (GMs) may help in the earlier detection of signs of hemiplegia. Subjects and Methods. Eleven infants with cerebral infarction on brain MRI, and eleven normal controls were enrolled in the study. Quality of GMs was assessed from videotapes between 3 and 6 weeks and between 9 and 16 weeks. Neurological outcome was evaluated at least at two years. Results. Seven of the 11 infants had an assessment performed between 3 and 6 weeks: abnormal GMs were observed in all the infants who developed hemiplegia, but one child had abnormal GMs and a normal outcome. All 11 infants had a scorable assessment between 9 and 16 weeks. In all a specific type of GMs, fidgety movements (FMs), were predictive of neurological outcome. The presence of early asymmetries at both 3 - 6 and 9 - 16 weeks was also significantly associated with later signs of hemiplegia. Conclusions. The assessment of GMs after the neonatal period appears to be very useful in the early identification of hemiplegia in infants with cerebral infarction. Whilst the prediction of hemiplegia should be possible from early neonatal MRI brain scans, this facility is not always available. Observation of GMs is a bedside clinical approach that allows confirmation of early prediction from MRI, early rehabilitation if needed and reassurance that neurological outcome will be good where that is appropriate.Neuropediatrics 05/2003; 34(2):61-6. · 1.19 Impact Factor