Document Type

Article

Publication Date

8-2009

Abstract

Background

Upright sitting is one of the first developmental motor milestones achieved by infants, and sitting postural sway provides a window into the developing motor control system. A variety of posture sway measures can be used, but the optimal measures for infant development have not been identified.

Methods

We have collected sitting postural sway data from two groups of infants, one with typical development (n = 33), and one with delayed development and either diagnosed with or at risk for cerebral palsy (n = 26), when the infants had developed to the point where they could just maintain sitting for about 10 s. Postural sway data was collected while infants were sitting on a force platform, and the center of pressure was analyzed using both linear and nonlinear measures.

Findings

Our results showed that a nonlinear measure, the largest Lyapunov exponent, was the only parameter of postural sway that revealed significant differences between infants with typical versus delayed development. The largest Lyapunov exponent was found to be higher for typically developing infants, indicating less repeated patterning in their movement coordination.

Interpretations

A nonlinear measure such as largest Lyapunov exponent may be useful as an identifier of pathology and as a yardstick for the success of therapeutic interventions.

Comments

NOTICE: this is the author’s version of a work that was accepted for publication in Clinical Biomechanics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Clinical Biomechanics, Vol. 24, Issue 7 (August 2009) DOI: doi:10.1016/j.clinbiomech.2009.05.004.

Journal Title

Clinical Biomechanics

Volume

24

Issue

7

First Page

564

Last Page

570

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Biomechanics Commons

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