Visual and somatosensory contributions to infant sitting postural control

Abstract

There are a limited number of studies that have investigated sitting posture during infancy and the contribution of the sensory systems. The goal of this study was to examine the effects of altered visual and somatosensory signals on infant sitting postural control. Thirteen infants (mean age ± SD, 259.69 ± 16.88 days) participated in the study. Initially, a single physical therapist performed the Peabody Developmental Motor Scale to determine typical motor development. Then the child was placed onto a force platform under four randomized conditions: (a) Control (C) – sat independently on the force plate, (b) Somatosensory (SS) – Sat independently on a foam pad (low density), (c) Visual (VS) – sat independently on the force plate while the lights were turned off creating dim lighting, and (d) Combination of b and c (NVSS). Center of pressure (COP) data from both the anterior-posterior (AP) and the medial-lateral (ML) directions were acquired through the Vicon software at 240 Hz. The lights off conditions, both VS and NVSS, lead to increased Root Mean Square (RMS) and Range values in the AP direction, as well as increased Lyapunov Exponent (LyE) values in the ML direction. Altered visual information lead to greater disturbances of sitting postural control in typically developing infants than altered somatosensory information. The lights off conditions (VS and NVSS), unveiled different control mechanisms for AP and ML direction during sitting. Thus, the present findings confirm the dominance of vision during the early acquisition of a new postural accomplishment.

Keywords:

• Motor development
• center of pressure
• sensory

Acknowledgements

We would like to thank all the infants and their families for participation in this study as well as Dr. Regina Harbourne for helping with many data collections and performing the Peabody test. We would also like to thank Dr. Joan Deffeyes for providing the matlab code for the analysis of the data as well as Dr. Kris Berg for providing critical comments and edits on a previous draft of the manuscript.

Disclosure statement

Anastasia Kyvelidou declares no conflict of interest. Nick Stergiou receives royalties from Human Kinetics and CRC Press.

Additional information

Funding

This study was supported by Bukey and MacDonald Fellowship to Dr. Anastasia Kyvelidou from the University of Nebraska Medical Center. Dr. Nick Stergiou is currently supported by NIH P20GM109090 and NIH R15HD08682.