Normative database of postural sway measures using inertial sensors in typically developing children and young adults

Objective: Reference values utilizing the APDM MobilityLab® inertial sensor system have not been established in children and young adults ages 5-30. These values are necessary for clinicians and researchers to compare to children with balance impairments.

Methods: A group of 144 typically developing children and young adults from age 5-30 years completed the instrumented SWAY test during 6 test conditions: normal stance, firm surface, eyes open (EO) and closed (EC); normal stance, foam surface, EO and EC; and tandem stance, firm surface, EO and EC. Selected variables for normative outcomes included total sway area, and the mean, sagittal and coronal values for RMS sway, jerk, sway velocity and path length. Sex differences were examined within age groups via t tests. The effect of age on postural sway variables was analyzed using a one-way ANOVA for the mean values of total sway area, RMS sway, velocity and jerk, followed by post-hoc pairwise comparisons.

Results: All sway parameters decreased significantly with age (p < 0.0001). Adult-like total sway area and jerk were achieved by ages 9-10 except for jerk during EC on foam. RMS sway and sway velocity reached adult levels by ages 11-13 during all EO and tandem stance conditions, and 14-21 with EC during normal stance on firm and foam surfaces for RMS sway and EC on firm surfaces for velocity. Females ages 5-6 performed more poorly during EO firm and EC foam for certain variables, but better during EO tandem and females ages 7-13 outperformed males when sex differences were found.

Significance: These reference values can now be used by clinicians and researchers to evaluate abnormal postural sway and response to interventions in children and young adults.