Reliability and Validity of the GWalk for Use in Postural Control

Introduction: Clinical examinations are highly subjective when compared to the more sensitive and robust measures observed with force platform assessment. Currently, few methods exist to quantify objective postural control deficits in an easier and more accessible way for clinicians. Purpose: The purpose of this study was to examine the reliability and validity of a wireless inertial sensing device, the BTS GWalk, during postural control assessment. Methods: Fifty-six participants (27 male, 22 ± 1.9 years, 29 female, 21 ± 0.9 years) performed three trials each of quiet standing with eyes open (EO) and eyes closed (EC) on a force platform (FP). Participants were fitted with the BTS GWalk, which was placed on the lower back. To establish reliability, trials were administered over two time points approximately 48-72 hours apart. Raw center of pressure (COP) data from the FP and GWalk were exported and further analyzed using Excursion (ExcML/ExcAP) in the mediolateral and anteroposterior directions. Reliability of both devices was determined using a repeated measures ANOVA and corresponding ICC values. Criterion validity was determined using Pearson’s correlations in SPSS v 23.0 Results: Repeated measures ANOVAs showed no significance for time or device. In the EO condition, the GWalk demonstrated excellent reliability in the ExcML (ICC=.929) and ExcAP (ICC=.791) directions. In the EC condition, the GWalk showed excellent reliability in ExcML and AP (ICC=.909, .781). However, the repeated measures ANOVA showed significant differences for device (p ML (EO r= .703, EC r= .703), ExcAP (EO r= .732, EC r= .736). Discussion: Results of the current study indicate the GWalk is a reliable and moderately valid measurement of postural control in healthy populations, but currently is not recommended for comparison against COP parameters. Further research should examine the use of the GWalk against a measure of center of mass, to potentially provide an objective postural control assessment in clinical settings