Test-Retest Reliability of Selected NeuroComŽ Postural Stability Assessments

Background/Purpose: Sports-related mild traumatic brain injury (MTBI), or concussion, is a growing public health dilemma (CDC, 2014). There is controversy regarding how to accurately diagnose and gauge severity of MTBI. Previous studies found that postural stability, balance, is a stable indicator, and is one of three major categories included with the commonly-used, globally-accepted SCAT3 sideline assessment (McCrory et al., 2013). One computerized balance system, NeuroCom® VSR™ Sport, uses force plate technology that measures an athlete’s balance while attempting tasks. Baselines are compared to post injury measures to guide medical experts to diagnose and treat concussed athletes. Purpose for this study was to assess reliability for NeuroCom® VSR™ Sport measures; three Stability Evaluation Tests (SET), identical to SCAT3 tests, and four Limits of Stability (LOS) tests with student athletes.

Method: Participants (n=139) included high school (n=82) and collegiate (n=57) student athletes (male≈45%; female≈55%). All were tested twice (pre-season/post-season) using the same NeuroCom® VSR™ Sport system. Measuring subjects’ time data (TD) and sway velocity (SV) with eyes closed, hands on hips for 20 seconds with three SET tests (excluded foam pad), the double (feet horizontally placed, touching side by side), single (non-dominant foot only), and tandem (both feet together/touching, vertically placed) balance tests. The four LOS tests involved assessing how each subject’s voluntary motor system could efficiently move his/her center of gravity forward, to the right, back, and left, measuring the five variables of reaction time (RT); end point percentage (EPE); maximum excursion percentage (MXE); movement velocity (MVL); and directional control (DCL).

Analysis/Results: Test-retest reliability results for SET and LOS measures indicated low to moderate reliability. The SET reliability coefficients measuring TD and SV ranged from .160 to .398 for single and tandem. The double test SV was relatively high (r=.621), and all subjects completed the double 20 second task both pre-and post. Reliability scores for the four LOS tests of forward, backward, right, and left (in order) using test variables were:  RT= .386, .114, .344, and .326; EPE= .277, .168, .226, and .088; MXE= .381, .127, .068, and .158; MVL= .096, .203, .513, and .501; and DCL= .315, .331, .438, and .448.

Conclusions: Using measures with low to moderate reliability to diagnose concussion is ill-advised. This research found NeuroCom® balance protocols among high school and college student athletes achieved low to moderate reliability. Further research to revise noted tests and to develop more accurate protocols to identify MTBI is needed.