Validity of Postural Sway Assessment on the Biodex BioSway™ Compared With the NeuroCom Smart Equitest.

CONTEXT: Current tools for sideline assessment of balance following a concussion may not be sufficiently sensitive to identify impairments, which may place athletes at risk for future injury. Quantitative field-expedient balance assessments are becoming increasingly accessible in sports medicine and may improve sensitivity to enable clinicians to more readily detect these subtle deficits.

OBJECTIVE

To determine the validity of the postural sway assessment on the Biodex BioSway™ compared with the gold standard NeuroCom Smart Equitest System.

DESIGN

Cross-sectional cohort study.

SETTING

Clinical research laboratory.

PARTICIPANTS

Forty-nine healthy adults (29 females: 24.34 [2.45] y, height 163.65 [7.57] cm, mass 63.64 [7.94] kg; 20 males: 26.00 [3.70] y, height 180.11 [7.16] cm, mass 82.97 [12.78] kg).

INTERVENTION(S): The participants completed the modified clinical test of sensory interaction in balance on the Biodex BioSway™ with 2 additional conditions (head shake and firm surface; head shake and foam surface) and the Sensory Organization Test and Head Shake Sensory Organization Test on the NeuroCom Smart Equitest.

MAIN OUTCOME MEASURES: Interclass correlation coefficient and Bland-Altman limits of agreement for Sway Index, equilibrium ratio, and area of 95% confidence ellipse.

RESULTS

Fair-good reliability (interclass correlation coefficient = .48-.65) was demonstrated for the stance conditions with eyes open on a firm surface. The Head Shake Sensory Interaction and Balance Test condition on a firm surface resulted in fair reliability (interclass correlation coefficient = .50-.59). The authors observed large ranges for limits of agreement across outcome measures, indicating that the systems should not be used interchangeably.

CONCLUSIONS

The authors observed fair reliability between BioSway™ and NeuroCom, with better agreement between systems with the assessment of postural sway on firm/static surfaces. However, the agreement of these systems may improve by incorporating methods that mitigate the floor effect in an athletic population (eg, including a head shake condition). BioSway™ may provide a surrogate field-expedient measurement tool.