Objective Prior research has suggested deficits in sensorimotor integration during balance; however, multisensory integration (i.e., the ability to combine information from multiple sensory systems) has not been studied in isolation. The Subjective Visual Vertical (SVV) tests a person’s ability to integrate visual and vestibular information in relation to perceived vertical. The objective of this study was to determine test-retest reliability of the SVV in healthy, young adults, and to determine changes in SVV following concussion. We hypothesized SVV test-retest reliability would be ICC > .75 and that SVV performance would be worse following concussion.

Design Observational

Setting Research laboratory

Participants Ten healthy, young adults (five women, age = 24.7±6.4 years) and four participants (two women, age = 22.5±3.8 years) within 13.7±1.9 days post-concussion and still symptomatic completed SVV testing in a virtual reality head-mounted display (Neurolign, Dx-100, Pittsburgh, PA) sub-acutely and at time of return to activity.

Outcome Measures We used intraclass correlation coefficients to determine test-retest reliability of the mean error. We used univariate regression to determine the effect of group, time, and the group-by-time interaction.

Main Results Test-retest reliability across approximately seven weeks was 0.638, indicating moderate reliability. There was no group-by-time interaction (F_1,23=.840, p=.369, η_p ² =.035). However, concussion participants (mean absolute value=3.16) performed worse than control participants (mean absolute value=2.00; F_1,23=3.064, p=.093, η_p ² =.118) across both time points. Both groups worsened over time (sub-acute=1.76; subacute=2.88; F_1,23=4.135, p=.054, η_p ² =.152).

Conclusions Although preliminary in nature, findings represent large effect sizes, suggesting potentially clinically important differences in visual-vestibular integration.