Vestibular function assessment using the NIH Toolbox

Abstract

Objective: Development of an easy to administer, low-cost test of vestibular function.

Methods: Members of the NIH Toolbox Sensory Domain Vestibular, Vision, and Motor subdomain teams collaborated to identify 2 tests: 1) Dynamic Visual Acuity (DVA), and 2) the Balance Accelerometry Measure (BAM). Extensive work was completed to identify and develop appropriate software and hardware. More than 300 subjects between the ages of 3 and 85 years, with and without vestibular dysfunction, were recruited and tested. Currently accepted gold standard measures of static visual acuity, vestibular function, dynamic visual acuity, and balance were performed to determine validity. Repeat testing was performed to examine reliability.

Results: The DVA and BAM tests are affordable and appropriate for use for individuals 3 through 85 years of age. The DVA had fair to good reliability (0.41-0.94) and sensitivity and specificity (50%-73%), depending on age and optotype chosen. The BAM test was moderately correlated with center of pressure (r = 0.42-0.48) and dynamic posturography (r = -0.48), depending on age and test condition. Both tests differentiated those with and without vestibular impairment and the young from the old. Each test was reliable.

Conclusion: The newly created DVA test provides a valid measure of visual acuity with the head still and moving quickly. The novel BAM is a valid measure of balance. Both tests are sensitive to age-related changes and are able to screen for impairment of the vestibular system.

Figure 1. Rate sensor attached to headband and hat for monitoring rate of head movement

Figure 2. Accelerometer attached to gait belt and placed anteriorly on adults (A), posteriorly on children (B)

Figure 3. Age effects from Balance Accelerometry Measure condition 4. Scores were optimal between 18 and 35 years of age