Dynamic visual acuity during head-thrust test in canal planes in healthy subjects and patients with vestibular neuritis.

CONCLUSIONS

Dynamic visual acuity (DVA) during the head-thrust test (htDVA) is reliable in normal subjects, having a high specificity for the horizontal canal, so it may be useful to monitor vestibular rehabilitation in patients with vestibular neuritis (VN).

OBJECTIVE

To obtain reference values for htDVA in healthy individuals and to investigate the potential application in subjects with unilateral VN.

METHODS

A total of 73 healthy individuals and 50 patients with unilateral VN were included. The DVA test was performed by adjusting a sensor on the subject's head to measure head velocity. During head thrust, the optotype flashed if the head velocity reached 150°/s, as previously defined, and a DVA score was obtained for each canal.

RESULTS

The htDVA was reliable in normal subjects (intra-class correlation coefficient (ICC) = 0.44-0.71; p = 0.001-0.007). The htDVA score showed an age-dependent increase for all canals (p < 0.0001). The 95th percentile of htDVA was used as the criterion to consider htDVA as abnormal in patients with VN. In all, 44%, 30%, and 16% of patients had an increase in htDVA score for one, two or all three canals on the affected side. The sensitivity and specificity of the htDVA test for the horizontal canal were 22% and 85%, respectively.