Subjective assessment of visual verticality in follow-up of patients with acute vestibular disease.

We conducted a study of 10 patients with acute unilateral peripheral vestibular failure in order to assess their ability to perceive visual verticality during the acute stage of their disease and during recovery. We also evaluated 31 healthy volunteers to test the reproducibility of our assessment methods. The 10 patients were first evaluated within 4 days of the onset of their vestibular failure, and follow-up tests were conducted 2 and 4 weeks later. The healthy subjects were similarly tested at 2 and 4 weeks following their baseline evaluation. All patients and subjects were tested 10 times during each evaluation session, and results from each as well as from the groups as a whole were calculated as a mean of all responses. The mean visual vertical tilt (the amount of deviation from true verticality) among the 10 patients declined from 8.4 degrees (+/- 2.4 degrees) at the first examination to 3.2 degrees (+/- 1.6 degrees) at week 2 and to 1.4 degrees (+/- 0.7 degree) at week 4. These decreases coincided with the pace of the resolution of their vestibular symptoms. The rates of reproducibility among the 31 healthy volunteers at 2 and 4 weeks following their initial assessment were 95 and 97%, respectively. We concluded that repeated measurements of the static visual vertical can be useful as a follow-up tool for patients with vestibular neuritis.