Repeatability of static posturography on the follow-up of vestibular rehabilitation

We undertook this study to estimate the limits of agreement of repeated measures of static posturography on healthy adults and to assess the use of those limits on the interpretation of variations observed during vestibular rehabilitation of patients with chronic, peripheral vestibular disease.

Twenty healthy adults and 30 vestibular patients accepted to participate. At baseline and at weeks 4, 6 and 8 of follow-up, posturography was performed with the eyes open or closed, while adding or not a layer of foam rubber to the base of support. The Dizziness Handicap Inventory was administered to patients prior to rehabilitation and at week 8.

At baseline, a difference between groups was observed on the sway area (p < 0.05). Healthy subjects showed no statistical difference among the four recordings (repeatability of measurements from 85-100%). Vestibular patients showed differences among the four recordings on the area and the length/average speed of sway (p <0.05); individual differences from baseline exceeding the limits of agreement were observed on the sway area. A decrease on the Dizziness Handicap Inventory (≥18 points) was observed on 19 patients, from whom 12 (63, 95% CI 53-73%) showed a change on the sway area (eyes closed) that was larger than the limits of agreement.

In healthy subjects, intra-subject repeated recordings of the area and the length/average speed of sway may be reliable at intervals of 4, 6 and 8 weeks. The sway area (without vision) may be a useful sway component, among others, to follow-up vestibular patients with chronic, peripheral disease during rehabilitation.