メニエール病手術例の回転検査による評価

抄録

Sinusoidal rotational test and vestibular auto-rotation test (VAT) were per-formed on eight patients with Meniere's disease before and after vestibular nerve section. Two weeks after the operation, almost all the patients consistently showed response asymmetry toward the healthy ear at all stimulus frequencies and reduction in sensitivity to rotational stimuli at 0.01 Hz in the sinusoidal rotational test. Prior to surgery, the VOR time constant varied depending on the residual vestibular function of each patient. The time constant then dropped to a mean of 4.2 seconds 14 days afteroperation. In the VAT, almost all patients showed gain reduction at all frequencies on the seventh post-operative day. These findings suggest that the response asymmetry and the gain at 0.01Hz in the sinusoidal rotational test are valuable in evaluating the time course of compensation of the vestibular function after surgery and that the VOR time constant is useful in determining whether the vestibular nerve is cut properly.