Abstract
Using Contraves' computerized rotary chair system, sinusoidal harmonic acceleration (SHA) test and trapezoid rotation (TR) test were performed on the same day on 25 normal subjects and 110 patients with the peripheral vestibular disorders, to evaluate the meaning of “phase lag” detected by the SHA test.
The patients tended to show lower “gain” of VOR by TR test, and a more dominant “phase lag” was recorded by SHA test.
A “phase lag” was detected by SHA test in 56.5% of the subjects, and this incidence was similar to that of “vestibular asymmetry” detected by TR test.
Although “vestibular asymmetry” was frequently detected in the vertiginous stage, “phase lag” was noted not only in the vertiginous stage but also in the non-vertiginous stage of the peripheral vestibular disorder.
“Phase lag” was thought to be a useful parameter of abnormality of the vestibular system.
