Comparative studies of computerized trapezoid rotation test and sinusoidal harmonic acceleration test

Abstract

This study was performed to compare the clinical data from the two different kind of rotation tests: Trapezoid Rotation (TR) test (±2, 4, 6, 8, 10°/sec2, 10") and Sinusoidal Harmonic Acceleration (SHA) test (0.01, 0.02, 0.04, 0.08, 0.16Hz).Twenty five normal subjects and 110 patients with peripheral vestibular disorders were examined by these two rotation methods with Contraves' computerized rotary chair on the same day. The following results were obtained:1) The finding of vestibular asymmetry detected by the two rotation methods agreed in 75.9 % of all patients, while the remainder showed the different results. The abnormality detected by TR test was found in 57.2% of the patients, which was higher than that of SHA test (45.5%). 2) In normal subjects, the maximum slow-phase velocity of per-rotatory nystagmus by TR test was greater than that of SHA test using the approximate value of the angular acceleration. The cause of difference between the results of these two rotation methods was thought to be that the maximum slow-phase eye velocity of per-rotatory nystagmus was more clearly induced by TR test than by SHA test.3) As to the finding of abnormal VOR-Gain, the results of TR test coincided with that of SHA test in 100% of cases with bilateral vestibular disorders. In cases with unilateral vestibular disorder, however, the rate of the abnormality detected by SHA test was higher than that of TR test. Namely, the abnormality of VOR-Gain in nystagmus directed to the affected side was found in 22.6% by SHA test, and in 11.3% by TR test.