Aging effect and test-retest reliability of the sinusoidal harmonic acceleration test and velocity step test using nanotorque rotatory chair

INTRODUCTION: Rotatory chair testing has been used to evaluate horizontal canal function. Frequently used tests include sinusoidal harmonic acceleration test (SHAT) and velocity step test (VST). OBJECTIVES: Assessment of age effect on the SHAT and VST and assessment of test-retest reliability of the parameters of those two tests. METHODS: A prospective study was performed on 100 subjects with no ear or vestibular complaints and normal vestibular evaluation. They were divided into two groups; Group A: below 50 years of age and Group B: 50 years of age or above. SHAT was presented at frequencies 0.02, 0.04, 0.08, 0.16, 0.32, 0.64 Hz with a peak velocity of 60°/s. VST was performed using a maximum velocity of 100°/s with acceleration and deceleration of 200°/s(2.) Thirty subjects were tested twice to assess reliability. RESULTS: Study participants ranged in age from 20 to 67 years. Regarding group A, the mean age was 30.92 ± 7.31 and 55.36 ± 4.61 for group B. No significant differences were found in SHAT parameters between the two groups. As well, there was no significant difference in VST per-rotatory time constant, however, post-rotatory time constant was significantly longer for Group B (P value < 0.05). Intraclass correlation coefficient (ICC) values showed moderate to good reliability (ICC 0.580–0.818) for SHAT parameters for the lower frequencies and indicated moderate reliability for VST time constant (ICC 0.509–0.652). CONCLUSIONS: Age has no significant effect on the parameters of SHAT and VST. Test-retest reliability is generally good for both tests.