Standardization of rotatory chair velocity step and sinusoidal harmonic acceleration tests in an adult population

Abstract

Objective To standardize the rotatory chair sinusoidal harmonic acceleration and velocity step tests in an adult population. Study design Prospective study. Setting Clinical tertiary care vestibular function test center. Patients One hundred normal participants (66 men and 34 women without suspected vestibular disorder) were evaluated using bithermal binaural caloric and sinusoidal and step-velocity rotary chair tests. Intervention Hearing, videonystagmography, and rotary chair tests. Materials and methods All participants were selected according to the following criteria: (a) no history of dizziness; (b) normal otological examination; (c) normal hearing evaluation; (d) normal videonystagmography testing; and (e) rotational chair testing. The patient was positioned and secured to the rotational chair with the patient's head restrained and adjusted so that both lateral semicircular canals were close to the plane of stimulus (30΀ forward tilt), the rotational chair testing paradigms used in this study were: (a): the rotational sinusoidal harmonic acceleration (SHA) test and (b): the rotational velocity step test. Results The demographic criteria for the study group were as follows: the age range was 18-56 years, mean age 36.47 years, and 66% of the participants were men and 34% were women. The mean, SD, range, and 95% confidence limits of the SHA and rotational velocity step test were calculated and compared with the manufacturer's normal values. No statistically significant differences were found between our lab test results and the manufacturer-measured values of the rotational SHA test and the rotational step velocity test (SVT); this could be attributed to the strict selection criteria of the study group. Conclusion In summary, the information obtained from rotational chair testing may provide valuable information in the diagnosis and subsequent management of patients with vestibular disorders. It completes the spectrum of tests necessary for the diagnosis of vestibular abnormalities and aids the identification of peripheral vestibular deficits not detectable with existing procedures. The major clinical advantage of computerized rotational testing is the ability to produce angular accelerations that can be precisely controlled and repeated. Multiple stimuli of varying intensities can be applied to the vestibular system within a relatively short time.