Standardization of Rotatory Chair Velocity Step and Sinusoidal Harmonic Acceleration Tests in Adult Population, MOHAMED F.M. AHMED
Abstract
Objective: To standardize the rotatory chair sinusoidal harmonic acceleration and velocity step tests in adult popu-lation.
Study Design: Prospective study.
Setting: Clinical tertiary care vestibular function test center.
Patients: One hundred normal participants (66 male and 34 females without suspected vestibular disorder) evaluated with bithermal binaural caloric and sinusoidal and step-velocity rotary chair (RC) tests.
Intervention: Hearing, VNG and RC tests.
Material and Methods: All participants were selected according to the following criteria: (1) No past history of dizziness; (2) Normal otological examination; (3) Normal hearing evaluation; (4) Normal VNG testing; (5) 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 semi-circular canals were close to the plane of stimulus (30º forward tilt), The rotational chair testing paradigms used in this study were: (A) The Rotational Sinu-soidal Harmonic Acceleration (SHA) Test and (B) The Rota-tional Velocity Step (RVS) Test.
Results: The demographic criteria for the study group as following: the age range was 18-56 years with mean age of 36.47 years; the gender distribution was 66% for males and 34% for females. The mean, standard deviation, range and 95% confidence limits of the SHA and RVS test was calculated and compared with the manufacture normal values. It demon-strated that no significant statistical difference between our lab test results and the manufacture measured values of the rotational SHA test and the RVS; this could be attributed to the strict selection criteria of the study group.
Conclusion: In summary, the information gleaned 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 neces-sary for diagnosing vestibular abnormalities, assists in identification of peripheral vestibular deficits not detectable with existing procedures. The major clinical advantage of comput-erized 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.