COMPARISON OF VESTIBULAR AUTOROTATION AND CALORIC TESTING

The two most common stimuli of the vestibular system for diagnostic pu rposes are caloric and rotational head movements, Caloric stimulation, by delivering thermal energy to the lateral semicircular canal, is a well-studied method of vestibular testing, and its clinical usefulness has been established, Vestibular autorotation testing uses high-frequ ency (2 to 6 Hz), active head movements to stimulate the horizontal an d vertical vestibulo-ocular reflex to produce measurable eye movements that can be used to calculate gain and phase, We compared the alterna te bilateral bithermal caloric results with the vestibular autorotatio n test results obtained from 39 patients with peripheral vestibular di sorders and from 10 patients with acoustic neuroma, In the peripheral disorder group, only 2 of 14 patients with equal caloric response (<20 % reduced vestibular response) had a normal vestibular autorotation te st result, No patients with a reduced vestibular response greater than 21% had a normal vestibular autorotation test result, In the acoustic neuroma group, four patients had a normal reduced vestibular response , but all patients had an abnormal vestibular autorotation test result , We conclude that testing both the horizontal and vertical vestibule- ocular reflexes in their physiologic frequency range with the vestibul ar autorotation test provides additional information that could be mis sed by conventional caloric testing, Therefore high-frequency rotation al testing is a valuable addition to the vestibular test battery.