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The vestibulo-ocular reflex (VOR) acts to maintain a clear and stationary image of the visual world during movements of the head. Accurate measurement of the VOR is therefore an important clinical method for evaluation of the vestibular system. We applied a new method of computerized vestibular testing, the Vestibular Autorotation Test (VAT), which is based on 18 seconds of active head movements. The VAT was used to prospectively study the horizontal VOR of nine patients with cancer who were being treated with cisplatin. Patients were instructed to move their heads in the horizontal plane in synchrony with audible clicks of a linearly increasing frequency range, from 0.5 to 6.5 Hz. Electro-oculographic (EOG) eye movements and head velocity were monitored and digitized to compute horizontal VOR gain and phase from 2 to 6 Hz. Patients were tested with the VAT before the initial cisplatin treatment, and then before each subsequent cisplatin treatment. The pretreatment gains and phases were compared with those obtained after the final cisplatin treatment. Results showed decreased VOR gains at 3.1 Hz, 3.9 Hz, and 5.1 Hz, and increased phase lags at 3.1 Hz and 3.9 Hz. We conclude that VAT analysis of the horizontal VOR at frequencies 3 to 5 Hz is useful for detection and monitoring of cisplatin vestibulotoxicity.

\s=b\The vestibulo-ocular reflex (VOR) is seldom tested above 2 Hz, in spite of the higher-frequency components that stimulate it during natural head movements. We tested the horizontal VOR in ten normal subjects during 18 s of active, side-to\x=req-\ side head motion over a frequency range from 2 to 6 Hz. Audible clicks were used as a linearly increasing frequency cue. Head velocity was monitored. The two experimental conditions were head movement while fixating a stationary wal l \x=req-\ mounted target in dim light, and head movement in darkness with an imagined stationary target. Computed gain and phase results of the two test conditions were not significantly different, due to inactivation of the smooth pursuit system above 2 Hz. We conclude that higher\x=req-\ frequency VOR responses can be tested in the light by a brief, low-cost test, which does not require expensive rotating machinery.A frequent complaint among pa¬ tients with dizziness is a sensa¬ tion of dizziness following head move-

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