ABSTRACT
BACKGROUND: Cervical (cVEMP) and ocular (oVEMP) vestibular-evoked myogenic potentials are short-latency manifestations of vestibulo-ocular and vestibulocollic reflexes that originate from the utricle and saccule. The aim of this study was to determine whether simultaneously recording cVEMP and oVEMP more reliably detects the reflex responses than when making separate recordings. METHODS: Both simultaneous recordings and conventional separate recordings of the cVEMP and oVEMP responses to air-conducted tone bursts were obtained in 39 healthy subjects. p13 and n10 latencies, and p13-n23 and n10-p16 amplitudes of cVEMP and oVEMP waveforms were measured, respectively. The asymmetry ratios (ARs) of the amplitudes were calculated. RESULTS: In cVEMP testing, the p13 latencies and p13-n23 amplitudes did not differ significantly between simultaneous and conventional separate recordings. In oVEMP testing, the n10 latencies measured in simultaneous recordings showed a small but statistically significant prolongation compared to the results in separate recordings. Moreover, the n10-p16 amplitudes were significantly larger in the simultaneous recordings. The AR of simultaneous recordings of cVEMP and oVEMP did not differ between the two recording methods. CONCLUSIONS: Simultaneously recording cVEMP and oVEMP provides a reliable test and could be a clinically useful and simplified diagnostic tool for evaluating dizzy patients.
Subject(s)
Humans , Reflex , Saccule and UtricleABSTRACT
BACKGROUND: Cervical (cVEMP) and ocular (oVEMP) vestibular-evoked myogenic potentials are short-latency manifestations of vestibulo-ocular and vestibulocollic reflexes that originate from the utricle and saccule. The aim of this study was to determine whether simultaneously recording cVEMP and oVEMP more reliably detects the reflex responses than when making separate recordings. METHODS: Both simultaneous recordings and conventional separate recordings of the cVEMP and oVEMP responses to air-conducted tone bursts were obtained in 39 healthy subjects. p13 and n10 latencies, and p13-n23 and n10-p16 amplitudes of cVEMP and oVEMP waveforms were measured, respectively. The asymmetry ratios (ARs) of the amplitudes were calculated. RESULTS: In cVEMP testing, the p13 latencies and p13-n23 amplitudes did not differ significantly between simultaneous and conventional separate recordings. In oVEMP testing, the n10 latencies measured in simultaneous recordings showed a small but statistically significant prolongation compared to the results in separate recordings. Moreover, the n10-p16 amplitudes were significantly larger in the simultaneous recordings. The AR of simultaneous recordings of cVEMP and oVEMP did not differ between the two recording methods. CONCLUSIONS: Simultaneously recording cVEMP and oVEMP provides a reliable test and could be a clinically useful and simplified diagnostic tool for evaluating dizzy patients.
Subject(s)
Humans , Reflex , Saccule and UtricleABSTRACT
BACKGROUND AND OBJECTIVES: The ocular vestibular evoked myogenic potential (OVEMP) is a recently discovered test of labyrinthine function, analogous to the cervical VEMP. Recent works have demonstrated the existence of OVEMPs, which likely reflect otolith-ocular reflex. The purpose of this study was to identify the optimal plateau and rise/fall times of short tone bursts to detect OVEMPs in healthy subjects. MATERIALS AND METHODS: Thirteen healthy subjects (26 ears) were included in this study. Surface electromyographic activity was recorded from active electrodes placed inferior to each eye. Stimulation with 500 Hz short tone bursts was used. We used a variety of plateau and rise/fall times. Three different plateau times (1, 2, and 3 ms) and rise/fall times (0.5, 1, and 2 ms) were used. The incidence, amplitudes and latencies were compared. RESULTS: VEMP responses were clearly observed in all 26 ears at the plateau time of 2 ms and two rise/fall times (0.5 and 1 ms). The amplitudes in the individual ears tested were lower at the rise/fall time of 2 ms than at the other conditions. The amplitudes were lower at the plateau time of 3 ms compared to the other conditions. When the rise/fall time was prolonged from 0.5 to 2 ms, the n1 and p1 latencies were prolonged in parallel. However, there was no such change in latencies according to the plateau times. CONCLUSIONS: Our findings show that the ideal stimulation pattern for evoking OVEMP is at the rise/fall times of 0.5 or 1 ms and the plateau time of 2 ms. The waveform morphology of the VEMP responses observed with this stimulation pattern was simultaneously the most constant and marked.