Ocular Vestibular Evoked Myogenic Potentials Produced by Stimulation With Bone-conducted Vibration in Healthy Subjects / 대한평형의학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: To provide the empirical basis for using ocular vestibular evoked myogenic potentials (oVEMPs) in response to bone-conducted vibration (BCV) stimulation to indicate vestibular function in normal subjects. MATERIALS AND METHODS: In response to bone-conducted tone burst (90 dB nHL and 100 dB nHL with frequencies 500 Hz and 1,000 Hz, the oVEMPs were measured in 45 healthy controls. The early negative component (n10) of the oVEMP to brief BCV of the forehead and at each mastoid process is recorded by surface electromyography electrodes just beneath the eyes. We used a hand-held vibrator (Bruel and Kjaer 4810 Mini-Shaker) placed on the forehead, in the midline at the hairline (Fz) and at each mastoid process and quantified the individual differences in n10 magnitude, latency and symmetry to Fz and mastoid BCV at each frequency. RESULTS: In normal subjects, n10 responses were symmetrical in the two eyes during Fz and both mastoid stimuli and the latencies of the onset were consistent among subjects. Response rate is similar between Fz and mastoid stimuli. However, at each stimulation site, response rate is higher on 500 Hz than on 1,000 Hz stimulation. During the mastoid stimuli, the onset latency is slightly shorter and amplitude is larger than the Fz stimuli. The average amplitudes decreased with age and average latency (to peak) increased slightly with increasing age. CONCLUSION: Clear oVEMP responses to bone-conducted Fz and mastoid stimuli were evoked from normal subjects. It is concluded that bone-conducted stimuli as well as air conduction can evoke myogenic potentials from the ocular muscles.