Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6286892 | Hearing Research | 2016 | 7 Pages |
Abstract
Evaluation of cervical evoked myogenic potentials (c-VEMP) is commonly applied in clinical investigations of patients with suspected neurotological symptoms. Short intense acoustic stimulation of peak levels close to 130Â dB SPL is required to elicit the responses. A recent publication on bilateral significant sensorineural hearing loss related to extensive VEMP stimulation motivates evaluations of immediate effects on hearing acuity related to the intense acoustic stimulation required to elicit c-VEMP responses. The aim of the current study was to investigate changes in DPOAE-levels and hearing thresholds in relation to c-VEMP testing in humans. More specifically, the current focus is on immediate changes in hearing thresholds and changes in DPOAE-levels at frequencies 0.5 octaves above the acoustic stimulation when applying shorter tone bursts than previously used. Hearing acuity before and immediately after exposure to c-VEMP stimulation was examined in 24 patients with normal hearing referred for neurotologic testing. The stimulation consisted of 192 tonebursts of 6Â ms and was presented at 500Â Hz and 130Â dB peSPL. Békésy thresholds at 0.125-8Â kHz and DPOAE I/O growth functions with stimulation at 0.75 and 3Â kHz were used to assess c-VEMP related changes in hearing status. No significant deterioration in Békésy thresholds was detected. Significant reduction in DPOAE levels at 0.75 (0.5-1.35Â dB) and 3Â kHz (1.6-2.1Â dB) was observed after c-VEMP stimulation without concomitant changes in cochlear compression. The results indicated that there was no immediate audiometric loss related to c-VEMP stimulation in the current group of patients. The significant reduction of DPOAE levels at a wider frequency range than previously described after the c-VEMP test could be related to the stimulation with shorter tone bursts. The results show that c-VEMP stimulation causes reduction in DPOAE-levels at several frequencies that corresponds to half the reductions in DPOAE levels reported after exposure to the maximally allowed occupational noise for an 8Â h working day. Consequently, extended stimuli intensity or stimulation repetition with c-VEMP testing should be avoided to reduce the risk for noise-induced cochlear injury.
Keywords
Related Topics
Life Sciences
Neuroscience
Sensory Systems
Authors
Anna-Karin Strömberg, Ã
ke Olofsson, Magnus Westin, Maoli Duan, Stefan Stenfelt,