title: Changes in cochlear function related to acoustic stimulation of cervical vestibular evoked myogenic potential stimulation.
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 130 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 6 ms and was presented at 500 Hz and 130 dB peSPL. Békésy thresholds at 0.125-8 kHz and DPOAE I/O growth functions with stimulation at 0.75 and 3 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 (0.5-1.35 dB) and 3 kHz (1.6-2.1 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 8 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.
authors.affiliation: Department of ENT - Head and Neck Surgery, Linköping University Hospital, UHL, County Council of Östergötland, 581 85 Linköping, Sweden; Department of Audiology and Neurotology, Karolinska Hospital, Stockholm, Sweden. Electronic address: anna-karin.stromberg@regionostergotland.se.
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Strömberg
authors.affiliation: Department of Clinical Science, Intervention and Technology, Division of Ear, Nose and Throat Diseases, Unit of Technical and Experimental Audiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Åke
authors.initials: Å
authors.lastname: Olofsson
authors.affiliation: Department of Audiology and Neurotology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Westin
authors.affiliation: Department of Audiology and Neurotology, Karolinska Hospital, Stockholm, Sweden; Department of Clinical Science, Intervention and Technology, Karolinska Institute Stockholm, Sweden.
authors.forename: Maoli
authors.initials: M
authors.lastname: Duan
authors.affiliation: Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Stenfelt
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000293:Adolescent; D000328:Adult; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology*; D002138:Calibration; D003051:Cochlea / Q000502:physiology*; D003198:Computer Simulation; D007758:Ear, Inner / Q000502:physiology; D005260:Female; D006309:Hearing / Q000502:physiology; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology; D006320:Hearing Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D013997:Time Factors; D058585:Vestibular Evoked Myogenic Potentials / Q000502:physiology*; D055815:Young Adult
keywords: DPOAE; Hearing; Noise; Tone burst; VEMP