The effect of rise/fall time of 500 Hz short tone bursts on cervical vestibular evoked myogenic potential

Abstract

BACKGROUND: Cervical vestibular evoked myogenic potential (cVEMP) is a biphasic potential recorded from the Sternocleidomastoid muscle in response to loud acoustic stimulation and assesses the intactness of the Sacculocolic pathway. The literature on clinical utility of cVEMP has been growing rapidly, though not without inconsistencies despite involving alike population. A close scrutiny of the methods across such studies revealed an inconsistent use of stimulus parameters; especially rise/fall times (RFTs). However the effect of RFTs on cVEMP has been largely unexplored. OBJECTIVE: The study aimed at exploring the effect of varying RFTs on cVEMP and obtaining optimum RFT to enable reliable recording of cVEMPs. METHODS: The cVEMPs were recorded from both ears of 30 healthy individuals with normal audio-vestibular system using 500 Hz short tone-bursts (STBs) at 95 dB nHL and varying the RFTs from 1 to 8 ms at all integer values. RESULTS: There was significant prolongation of latencies with increasing RFTs (p < 0.05). The largest amplitudes were obtained for 2 to 3 ms RFTs, though significantly smaller amplitude was obtained only for 8 ms RFT (p < 0.05), thereby rendering 8 ms RFT unfit for cVEMP recording. The 1 ms RFT produced smallest variability across individuals and would also result in lesser duration of exposure to loud sound. CONCLUSIONS: The RFT of 1 ms of 500 Hz STBs are optimum for recording cVEMPs. This is owing to large amplitudes and least variability demonstrated for this RFT.

Air-Conducted Vestibular Evoked Myogenic Potential Testing in Children, Adolescents, and Young Adults: Thresholds, Frequency Tuning, and Effects of Sound Exposure

“…Acoustic trauma secondary to VEMP testing has been observed in adults (Krause et al 2013; Mattingly et al 2015; Stromberg et al 2016) in the form of decreased audiometric thresholds, distortion product otoacoustic emission (DPOAE) amplitudes, and subjective symptoms. Therefore, in the context of VEMP testing, stimulus intensity, duration, rise/fall and plateau time should be considered when performing air-conducted VEMPs to minimize sound exposure, as these parameters will affect total sound energy exposure that a person will receive (Colebatch & Rosengren 2014; Singh & Apeksha 2014).…”

Big Stimulus, Little Ears: Safety in Administering Vestibular-Evoked Myogenic Potentials in Children

“…While reducing the stimulus intensity may not be an option, given the otolith organ's high threshold (i.e., 110-115 dB SPL) (Colebatch et al, 1994;Welagampola and Colebatch, 2001;Janky and Shepard, 2009), reducing stimulus duration or using a bone-conducted stimulus can decrease overall noise exposure. Singh and Apeksha (2014) noted that a 1-msec rise/fall time with 0-msec plateau resulted in larger cVEMP amplitudes and reduced test-retest variability in the waveforms. Reducing rise/fall times has the added benefit of decreasing the stimulus duration, which would lessen the sound energy exposure (Singh and Apeksha, 2014).…”

“…Singh and Apeksha (2014) noted that a 1-msec rise/fall time with 0-msec plateau resulted in larger cVEMP amplitudes and reduced test-retest variability in the waveforms. Reducing rise/fall times has the added benefit of decreasing the stimulus duration, which would lessen the sound energy exposure (Singh and Apeksha, 2014). This is useful when needing to complete several trials without overexposing the patient/participant to excessive amounts of sound.…”

“…When using this calculation for children, consider adding 3 dB to the stimulus level. Additional care can be taken by reducing stimulus rise and fall times (Shall, 2009;Singh and Apeksha, 2014), starting at lower stimulus intensities (i.e., 115 dB SPL) for children and then increasing the stimulus intensity only if necessary.…”

Effect of personal music system use on sacculocollic reflex assessed by cervical vestibular-evoked myogenic potential: A preliminary investigation

“…This electrode placement was similar to previous studies. [ 46 47 48 49 50 ] Absolute impedance and interelectrode impedance were maintained below 5 kΩ and 2 kΩ, respectively. The participants were instructed to turn their heads away from the side of stimulation in order to tense the sternocleidomastoid muscle (SCM).…”