The Effects of Plateau Time on Vestibular-evoked Myogenic Potentials Triggered by Tone Bursts

Vestibular-evoked myogenic potentials (VEMPs) can be triggered by acoustic, vibratory or galvanic stimuli. However, each method has drawbacks for studying if the vestibulocollic reflex is intact in the patients tested. We used air-conducted VEMPs as a screening test to examine the integrity of the sacculocollic reflex. In a previous study, we defined the optimal rise fall time of short tone bursts (STBs) to evoke VEMPs. In this paper, we studied the optimal plateau time of tone bursts to evoke VEMPs. Four different plateau times (1, 2, 5 and 10 ms) were used in a random order to test 26 normal ears. VEMP responses (p13 n23) triggered by the tone bursts were clearly observed in all ears. When the plateau time was increased in order from 1 to 10 ms, the latencies (p13, n23) and interval (p13-n23) were also increased in parallel, although significant differences were not observed between some plateau times. Considering the latencies and interval together for the four plateau times, the variances were smallest for the 2 ms plateau time, meaning that it caused the smallest interaural VEMP differences. The amplitude or relative amplitude in individual ears was lowest for the 1 ms plateau time, while it was comparable for the other three plateau times. In conclusion, we recommend that the ideal stimulation pattern for evoking STB VEMPs is as follows: frequency 500 Hz; stimulation repetition rate 5 Hz; rise fall time 1 ms; and plateau time 2 ms. The waveform morphology of the VEMP responses observed with this stimulation pattern was simultaneously the most constant and marked.     

The effect of rise/fall time on vestibular-evoked myogenic potential triggered by short tone bursts.

Vestibular-evoked myogenic potentials (VEMPs) are used more and more frequently as a clinical tool to test if the sacculocollic reflexes are intact in patients. They can be evoked by short tone bursts (STBs) as well as by clicks. Although most previous studies used traditional clicks to generate VEMP responses, our clinical experience showed that STBs were prone to evoke them more clearly, at least in some patients. Four kinds of STB stimulation patterns in a random order were used to test 22 ears using changing rise/fall times (0.3, 1, 3 and 10 ms). VEMP responses (p13/n23) triggered by these patterns were clearly observed in all 22 ears. When the rise/fall time was prolonged from 0.3 to 10 ms, the p13 latency was prolonged in parallel. There was a similar trend for the n23 latency, although a significant difference was not attained between 0.3 ms and 1 ms rise/fall times. Considering the p13 and n23 latencies for the 4 rise/fall times, the variances were smallest for the 1 ms stimulation, meaning that it caused the smallest interaural latency differences. The amplitude or relative amplitude in the individual ears tested was lowest for the 10 ms stimulation, being comparable among the other 3 rise/fall times. In conclusion, the 1 ms rise/fall time was a remarkable stimulation pattern because its VEMP responses were simultaneously more constant and conspicuous.     

The Effect of Rise/Fall Time on Vestibular-evoked Myogenic Potential Triggered by Short Tone Bursts

Vestibular-evoked myogenic potentials (VEMPs) are used more and more frequently as a clinical tool to test if the sacculocollic reflexes are intact in patients. They can be evoked by short tone bursts (STBs) as well as by clicks. Although most previous studies used traditional clicks to generate VEMP responses, our clinical experience showed that STBs were prone to evoke them more clearly, at least in some patients. Four kinds of STB stimulation patterns in a random order were used to test 22 ears using changing rise/fall times (0.3, 1, 3 and 10 ms). VEMP responses (p13/n23) triggered by these patterns were clearly observed in all 22 ears. When the rise/fall time was prolonged from 0.3 to 10 ms, the p13 latency was prolonged in parallel. There was a similar trend for the n23 latency, although a significant difference was not attained between 0.3 ms and 1 ms rise/fall times. Considering the p13 and n23 latencies for the 4 rise/fall times, the variances were smallest for the 1 ms stimulation, meaning that it caused the smallest interaural latency differences. The amplitude or relative amplitude in the individual ears tested was lowest for the 10 ms stimulation, being comparable among the other 3 rise/fall times. In conclusion, the 1 ms rise/fall time was a remarkable stimulation pattern because its VEMP responses were simultaneously more constant and conspicuous.     

The influence of clicks versus short tone bursts on the vestibular evoked myogenic potentials

OBJECTIVE: Vestibular evoked myogenic potential (VEMP) has become a diagnostic tool to evaluate the integrity of sacculo-collic reflex. To obtain a more consistent VEMP response in normal-hearing subjects, we examine whether clicks or short tone bursts are more effective in eliciting VEMP responses. DESIGN: Prospective study. Twenty-nine normal-hearing volunteers (58 ears) were given VEMP tests. Clicks and short tone bursts were presented alternately to evoke VEMPs. The latencies of peak p13 and n23, peak-to-peak interval and amplitude (p13-n23) were measured and compared. RESULTS: Click stimulation of 57 ears (98%) produced VEMPs (C-VEMPs), whereas 51 (88%) revealed positive short tone burst-evoked VEMPs (STB-VEMPs), exhibiting a significant difference (p < 0.05). Furthermore, C-VEMPs displayed shorter latency, longer interval and larger amplitude than STB-VEMPs, with a significant difference (p < 0.05), respectively. CONCLUSIONS: C-VEMPs had a higher response rate, shorter latency, and larger amplitude than STB-VEMPs. These findings suggest that click is superior to short tone burst to trigger VEMPs. Because C-VEMPs have a shorter p13 latency than STB-VEMPs, the interpretation of prolonged latency differs in each stimulus condition.     

Effects of stimulus conditions on vestibular evoked myogenic potentials in healthy subjects

Background: Characteristics of vestibular evoked myogenic potentials (VEMPs) depend on stimulus conditions.

Objective: To determine the optimal stimulus conditions for cervical and ocular VEMPs.

Methods: Participants were 23 healthy subjects. We compared air-conducted cervical and ocular VEMPs elicited by various tone-burst conditions (frequencies 500–1,000?Hz, rise/fall times 1–2?ms, and plateau times 0–6?ms) with an intensity of 105?dB normal hearing level. Effects of simultaneous contralateral masking noise on VEMPs were also evaluated.

Results: The largest cervical VEMP amplitudes were elicited by 500–750?Hz and 2–6?ms plateau time-tone-bursts, and the largest ocular VEMP amplitudes by 750?Hz and 2–4?ms plateau time-tone-bursts. Repeatability of the latency was better at 1?ms than at 2?ms rise/fall time in both VEMPs. In both VEMPs, masking noise reduced amplitude, and in ocular VEMP, amplitudes were significantly larger at the left ear stimulation than the right.

Conclusion: Optimal tone-burst stimulation for both VEMPs seemed to be 500–750?Hz frequency and 1/2/1?ms rise/plateau/fall time without contralateral masking noise. Ocular VEMP amplitudes from left ear stimulation were originally larger than those from right ear stimulation.     

Comparison of tone burst and tapping evocation of myogenic potentials in patients with chronic otitis media

OBJECTIVE: Vestibular evoked myogenic potential (VEMP) has recently been broadly studied in cochleo-vestibular disorders to elucidate its mechanism. Because it is evoked by loud sound stimulation, impairment of the sound transmission through the middle ear may affect VEMP results. This study aims to compare the response rate of VEMPs using the tone burst method and the tapping method in patients with chronic otitis media (COM). DESIGN: Fourteen patients (22 ears) with conductive hearing loss due to COM were subjected to VEMP tests using both the tone burst method and the tapping method. Each ear was stimulated by a short-tone burst (95 dB nHL, 500 Hz), followed by tapping on the forehead with a tendon hammer, 200 times at a frequency of 5 Hz. RESULTS: Thirteen (59%) of the 22 ears showed positive VEMPs using the tone burst method, whereas 20 ears (91%) displayed positive VEMPs by the tapping method (p < 0.05). The latencies of wave p13 and n23, and the amplitude p13-n23 using the tone burst method were 13.4 +/- 4.1 msec, 20.5 +/- 4.6 msec, and 77.2 +/- 17.2 microV, respectively. These results do not significantly differ from those obtained using the tapping method. In ears with perforated eardrums (N = 11), five ears (45%) displayed positive VEMPs by the tone burst method; compared with nine ears (82%) with positive VEMPs using the tapping method, representing a nonsignificant difference. In ears with healed eardrums (N = 11), eight ears exhibited positive VEMPs by tone burst, with a mean air-bone gap of 25.6 +/- 15.2 dB at 500 Hz, in contrast to a gap of 30.0 +/- 22.9 dB in three ears without VEMPs, indicating no significant difference. CONCLUSIONS: When stimulating sound is attenuated by middle ear pathology, VEMPs are expected to be poorly elicited. Under such conditions, myogenic potentials may be evoked with the tapping method to elicit the absent VEMPs that result from middle ear or inner ear pathology.     

The effect of click repetition rate on vestibular evoked myogenic potential

Vestibular evoked myogenic potentials (VEMPs) generated by click stimulation and recorded on the sternocleidomastoid muscle have been used as a test of vestibular reflexes. Various parameters of the stimulus and recording setting have been studied. However, the influence of stimulation repetition rate of VEMPs and the most optimal stimulation rate for clinical use have not yet been defined. Each ear of 12 normal adults was tested at five different click stimulation rates (1 Hz, 5 Hz, 10 Hz, 15 Hz and 20 Hz) in random order. VEMP responses were evident in all 24 ears stimulated with 1 Hz, 5 Hz and 10 Hz. One ear was void of response at 15 Hz stimulation and nine ears at 20 Hz stimulation. The relative amplitude or the rank of amplitude in individual ears was higher at 1 Hz and 5 Hz stimulation, progressively decreasing as the stimulation rate increased. Comparisons of p13 and n23 latencies showed no difference among five stimulation rates, but variance was greatest at 20 Hz stimulation and smallest at 1 Hz. VEMPs generated at lower stimulation repetition rate seemed to be more marked and constant. However, with regard to examination time and patient compliance, a 5 Hz stimulus is advisable if both short examination time and higher signal/noise ratio are required.     

Effect of white noise on vestibular evoked myogenic potentials

OBJECTIVES: To clarify if p13-n23 of vestibular evoked myogenic potentials (VEMPs) is independent of cochlear afferents. METHODS: Twenty normal volunteers and 10 patients with hemifacial palsy enrolled into this study. VEMP and auditory brainstem responses (ABRs) were recorded with or without white noise (WN, 75 dBnHL or 95 dBnHL) ipsilaterally or contralaterally to the stimulated ear. Short tone bursts (STBs) of 0.5 kHz (95 dBnHL, rise/fall time=1 ms, plateau time=2 ms) were presented though headphones. For recording VEMPs surface electromyographic activity was recorded in the supine subjects form symmetrical sites over the upper half of each SCM with a reference electrode over the upper sternum. RESULTS: The amplitude of p13-n23 significantly decreased during exposure of the contralateral ear as well as the ipsilateral ear to 95 dBnHL WN in normal volunteers (41% reduction by the ipsilateral exposure and 38% reduction by the contralateral exposure). Exposure to 75 dBnHL WN caused only minimal reduction of the amplitudes of p13-n23 (5% reduction) although it caused remarkable reduction of the amplitudes of V-SN(10) (ABRs) (23% reduction). However, 95 dBnHL WN exposure showed no effect on the amplitudes of p13-n23 in the ipsilateral side to hemifacial palsy. CONCLUSION: Overall the data are in favor of the hypothesis that cochlear afferents could affect the amplitude of p13-n23 only through the stapedial reflex, although our data might not be strict proof of an absence of influence of cochlear afferents' activity.     

Effect of click duration on vestibular-evoked myogenic potentials

CONCLUSIONS: The 0.5-VEMP demonstrated a more prominent waveform morphology than either the 0.1- or 0.2-VEMPs. In addition, the 0.5-VEMP had smaller interaural latency differences than the 1.0-VEMP. These findings suggest that 0.5 ms is superior to other click durations in terms of yielding VEMP responses for clinical use. OBJECTIVE: In order to establish the ideal stimulus condition for vestibular-evoked myogenic potentials (VEMPs), we studied the use of various click durations to generate different response patterns in normal subjects. The influence of click durations on VEMPs is described and the optimal stimulation duration for clinical use is suggested. MATERIAL AND METHODS: This was a prospective study. Eighteen healthy volunteers (36 ears) underwent VEMP tests. Four click durations (0.1, 0.2, 0.5 and 1.0 ms) were used in a random order to elicit VEMP responses (0.1-, 0.2-, 0.5- and 1.0-VEMP, respectively). The latency of each peak (p13, n23), the peak-to-peak interval and amplitude (p 13-n23) and the relative amplitude (defined as the amplitude divided by that of the 0.5-VEMP) were measured and compared. RESULTS: Click stimulation of 34 ears (94%) produced 0.1-VEMP responses, whereas positive 0.2-, 0.5- and 1.0-VEMP responses were observed in 36 (100%). The latencies of peaks p13 and n23 were significantly prolonged between successive stimulus durations from 0.1 to 1.0 ms (p <0.05), in contrast to the p13-n23 intervals (p >0.05). The 1.0-VEMP displayed the largest SDs of latencies and interval among the four different VEMPs. The relative amplitude was significantly increased between successive durations from 0.1 to 0.5 ms (alphaT <0.05), but there was no significant difference between 0.5 and 1.0 ms (alphaT >0.05).     

Comparison of the diagnostic value of 3 T MRI after intratympanic injection of GBCA, electrocochleography, and the glycerol test in patients with Meniere's disease

Conclusions The 0.5-VEMP demonstrated a more prominent waveform morphology than either the 0.1- or 0.2-VEMPs. In addition, the 0.5-VEMP had smaller interaural latency differences than the 1.0-VEMP. These findings suggest that 0.5 ms is superior to other click durations in terms of yielding VEMP responses for clinical use.

Objective In order to establish the ideal stimulus condition for vestibular-evoked myogenic potentials (VEMPs), we studied the use of various click durations to generate different response patterns in normal subjects. The influence of click durations on VEMPs is described and the optimal stimulation duration for clinical use is suggested.

Material and methods This was a prospective study. Eighteen healthy volunteers (36 ears) underwent VEMP tests. Four click durations (0.1, 0.2, 0.5 and 1.0 ms) were used in a random order to elicit VEMP responses (0.1-, 0.2-, 0.5- and 1.0-VEMP, respectively). The latency of each peak (p13, n23), the peak-to-peak interval and amplitude (p13-n23) and the relative amplitude (defined as the amplitude divided by that of the 0.5-VEMP) were measured and compared.

Results Click stimulation of 34 ears (94%) produced 0.1-VEMP responses, whereas positive 0.2-, 0.5- and 1.0-VEMP responses were observed in 36 (100%). The latencies of peaks p13 and n23 were significantly prolonged between successive stimulus durations from 0.1 to 1.0 ms (p<0.05), in contrast to the p13-n23 intervals (p>0.05). The 1.0-VEMP displayed the largest SDs of latencies and interval among the four different VEMPs. The relative amplitude was significantly increased between successive durations from 0.1 to 0.5 ms (α_T<0.05), but there was no significant difference between 0.5 and 1.0 ms (α_T>0.05).     

Vestibular evoked myogenic potentials in newborns

This study presents a novel method for recording vestibular evoked myogenic potential (VEMP) in newborns, used to investigate the maturation of sacculocollic reflex at birth.Twenty full-term newborns aged 2-5 days old were enrolled in this study. During natural sleep, each newborn underwent distortion product otoacoustic emission test, and VEMP test using the head rotation method. For comparison, 20 healthy adults also underwent VEMP test using the same method. Based on adult criteria, 40 newborn ears revealed normal VEMPs in 40%, prolonged VEMPs in 35%, and absent VEMPs in 25%, indicating that great variation exists in the maturation of the sacculocollic reflex at birth. Comparison of VEMP characteristics between healthy newborns and adults revealed nonsignificant difference in the response rate and the latency of n23. However, significant differences existed in the latency of p13, interpeak p13-n23 interval and p13-n23 amplitude between newborns and adults. In conclusion, VEMPs in newborns can be easily recorded by the head rotation method. Prolonged or absent VEMPs in newborns may reflect incomplete maturity of the sacculocollic reflex pathway, especially the myelination. A further large number of newborns receiving MRI scan for other reasons may undergo VEMP test to verify this hypothesis.     

Properties of binaural vestibular evoked myogenic potentials elicited with air-conducted and bone-conducted tone bursts

The purpose of this investigation was to compare the effects of monaural and binaural stimulation on unilaterally-measured vestibular evoked myogenic potential (VEMP) magnitude and latency. The subjects were eighteen normal-hearing adults with no history of vestibular disease. Monaural VEMPs were acquired with air-conducted (AC) and bone-conducted (BC) 500 Hz tone bursts presented at 95 dB nHL and 70 dB nHL, respectively. These stimuli were simultaneously paired with 95 dB nHL contralateral tone bursts at 250, 500, 750, or 1000 Hz during acquisition of binaural VEMPs. Results indicated that AC-VEMP relative magnitudes decreased in each of the binaural conditions compared to the monaural condition. However, no changes in relative magnitude between conditions occurred for BC-VEMPs. Similar latencies were observed for monaural and binaural VEMPs. Differences in bilateral interaction seen between the AC-VEMP and BC-VEMP conditions are consistent with modification of sound transmission through the ear during presentations of binaural sound.     

Properties of binaural vestibular evoked myogenic potentials elicited with air-conducted and bone-conducted tone bursts

The purpose of this investigation was to compare the effects of monaural and binaural stimulation on unilaterally-measured vestibular evoked myogenic potential (VEMP) magnitude and latency. The subjects were eighteen normal-hearing adults with no history of vestibular disease. Monaural VEMPs were acquired with air-conducted (AC) and bone-conducted (BC) 500 Hz tone bursts presented at 95 dB nHL and 70 dB nHL, respectively. These stimuli were simultaneously paired with 95 dB nHL contralateral tone bursts at 250, 500, 750, or 1000 Hz during acquisition of binaural VEMPs. Results indicated that AC-VEMP relative magnitudes decreased in each of the binaural conditions compared to the monaural condition. However, no changes in relative magnitude between conditions occurred for BC-VEMPs. Similar latencies were observed for monaural and binaural VEMPs. Differences in bilateral interaction seen between the AC-VEMP and BC-VEMP conditions are consistent with modification of sound transmission through the ear during presentations of binaural sound.     

Vestibular evoked myogenic potentials in children

OBJECTIVE: The aim of this work is to establish if the vestibular evoked myogenic potentials (VEMPs) could be used as a clinical test of vestibular function in children. MATERIALS AND METHODS: Forty normal hearing children, aged between 3 and 15 years, and classified in preschool and scholar group, have been investigated in order to study normal development of vestibular potentials and to define fundamental parameters of VEMPs, establishing normal data of latencies and amplitude ratio. Electromyographic activity of sternocleidomastoid muscle was recorded while children were laid supine on a bed and asked to raise their head off of the bed in order to activate their neck flexors bilaterally. The saccular receptors were acoustically stimulated with a logon of 500Hz at an intensity of 130dB peSPL presented monaurally through earphones. In each recording, we analysed latencies and amplitudes of the p13 and n23 waves and the amplitude ratio between the two ears. RESULTS: VEMPs were normally detected in all subjects. In preschool group mean p13 and mean n23 latencies were, respectively, 16.13 (+/-2.12)ms and 21.17 (+/-2.77)ms; mean amplitude ratio was 28.49 (+/-18.10). In scholar group mean p13 and n23 were respectively 16.14 (+/-3.48)ms and 21.78 (+/-3.39)ms, while mean amplitude ratio 20.44 (+/-13.24). Comparison of latencies and amplitude ratio between the children groups and control adult group did not showed any significant differences. CONCLUSION: In conclusion, VEMPs could represent a valid and non-invasive technique able to investigate vestibular function in children and, in particular, vestibulo collic reflex.     

Vestibular evoked myogenic potentials are intact after sudden deafness

OBJECTIVE: To evaluate vestibular evoked myogenic potentials (VEMPs) in cases of sudden deafness, and to confirm the noncochlear origin of the VEMPs. STUDY DESIGN: Prospective study. VEMPs, which were evoked by short tone burst (95 dB nHL) stimulation, were recorded in 20 patients with unilateral, idiopathic sudden deafness. The results of the deaf ears were compared with those of the contralateral healthy ears and the normal control ears. The relations between VEMPs and the hearing level or caloric response were then investigated. RESULTS: All 20 of the deaf ears displayed normal biphasic VEMPs. The mean latencies of p13 and n23, as well as mean amplitude p13-n23, were 15.1 +/- 2.8 msec, 20.7 +/- 3.3 msec and 25.2 +/- 12.6 microV, respectively, not significantly different to either the contralateral healthy ears (p > 0.05) or the normal control ears (p > 0.05). Five deaf ears displayed canal paresis or absent caloric response, whereas the remaining 15 ears revealed normal caloric response. CONCLUSION: All the lesioned ears of patients with idiopathic sudden deafness exhibit normal biphasic VEMPs. Neither the hearing level nor the caloric response correlated to the VEMPs.     

Development of vestibular evoked myogenic potentials in preterm neonates

Our recent study successfully recorded vestibular evoked myogenic potential (VEMP) responses in full-term newborns. However, when VEMP responses are elicited in preterm neonates remains unclear. This study employed the VEMP test in 27 low-risk preterm and 25 healthy full-term neonates without sedation to investigate the development of VEMP response after birth. Fourteen (26%) of 54 ears in preterm neonates exhibited VEMP responses, a response rate significantly lower than that of full-term neonates (72%). The mean latencies of peaks p13 and n23 in the preterm group were significantly longer than those in the full-term group. Analysis of variable parameters for present VEMPs in pre- and full-term neonates revealed that the cutoff values of body weight were 2.26 and 2.82 kg, and that those of postmenstrual age were 37.1 and 38.4 weeks, respectively. Both body weight and postmenstrual age were significantly negatively correlated with p13 and n23 latencies but not with p13-n23 amplitude. In conclusion, present VEMPs can be anticipated when the body weight of pre- and full-term neonates reaches >2.26 and 2.82 kg, respectively. It indicates that the sacculocollic reflex develops in the same manner, but the difference in response rate between full- and pre-term neonates may, at least in part, correlate with muscle bulk and strength, relative to the body weight adequate for the VEMP response.     

前庭诱发肌源性电位的正常人群观察

目的:观察我国正常青年人群中前庭诱发肌源性电位(VEMP)出现的阳性率及各项参数指标。方法:选取52例(男31例,女21例)21~22岁正常健康人群,以短声为刺激声,单耳给声,同侧胸锁乳突肌(SCM)记录。结果:47例2耳均可引出VEMP,5例2耳均不能引出。总104耳中,94耳阳性,10耳阴性,阳性率90%。统计阳性耳各参数:p1潜伏期(15.97±3.22)ms、n2潜伏期(24.41±2.46)ms、p1n2间期(8.41±2.06)ms,幅值(33.27±14.37)μV,阈值(93.67±5.20)dB nHL。统计47例正常人同一个体耳内差异的各参数为p1潜伏期(0.97±1.31)ms,n2潜伏期(1.23±1.30)ms,p1n2间期(0.95±1.21)ms,幅值(10.04±11.88)μV,阈值(2.29±2.56)dB nHL。男女各参数比较差异无统计学意义。结论:绝大部分正常人可引出VEMP。VEMP的引出体现该侧耳球囊→前庭下神经→脑干前庭神经核→前庭脊髓通路→颈肌运动神经元这条反射途径的完整性。VEMP可能成为一种检测前庭终器及其传导通路完整性的方法。     

Frequency sensitivity range of the saccule to bone-conducted stimuli measured by vestibular evoked myogenic potentials

Vestibular evoked myogenic potentials (VEMPs) occurring in cervical muscles after intense sound stimulation conducted by air or bone are thought to be a polysynaptic response of otolith-vestibular nerve origin. We report the results of an experiment to investigate whether acoustic stimulation of the saccule by bone conduction produces VEMPs in which response amplitudes are somewhat sensitive to stimulus frequency, as appears to be the case with air-conducted stimuli. Prior to this we investigated the effect of stimulation repetition rate on bone-conducted VEMPs (B-VEMPs) at stimulus frequencies of 200 and 400 Hz with five different repetition rates (5, 10, 20, 40, and 80 Hz). B-VEMPs were recorded from 12 normal hearing subjects in response to bone-conducted 70 dB (normal hearing level), 10-ms tone bursts (rise/fall TIME=1 ms and plateau TIME=8 ms) at frequencies of 100, 200, 400, 800, 1600 and 3200 Hz. Our study showed that B-VEMP amplitudes were highest at 10 Hz but decreased as the repetition rate increased. B-VEMP response amplitudes were found to be maximal for stimulus frequencies from 200 to 400 Hz. This response may contribute to the perception of loud sounds.     

The effects of rise/fall time and plateau time on ocular vestibular evoked myogenic potentials

Ocular vestibular evoked myogenic potentials (oVEMP) are strongly influenced by recording conditions and stimulus parameters. Throughout the published literature, a large variety of stimuli is used for eliciting oVEMP. Our objective was to determine the effects of different rise/fall times and plateau times on oVEMP amplitudes and latencies. 32 healthy subjects were enrolled in the study. 500 Hz air-conducted tone bursts with the parameters rise–plateau–fall time 0–4–0, 4–0–4, 2–2–2 and 2–4–2 ms were used for eliciting oVEMP. For all stimuli, response prevalences were 100 %. The 4–0–4 ms stimulus generated the smallest amplitudes, whereas the 2–2–2 and 0–4–0 ms stimuli achieved the largest amplitudes. n1 and p1 latencies were significantly shorter for the 0–4–0 ms than for the other stimuli, whereas latencies in response to the 4–0–4 ms stimulus were prolonged. Hence, a variety of stimuli is suitable for evoking oVEMP in healthy subjects. We recommend a 2–2–2 ms stimulus for clinical testing of oVEMP elicited by air conducted sound, because it reproducibly generates oVEMP without exposing the ear to unnecessary amounts of acoustic energy.     

Vestibular evoked myogenic potentials in preterm infants

The goal of this study was to determine whether there was an association between perinatal risk factors of prematurity and vestibular evoked myogenic potentials (VEMPs). A prospective case-control trial was designed. Fifty preterm newborns (100 ears) with a gestational age <37 weeks were included. The control group consisted of 20 healthy term infants (40 ears). VEMP recordings were performed, and mean latencies of p13 were calculated in all study subjects. Multivariable logistic regression was used to investigate the influence of perinatal variables on abnormal VEMP responses. VEMPs were elicited in all term infants (40 ears). In preterm infants, the responses were normal in 71 ears, delayed in 24 and absent in 5. There was a significant difference between abnormal VEMP rates for preterm and term infants (p < 0.001). Asphyxia (OR = 13.985, p = 0.048) and time of VEMP test (OR = 0.865, p = 0.038) were related to abnormal VEMP responses. There was no association between delayed VEMPs and gestational age, birth weight, hemoglobin and bilirubin levels, phototherapy, intracranial hemorrhage, convulsions, sepsis, ototoxic drugs, transfusion, mechanical ventilation, retinopathy of prematurity, bronchopulmonary dysplasia and respiratory distress syndrome. These results suggest a delay in the maturation of VEMPs in premature infants. Asphyxia was the most important risk factor for abnormal VEMP responses in preterm infants.