Vestibular Evoked Myogenic Potentials in Patients with Spinocerebellar Degeneration

To estimate vestibulo-collic reflexes in patients with spinocerebellar degeneration (SCD), vestibular evoked myogenic potentials (VEMPs) were recorded in 16 patients with SCD and in 9 normal subjects. The patients with SCD were classified into three groups: those with olivo-ponto-cerebellar ataxia (OPCA; n=10); those with cortical cerebellar atrophy (CCA; n=3); and those with Machado-Joseph disease (MJD; n=3). While all of the patients with OPCA and CCA showed biphasic responses (p13-n23), 2 of the 3 patients with MJD showed abnormal VEMPs bilaterally. Three sides in these 2 patients showed an absence of VEMPs, and one side showed a remarkably delayed p13. These two patients showed little response in caloric tests. These results suggest that the vestibulo-collic reflex as well as the vestibulo-ocular reflex could be damaged in MJD patients but preserved in OPCA and CCA patients.     

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.     

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 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 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.     

Personal experiences with vestibular evoked myogenic potentials as a modern method of diagnosing vestibular organ lesion and monitoring treatment

Vestibular evoked myogenic potentials (VEMPs) appear to represent a new and promising technique for the assessment of vestibulospinal reflex function. The primary aims of the study described in this article were (1) to record VEMPs in normal volunteers using available equipment and to establish a range of norms of VEMP parameter values (latency, amplitude); (2) to confirm the saccular origin of VEMPs; (3) to assess the diagnostic significance of VEMPs; and (4) to evaluate the usefulness of VEMPs in monitoring therapeutic results. The study population consisted of 252 patients representing various diagnoses of hearing loss and vestibular organ lesion. Twenty-three patients were treated with an antihomotoxic remedy, and some received placebo. The results of this study demonstrated that VEMPs are helpful in evaluating the physiological and pathological equilibrium system and in monitoring reflex reactions after treatment.     

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.     

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.     

VEMP recording by binaural simultaneous stimulation in subjects with vestibulo-cochlear disorders

To reduce the testing time of vestibular evoked myogenic potentials (VEMP) and the physical efforts of subjects, we studied if VEMP recording by binaural simultaneous stimulation in patients with vestibulo-cochlear disorders can be applicable as a screening test. Twenty-eight patients with vestibulo-cochlear disorders (12 men and 16 women, 22 to 77 years of age) were enrolled in this study. Patients were presented with binaural or monaural click (95 dBnHL) stimulation to record VEMPs. Their VEMP responses to binaural simultaneous stimulation were compared with those of monaural individual stimulation. Twenty-six of the 28 patients (93%) showed the same results in binaural simultaneous stimulation as in monaural individual stimulation. Amplitudes of p13-n23 to binaural simultaneous stimulation showed significant correlation to those of monaural individual stimulation ( r =0.774, P <0.0001 t -test). Peak latencies of p13 and n23 of binaural simultaneous stimulation also showed significant correlation to those of monaural individual stimulation (p13: r =0.684, P <0.0001 t -test, n23: r =0.657, P <0.0001 t -test). The binaural simultaneous stimulation method for VEMP recording is applicable for patients with vestibulo-cochlear disorders as a screening test in the clinic.     

Effect of head position on vestibular evoked myogenic potentials with toneburst stimuli

CONCLUSION: The present study demonstrated the robustness of VEMP testing with toneburst stimuli, since it is hardly affected by head position, i.e. base or tonic excitation levels of the saccule and inferior vestibular nerve. However, the small but highly significant difference found in latency should not be neglected: the gravitational axis in the upright position may have some special effect on tonic excitation of the saccule. OBJECTIVES: To evaluate the effect of head positions on vestibular evoked myogenic potentials (VEMPs) with toneburst stimuli. MATERIALS AND METHODS: VEMPs were recorded with short tonebursts of 500 Hz in 14 normal subjects in 5 head positions (upright, nose up, ear up, nose down, and ear down). The three parameters analyzed were: 1) latency of p13, 2) latency of n23, and 3) corrected amplitude of p13-n23 (CA p13-n23). RESULTS: One-way repeated measures ANOVA showed significant effects on both p13 (p=0.0245) and n23 (p<0.0001) latencies, but not on CA p13-n23. Bonferroni's post hoc test demonstrated that there were significant differences in n23 latency between the upright position and all other head positions leaning on the bed.     

Vestibular evoked myogenic potentials evoked by multichannel cochlear implant - influence of C levels

CONCLUSIONS: This study showed that vestibular evoked myogenic potentials (VEMPs) evoked by cochlear implant (CI), could be related to the comfortable level (C level), particularly in the channels that are closer to the apical turn of the cochlea. OBJECTIVE: The purpose of this study was to investigate the correlation between VEMPs and C level of each channel. SUBJECTS AND METHODS: We investigated 24 children who underwent cochlear implantation. VEMPs were recorded from the operated ears with the CI switched 'off' or 'on'. To investigate the correlation between VEMPs and C level, we selected 13 patients with Nucleus 24 (SPrint), and divided them into group A (normal VEMPs) and B (absence of VEMPs). In these children, all the 22 electrodes were active, and were mapped in the same frequency range for each channel. RESULTS: Twenty children (83%) showed no VEMPs with the CI 'off'. Among them, 10 elicited VEMPs with the CI 'on', but the other 10 did not. In all channels, the mean C levels of CI were higher in group A than in group B. The p values in channels 1-12 were >0.10, in channels 13-16 were 0.06-0.09, and in channels 17-22 were 0.05-0.06, which were lower but not statistically significant.     

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.     

Side-difference of vestibular evoked myogenic potentials in healthy subjects

The aim of this study was to investigate the side-difference of vestibular evoked myogenic potentials (VEMPs) in relation to the provocation rates, latencies and amplitudes using binaural acoustic stimulation with bilateral recording. Fourteen healthy volunteers underwent a serial VEMP testings elicited binaurally by a sequence of alternating stimulus intensities, that is, 95-95 (right-left), 85-95, 95-85, and 85-85 dBHL tone burst, respectively. The provocation rates as well as the mean latencies of p13 and n23 for the VEMPs demonstrated no significant side-difference despite using 95-95, 85-95, 95-85 and 85-85 dBHL binaural acoustic stimulation. In contrast, nine (64%) of the 14 subjects showed side-difference of absolute p13-n23 amplitude, including right side dominant in five subjects, and left side dominant in four subjects. However, there was no significant side-difference in terms of relative amplitude despite using 95-95, 85-95, 95-85 and 85-85 dBHL binaural acoustic stimulation. Furthermore, the relative amplitude or interaural amplitude difference (IAD) ratios between those with and without side-difference of p13-n23 amplitude did not differ significantly. Hence, this study provides a potentially important method for adjusting the side difference of p13-n23 amplitudes by using a relative amplitude or IAD ratio adjustment. It also adds confidence to the successful use of binaural stimulation and recording of VEMPs under conditions of bilateral SCM muscular contractions.     

Vestibular evoked myogenic potentials induced by intraoperative electrical stimulation of the human inferior vestibular nerve

Vestibular evoked myogenic potentials (VEMPs) can be recorded from sternocleidomastoid muscle (SCM) in clinical practice. The aim of the present study was to investigate VEMPs upon direct electrical stimulation of the human inferior vestibular nerve to evidence the vestibulocollic reflex arch and their saccular origin, respectively. Seven subjects were stimulated at the inferior (IVN) and superior (SVN) vestibular nerve. The EMG signals of the SCM were recorded. These recordings were compared to air- and bone-conduction evoked VEMPs with respect to latency and shape. All subjects showed normal VEMPs upon acoustic stimulation with a latency of 12.8+/-1.4 ms for P13, and 22.7+/-2.0 ms for the N23 pre-operatively. Upon direct electrical stimulation of the IVN, the mean latency of the positive peak was 9.1+/-2.2 and 13.2+/-2.3 ms for the negative one. No contralateral SCM response was found. Electrical stimulation of the SVN did not result in any EMG response of the SCM. The study shows experimental evidence of the vestibulocollic reflex by direct electrical stimulation of the human IVN for the first time. The method can be utilized to map VIIIth nerve subdivisions and to intraoperatively monitor IVN integrity in a real-time mode.     

Effect of head position on vestibular evoked myogenic potentials with toneburst stimuli

Conclusion. The present study demonstrated the robustness of VEMP testing with toneburst stimuli, since it is hardly affected by head position, i.e. base or tonic excitation levels of the saccule and inferior vestibular nerve. However, the small but highly significant difference found in latency should not be neglected: the gravitational axis in the upright position may have some special effect on tonic excitation of the saccule. Objectives. To evaluate the effect of head positions on vestibular evoked myogenic potentials (VEMPs) with toneburst stimuli. Materials and methods. VEMPs were recorded with short tonebursts of 500 Hz in 14 normal subjects in 5 head positions (upright, nose up, ear up, nose down, and ear down). The three parameters analyzed were: 1) latency of p13, 2) latency of n23, and 3) corrected amplitude of p13-n23 (CA p13-n23). Results. One-way repeated measures ANOVA showed significant effects on both p13 (p=0.0245) and n23 (p<0.0001) latencies, but not on CA p13-n23. Bonferroni's post hoc test demonstrated that there were significant differences in n23 latency between the upright position and all other head positions leaning on the bed.     

早期梅尼埃病患者前庭诱发肌源性电位的特征

目的 建立听力室前庭诱发肌源性电位（VEMPs）潜伏期、耳间潜伏期差值、振幅比及耳间不对称率等参数的正常值,分析早期梅尼埃病患者的VEMPs特征。方法 随机选取听力正常的健康成人39例,用于建立VEMPs正常值范围并用作健康对照;对单侧发病的早期梅尼埃病患者37例,行双侧VEMPs检测,分析其VEMPs特征。结果 37例单侧发病的早期梅尼埃病患者中,患侧未能引出者11例,双侧未能引出者4例,另外15例患侧VEMPs的异常表现可为p13或n23潜伏期延长、耳间潜伏期差值延长、振幅增强或减弱等,总异常率为81.08%。结论 当VEMPs的耳间潜伏期差值表现为延长、振幅表现为增强或减弱时,对早期梅尼埃病的诊断有显著意义。     

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).     

Effect of conductive hearing loss on the vestibulo-collic reflex

The vestibulo-collic reflex represents a promising test for evaluating the integrity of otolith function. We have investigated the threshold of this response in a group of normal subjects, and the effect of a conductive hearing loss. A positive response was recorded in 31 of 32 normal subjects. The threshold of the vestibulo-collic reflex varied from 80 to 97 dBHL in these subjects with a 95% response rate at a threshold at96 dBHL. A total of 23 ears with a conductive hearing loss in 17 patients were also investigated. The average conductive hearing loss (at 0.5, 1, 2 and 4 kHz) ranged from 8.75 to 40 dBHL (average24.46 dBHL). A positive response was recorded in only two ears. Therefore, the vestibulo-collic reflex has a high stimulus threshold which is dependant on reliable transmission of the click stimulus to the inner ear thus limiting is clinical use.     

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.