Tone Burst Stimulation Research Articles

Click SP/AP Area Ratio Vesrus Tone Burst SP Amplitude to Diagnose Ménière's Disease Using Electrocochleography.

To evaluate the sensitivity and the specificity of summating potential (SP)/action potential (AP) area under the curve (AUC) ratio by a transtympanic electrode and a click stimulus (TT-CS), SP/AP AUC ratio by an extratympanic electrode and a click stimulus (ET-CS) and SP amplitude value by a transtympanic electrode and tone burst stimulus (TT-TBS) in regard of Ménière's disease (MD) diagnosis. This is the first study that compares SP amplitude value performed by a TT-TBS and the SP/AP AUC ratio performed by a TT-CS. Retrospective comparative study. Ninety-five patients met the inclusion criteria for electrocochleography (ECochG) testing in a tertiary care center. The sensitivity and specificity of our different ECochG protocols were calculated in regardof the diagnosis of MD. The patients' mean age was 54 years old (female predominance). The sensitivity and the specificity of SP/AP area ratio by a TT-CS were 88.5% and 70.0%, respectively. On the other hand, the sensitivity and specificity for the SP amplitude value by a TT-TBS were 60.0% and 55.6%, respectively. SP/AP area ratio by TT-CS was statistically better than SP amplitude value by TT-TBS to detect MD disease (P = .016). However, no difference was identified between SP/AP area ratio by ET-CS and SP amplitude value by a TT-TBS (P = .573). SP/AP area ratio by click stimulation has higher sensitivity and specificity to detect MD compared to SP amplitude value by tone burst stimulation. ECochG would be extremely useful in the diagnosis of MD if we use the SP/AP area ratio (sensitivity: 88.5%); therefore, it changes the bad reputation of ECochG sensitivity using SP/AP amplitude ratio (sensitivity: 51.7%) for the diagnosis of MD.

Vestibulospinal reflexes elicited with a tone burst method are dependent on spatial orientation.

Balance involves several sensory modalities including vision, proprioception and the vestibular system. This study aims to investigate vestibulospinal activation elicited by tone burst stimulation in various muscles and how head position influences these responses. We recorded electromyogram (EMG) responses in different muscles (sternocleidomastoid-SCM, cervical erector spinae-ES-C, lumbar erector spinae-ES-L, gastrocnemius-G, and tibialis anterior-TA) of healthy participants using tone burst stimulation applied to the vestibular system. We also evaluated how head position affected the responses. Tone burst stimulation elicited reproducible vestibulospinal reflexes in the SCM and ES-C muscles, while responses in the distal muscles (ES-L, G, and TA) were less consistent among participants. The magnitude and polarity of the responses were influenced by the head position relative to the cervical spine. When the head was rotated or tilted, the polarity of the vestibulospinal responses changed, indicating the integration of vestibular and proprioceptive inputs in generating these reflexes. Overall, our study provides valuable insights into the complexity of vestibulospinal reflexes and their modulation by head position. However, the high variability in responses in some muscles limits their clinical application. These findings may have implications for future research in understanding vestibular function and its role in posture and movement control.

Comparison of Compressed High-Intensity Radar Pulse and Tone Burst Stimulation in Vestibular Evoked Myogenic Potentials in Acute Peripheral Vestibular System Pathologies.

It is ascertained that the compressed high-intensity radar pulse (CHIRP) is an effective stimulus in auditory electrophysiology. This study aims to investigate whether Narrow Band Level Specific Claus Elberling Compressed High-Intensity Radar Pulse (NB LS CE-CHIRP) stimulus is an effective stimulus in the vestibular evoked myogenic potentials test. A case-control study was designed. Fifty-four healthy participants with no vertigo complaints and 50 patients diagnosed with acute peripheral vestibular pathology were enrolled in this study. Cervical and ocular vestibular evoked myogenic potential tests (cervical vestibular evoked myogenic potentials and ocular vestibular evoked myogenic potentials) with 500 Hz tone burst and 500 Hz Narrow Band Level Specific CE-CHIRP stimulations were performed on all participants. In addition, cervical vestibular evoked myogenic potentials and ocular vestibular evoked myogenic potentials tests with 1000 Hz tone burst and 1000 Hz Narrow Band Level Specific CE-CHIRP were performed on 24 Meniere's disease patients. P1 latency, N1 latency, amplitude, threshold, and the asymmetry ratio of responses were recorded. In healthy participants, with CHIRP stimulus, shorter P1 latency (P < .001), shorter N1 latency (P < .001), and lower threshold (P = .003) were obtained in the cervical vestibular evoked myogenic potentials test; shorter P1 latency (P < .001), shorter N1 latency (P < .001), higher amplitude (P < .001), and lower threshold (P < .001) were obtained in ocular vestibular evoked myogenic potentials test. In symptomatic ears of patients, with CHIRP stimulus, shorter P1 latency (P < .001), shorter N1 latency (P < .001), and lower threshold (P=.013 in cervical vestibular evoked myogenic potentials; P=.015 in ocular vestibular evoked myogenic potentials) were obtained in cervical vestibular evoked myogenic potentials and ocular vestibular evoked myogenic potentials tests. In asymptomatic ears of patients, with CHIRP stimulus, shorter P1 latency (P < .001) and shorter N1 latency (P < .001) were obtained in the cervical vestibular evoked myogenic potentials test; shorter P1 latency (P < .001), shorter N1 latency (P < .001), higher amplitude (P < .001), and lower threshold (P=.006) were obtained in ocular vestibular evoked myogenic potentials test. Our results suggest that due to higher response rates, shorter latencies, higher amplitude, and lower threshold values, the Narrow Band Level Specific CE-CHIRP stimulus is an effective stimulus for both cervical vestibular evoked myogenic potentials and ocular vestibular evoked myogenic potentials tests.

Cervical and ocular vestibular evoked myogenic potential: A comparison of narrowband chirp, broadband chirp, tone burst and click stimulation

Objectives To compare the response rate and response parameters of cervical and ocular vestibular evoked myogenic potentials (c&oVEMP) elicited by narrowband (NB) and broadband (BB) CE-Chirp, with the more classical tone burst (TB) and click VEMPs. Design The response rate, latency, amplitude and asymmetry ratio of c&oVEMPs elicited by 95 dB nHL air conducted (AC) 500 Hz NB CE-chirp, BB CE-chirp, 500 Hz TB and click stimuli were recorded bilaterally. Study sample 20 male and 38 female participants (19–39 years). Results For the cVEMP, the highest response rate was found for NB chirp (100%), followed by TB (91%), BB chirp (87%) and finally click (85%). A similar order was seen for oVEMP with percentages of 100%; 57%, 57%, and 43%. The 500 Hz NB CE-Chirp elicited significantly shorter cVEMP P1 and N1 latencies and significantly larger c&oVEMP amplitudes compared to all other stimuli. BB CE-Chirp elicited significantly shorter c&oVEMP P1 and N1 latencies with smaller amplitudes compared to TB. Asymmetry ratios were not statistically significant for all comparisons. Conclusion The 500 Hz NB CE-chirp provides the highest response rates, shorter latencies and larger amplitudes, and therefore seem a promising stimulus for reliably measuring c&oVEMPs in clinical practice.

Comparison of cervical and ocular vestibular-evoked myogenic potential responses between tone burst versus chirp stimulation.

To compare the effectiveness of chirp and tone burst stimuli in oVEMP and cVEMP testing for healthy adults METHODS: This study was conducted in 56 healthy volunteers (112 ears). Ocular and cervical VEMP (oVEMP, cVEMP) tests were performed for each participant using tone burst and chirp stimuli. VEMP response rates, latency of each peak (p1-n1, n1-p1), peak to peak amplitude (p1-n1 amplitude and n1-p1 amplitude), and rectified amplitudes were measured and compared between these two different stimuli. VEMP response rates with chirp stimuli are higher than the tone burst stimuli for both cVEMP and oVEMP tests (The difference was statistically significant for oVEMP, p = 0.001). Chirp stimuli have higher p1n1 amplitude and rectified amplitude and shorter p1and n1 latency then tone burst stimuli for cVEMP (p = 0.015, p = 0.007, p < 0.001, p < 0.001, respectively). Chirp stimuli also have higher n1p1 amplitude and shorter n1and p1 latency then tone burst stimuli for oVEMP (p = 0.006, p < 0.001, p < 0.001, respectively). The present findings show that the chirp stimulus triggers earlier VEMP responses with higher amplitudes than the tone burst stimulus during cVEMP and oVEMP testing. VEMP response rate with chirp stimulus is also higher than the tone burst. Therefore chirp stimulus can be used in VEMP testing as effectively as, if not more than, tone burst stimulus in clinical practice.

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.

Correction: Effects of Spirulina on the functions and redox status of auditory system in senescence-accelerated prone-8 mice.

[This corrects the article DOI: 10.1371/journal.pone.0178916.].

Effects of Spirulina on the functions and redox status of auditory system in senescence-accelerated prone-8 mice.

To our knowledge, the effects of Spirulina platensis water extract (SP) on hearing function have not yet been reported. This study investigated the effects of SP on the function and redox status of the auditory system. Auditory brainstem responses and redox status were compared between two groups of 3-month-old senescence-accelerated prone-8 (SAMP8) mice: the control group was fed a normal diet, and the experimental group was fed a normal diet with oral supplementation of SP for 6 weeks. Compared with the control group, the experimental group had significantly lower hearing thresholds according to auditory brainstem responses measured using click sounds and 8-kHz tone burst sound stimulation at the end of this study. The experimental group had a shorter I-III interval of auditory brainstem responses with 16-kHz tone burst stimulation than the control group that was of borderline significance. Additionally, the experimental group had significantly higher mRNA expression of the superoxide dismutase and catalase genes in the cochlea and brainstem and significantly higher mRNA expression of the glutathione peroxidase gene in the cochlea. Further, the experimental group had significantly lower malondialdehyde levels in the cochlea and brainstem than the control group. However, tumor necrosis factor–α mRNA expression was not significantly different between the control and experimental groups. SP could decrease hearing degeneration in senescence-accelerated prone-8 mice possibly by increasing superoxide dismutase, catalase, and glutathione peroxidase gene expression and decreasing damage from oxidative stress in the cochlea and brainstem.

Diagnostic value of vestibular-evoked myogenic potentials in Ménière's disease and vestibular migraine.

Overlaps can be seen between vestibular migraine (VM) Ménière's Disease (MD) and diagnosis is difficult if hearing is normal. We aimed to investigate the sacculo-collic pathway in VM patients, MD patients, and healthy controls to define the diagnostic role of cervical VEMP (cVEMP). VEMP testing in response to 500 Hz and 1000 Hz air-conducted tone burst (TB) stimulation was studied prospectively in 22 subjects with definite VM (according to Bárány nomenclature), 30 subjects with unilateral definite MD, and 18 volunteers matched healthy controls. In VM subjects, response rate, p13 and n23 latencies were similar to healthy controls, but peak-to-peak amplitudes were bilaterally reduced at 500 Hz TBs (p= 0.005). cVEMP differentiated MD patients from VM and healthy controls with asymmetrically reduced amplitudes on affected ears with low response rates at 500 Hz TBs, and alteration of frequency dependent responses at 500 and 1000 Hz TBs. These findings suggest that cVEMP can be used as a diagnostic test to differentiate MD from VM. On the other hand, VEMP responses are symmetrically reduced on both sides in VM patients, suggesting that otolith organs might be affected by migraine-induced ischemia.

Video Head Impulse Test, 温度刺激検査, VEMP を用いた前庭神経炎の障害部位の検討

The aim of this study was to classify unilateral vestibular neuritis (VN) with caloric testing, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and the video head impulse test (vHIT). Eight Patients (3 males and 5 females, mean age 55.6 years) with VN were studied. cVEMP and oVEMP (105 dBSPL 500 Hz short tone burst stimulation) were recorded. The caloric test and vHIT for the 3 semicircular canal were performed. The caloric test, cVEMP and oVEMP in combination with vHIT were able to allow the classification of 4 types of VN: entire VN, superior VN, inferior VN, and ampullary VN. In our case, 75% of the cases were entire VN, 12.5% were superior VN, and 12.5% were inferior VN. Three patients had only deficits of the horizontal and/or inferior semicircular canals or their ampullary nerves. One of eight VN patients had symptoms similar to benign paroxysmal positional vertigo after three weeks onset of VN. The results lead us to believe that clinical VN comprises vestibular neuritis and vestibular labyrinthitis. Currently, in Japan it would be essential that there is canal paresis in caloric test for VN diagnosis. We hope to include inferior VN within the diagnosis criteria of VN in the near future.

The diagnostic value of vestibular evoked myogenic potentials in patients with Meniere's disease

To estimate the sensitivity and specificity of vestibular evoked myogenic potentials (VEMPs) in comparison with caloric test in diagnosing Meniere's disease (MD) among patients with dizziness. Data were retrospectively collected from 1,170 consecutive patients who underwent vestibular tests. Among them, 114 patients were diagnosed as having unilateral definite MD. VEMPs in response to clicks and short tone burst stimulation as well as caloric tests were performed. The sensitivity and specificity of each test were evaluated. The results of each test were compared with hearing level and staging of MD. The sensitivity and specificity of VEMPs were 50.0% and 48.9%, while those of the caloric test were 37.7% and 51.2%, respectively. There was no significant difference in hearing level between patients appropriately or inappropriately identified by VEMPs, whereas there was a significant difference in those of the caloric test. Combined use of VEMP and caloric test increased the sensitivity to 65.8%. Although the sensitivity and specificity of VEMPs in diagnosing MD were not high, they were comparable to those of caloric test. VEMPs as well as caloric testing may give additional information as part of a diagnostic test battery for detecting vestibular abnormalities in MD.

Ocular Vestibular Evoked Myogenic Potential to Air Conducted Sound Stimulation and Video Head Impulse Test in Acute Vestibular Neuritis

Air-conducted (ACS) cervical VEMP (cVEMP) reflect both saccular and inferior vestibular nerve function. Ocular VEMP (oVEMP) to air and bone-conducted vibration (BCV) are critically discussed, whether they reflect predominantly utricular and superior vestibular nerve function. The video head impulse test (vHIT) accurately detects changes in the high frequency range (5-7 Hz) of the vestibular ocular reflex (VOR) in all 3 planes and can be used to assess semicircular canals (SCC) impairment. To evaluate oVEMP and cVEMP in response to 500 Hz ACS stimulation and to compare these with vHIT results in acute unilateral vestibular neuritis (VN) to classify the probable involvement of SCC and otolith organs. Patients with VN were studied. ACS oVEMP and ACS cVEMP (100 dB nHL 500 Hz tone burst stimulation) were recorded. The vHIT for the 3 SCC were performed simultaneously. ACS oVEMP and ACS cVEMP in combination with vHIT allows the differentiation of 4 types of VN: entire VN (EVN), superior VN (SVN), inferior VN (IVN), and ampullary VN (AVN). Lesions of EVN, SVN, and IVN may be either complete or partial. ACS oVEMP and ACS cVEMP to 500 Hz stimulation together with the vHIT allows a better differentiation of receptor involvement in VN. Results suggest a different origin of AC oVEMP and AC cVEMP to 500 Hz in complete SVN and IVN. Partial SVN and IVN may indicate a role of saccular fibers in oVEMP.

Effectiveness of different click stimuli in diagnosing superior canal dehiscence using cervical vestibular evoked myogenic potentials

Conclusion: Testing cervical vestibular evoked myogenic potential (cVEMP) in response to 90 dB nHL clicks can, in contrast to high-intensity 500 Hz tone bursts, be used as a screening test for superior canal dehiscence (SCD) syndrome. Objectives: cVEMP testing has its key clinical significance for evaluating saccular and inferior vestibular nerve function, but also for assessment of vestibular hypersensitivity to sounds in patients with SCD syndrome. The routine stimulus used in cVEMP testing is high-intensity 500 Hz tone bursts. The aim of the present study was to compare the high-intensity tone burst stimulation with less intense click stimulations for the diagnosis of SCD syndrome. Methods: cVEMP amplitudes in response to 500 Hz tone bursts and clicks were studied in 38 patients with SCD syndrome unilaterally. Results: cVEMP testing using high-intensity 500 Hz tone bursts did not consistently distinguish SCD patients. This nonfunctioning of high-intensity 500 Hz stimulation is most likely due to saturation. With 90 and 80 dB nHL clicks there is low risk for saturation and both these click stimulations were effective. Testing with both 80 and 90 dB nHL clicks did not have any significant advantage over just using 90 nHL dB clicks.

Effects of a zinc-deficient diet on hearing in CBA mice

This study investigated the effect of a zinc-deficient diet on the hearing in CBA mice and aimed to verify whether this hearing change is reversible by supplementation of zinc afterwards. We assessed hearing through an auditory brainstem response (ABR) with tone burst stimulation in 4, 8, 16, and 32 kHz and distortion product otoacoustic emissions in 5.6, 8, 11.3, and 16 kHz every week. The ABR threshold started to increase after 4 weeks on a zinc-deficient diet. The difference in the threshold between control and zinc-deficient animals became greater over time and plateaued at about 6 weeks. The ABR threshold differences between control and zinc-deficient mice were greater at higher frequencies. Four weeks of normal diet, following 8 weeks of a zinc-deficient diet, restored the ABR threshold to normal at all measured frequencies. Zinc-deficient mice did not show any distortion product otoacoustic emission threshold change at all frequencies. This finding suggests that a zinc-deficient diet increased the ABR threshold in CBA mice and a zinc-adequate diet restored the ABR threshold to normal.

Comparison of tone burst versus logon stimulation for vestibular evoked myogenic potentials

The following study has been carried out to compare the effectiveness of logon and tone burst acoustic stimulation to elicit vestibular evoked myogenic potential (VEMP) responses. The methods and the subjects include 31 healthy adult volunteers (62 ears) who were enrolled in this study. Two different acoustic stimuli, logon (L-VEMP) and tone burst (T-VEMP), were used to elicit VEMP responses in each subject. Bilateral recordings with simultaneous binaural acoustic stimulations were used during VEMP recordings. During the recording period, the subjects were in supine position with their head elevated. The results observed were that the response rate of p1n1 wave was 91.9% for L-VEMP and 88.7% for T-VEMP. The response rate of n2p2 wave was 80.6% for L-VEMP, and 75.8% for T-VEMP. There were no significant differences between the two groups with respect to the latencies of p1, n1, n2 and p2, p1n1 and n2p2 interval, and p1n1 and n2p2 amplitude. The conclusion was that there was no difference between logon and tone burst stimulation with respect to VEMP response rates and VEMP parameters. Therefore, they are not superior to each other.

Effects of Cigarette Smoking on Hearing Recovery From Noise-Induced Temporary Hearing Threshold Shifts in Mice

Cigarette smoking may potentiate noise-induced hearing loss. Many epidemiological studies have shown that cigarette smoking is a major risk factor for noise-induced hearing loss. BALB/c mice were exposed to passive smoking for 2 h/d for 2 weeks before exposure to 110-dB sound pressure level white noise for 3 hours once. Hearing was assessed via the auditory brainstem response with tone-burst stimulation and distortion product otoacoustic emissions before and at 1, 3, 5, 7, 14, 21, and 28 days after noise exposure. Oxidative stress and hypoxia were assessed by immunostaining with 8-oxoG and hypoxia-inducible factor 1α, respectively. Control mice unexposed to both smoking and noise and mice exposed to smoking only showed no shift in hearing threshold. In contrast, mice exposed to noise only or smoking plus noise showed abrupt increases in hearing threshold. In mice exposed to noise only, hearing threshold returned to prenoise levels after 2 weeks. However, in mice exposed to smoking plus noise, the loss of hearing was significantly higher, and hearing threshold did not return to the pre-exposure levels until 4 weeks later. Positive staining with 8-oxoG and hypoxia-inducible factor 1α were observed in the inner ear of the smoking-only and smoking-plus-noise group similar to noise-only mice, whereas no positive staining was observed in control group. These results indicate that cigarette smoking may potentiate the harmful effects of noise on hearing and disturb the recovery mechanism in the cochlea.

Low‐voltage activated Kv1.1 subunits are crucial for the processing of sound source location in the lateral superior olive in mice

Voltage-gated potassium (Kv) channels containing Kv1.1 subunits are strongly expressed in neurons that fire temporally precise action potentials (APs). In the auditory system, AP timing is used to localize sound sources by integrating interaural differences in time (ITD) and intensity (IID) using sound arriving at both cochleae. In mammals, the first nucleus to encode IIDs is the lateral superior olive (LSO), which integrates excitation from the ipsilateral ventral cochlear nucleus and contralateral inhibition mediated via the medial nucleus of the trapezoid body. Previously we reported that neurons in this pathway show reduced firing rates, longer latencies and increased jitter in Kv1.1 knockout (Kcna1−/−) mice. Here, we investigate whether these differences have direct impact on IID processing by LSO neurons. Single-unit recordings were made from LSO neurons of wild-type (Kcna1+/+) and from Kcna1−/− mice. IID functions were measured to evaluate genotype-specific changes in integrating excitatory and inhibitory inputs. In Kcna1+/+ mice, IID sensitivity ranged from +27 dB (excitatory ear more intense) to −20 dB (inhibitory ear more intense), thus covering the physiologically relevant range of IIDs. However, the distribution of IID functions in Kcna1−/− mice was skewed towards positive IIDs, favouring ipsilateral sound positions. Our computational model revealed that the reduced performance of IID encoding in the LSO of Kcna1−/− mice is mainly caused by a decrease in temporal fidelity along the inhibitory pathway. These results imply a fundamental role for Kv1.1 in temporal integration of excitation and inhibition during sound source localization.

Elicitation of mismatch negativity and its influence from stimuli deviant in the healthy youth

To work out the elicitation plan, obtain the mismatch negativity (MMN) and get out the laboratory normal value as well as to study the influence to MMN from the deviation of auditory stimuli. Hearing test of the tone burst stimulation was performed on 21 healthy young volunteers according to oddball stimulation sequence. Each subject was performed two kinds of auditory stimuli including frequency deviant stimuli and intensity deviant stimuli, and of each one included three series of stimulation. MMN was gained by subtracting the ERP of deviant stimuli from the ERP of standard stimuli. The latency and amplitude of each MMN were recorded, and then the effect of the deviant extent for MMN was analyzed. By this setup the MMN of normal young people was recorded and normal value of latency and amplitude of MMN were got. In the group of frequency deviant stimuli, the MMN latency [(155.81 +/- 29.08) ms], if the frequency was up to 2000 Hz, was shorter than that when the frequency deviance was 1000 Hz [(182.89 +/- 45.85) ms, (183.32 +/- 43.33) ms] (P = 0.033, 0.030); when the deviant extent were the same, the latency had no obvious difference if changing the frequency of the standard and deviant stimuli (P = 0.973); the MMN amplitude of three groups [(3.85 +/- 2.22) microV, (2.90 +/- 2.05) microV, (2.66 +/- 2.12) microV] had no obvious difference among them (P > 0.05). In the group of intensity deviant stimuli, the MMN latency [(157.04 +/- 34.87) ms], if the frequency was up to 20 dB, was shorter (P = 0.025, 0.017) than that when the intensity deviance was 10 dB [(184.46 +/- 38.05) ms, (186.24 +/- 42.36) ms]. When the deviant extent were the same, the latency had no obvious difference (P = 0.882) if changing the intensity of the standard and deviant stimuli but only group 4 and group 6 [(3.41 +/- 1.64) microV, (2.37 +/- 1.47) microV] were different in evidence (P = 0.031) while the others had no obvious difference (P = 0.524, 0.122). MMN was only related to the difference between standard stimuli and deviant stimuli, but there was no relationship between MMN and the notice, which indicate that MMN could objectively reflect the capability of brain to detect the change of stimuli. MMN is the representation of brain high-level sensory function.

Vestibular evoked myogenic potentials in chronic otitis media before and after surgery

Conclusion. The pathology of chronic otitis media (COM) could delay and reduce the energy transfer of sound to the inner ear. The significant improvement of postoperative vestibular evoked myogenic potential (VEMP) response rate and p13 latencies in the group of patients with no or negative postoperative ABG gain provided evidence that the sound energy inducing a VEMP might be different from the energy producing the auditory perception. Objective. To evaluate the VEMP in patients with COM before and after surgery. Subjects and methods. Twenty-four subjects with unilateral COM were enrolled. A pure tone audiogram and VEMP using 500 Hz unilateral short tone-burst stimulations were recorded before and 3 months after surgery. The postoperative VEMP responses were compared with the responses before surgery and the healthy controls. Results. After surgery, the 500 Hz air–bone gap (ABG) decreased significantly and the VEMP response rate increased significantly from 41.7% to 66.7% (p<0.05, bi-test). However, both the preoperative and postoperative p13 latencies were significantly longer than those of the healthy controls (p<0.05, Wilcoxon rank-sum test). In the 18 patients whose 500 Hz ABG did not improve with surgery, the p13 latencies were significantly shorter postoperatively (p<0.05, sign test), and the response rate also improved significantly from 44.4% (8/18) to 77.8% (14/18) (p<0.05, bi-test).

Ocular vestibular-evoked myogenic potentials elicited from monaural versus binaural acoustic stimulations

This study compared the ocular vestibular-evoked myogenic potentials (oVEMPs) that are elicited (recorded) in response to monaural and separately, simultaneous binaural acoustic stimulations. The optimal stimulation mode for oVEMPs was also determined. Twenty healthy volunteers (14 men and 6 women, aged from 22 to 33 years, mean 28 years) without any previous ear disorders were enrolled in this study. Each subject underwent oVEMP testing using monaural acoustic stimulation (Mon-oVEMP) with different stimulus intensities, and with bilateral recording. On another day, the same volunteers underwent oVEMP testing using simultaneous binaural acoustic stimulation and bilateral recording (Bin-oVEMP). With 95 dB nHL tone burst stimulation, the biphasic nI-pI waveforms were recorded with maximal amplitudes from the electrodes located below the eyes contralateral to the side of acoustic stimulation while the subject was gazing upward. Significant correlations were identified between Mon-oVEMPs and Bin-oVEMPs with respect to threshold, latencies and amplitude. However, no significant difference existed between Mon-oVEMPs and Bin-oVEMPs in terms of the response rate, threshold, latency or amplitude. The Bin-oVEMP test yields the same information as the Mon-oVEMP test, but the duration of recording in the former is shorter than the latter. The Bin-oVEMP test may be a more convenient screening tool for evaluating the crossed vestibulo-ocular reflex.