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Objective The tests of three types of auditory evoked potentials （AEPs） were performed on normal young adults, to understand the frequency characteristics of different testing methods and the relationship between response threshold and pure tone audiometry threshold of different methods, and to discuss the forensic value of 3 types of AEPs to evaluate hearing function. Methods Twenty normal young adults were selected, their standard pure tone audiometry threshold, short-term pure tone audiometry threshold and the response threshold of 3 types of AEPs （tone burst-auditory brainstem response, 40 Hz auditory event-related potential and slow vertex response） at 0.5 kHz, 1.0 kHz, 2.0 kHz and 4.0 kHz were recorded. The relationship between the response threshold and standard pure tone audiometry threshold, short-term pure tone audiometry threshold of 3 types of AEPs at different frequencies as well as the differences between different types of AEPs were analyzed. Results The short-term pure tone audiometry threshold was higher than the standard pure tone audiometry threshold at each frequency. The response threshold and standard pure tone audiometry threshold of the 3 types of AEPs all had a certain correlation, and the response threshold of the 3 types of AEPs was higher than short-term pure tone audiometry threshold and standard pure tone audiometry threshold at each frequency. The differences in the differences between the response threshold and standard pure tone audiometry threshold of the 3 types of AEPs at different frequencies had statistical significance. Linear regression mathematical models were established to infer the standard pure tone audiometry threshold （hearing level） from response threshold （sound pressure level） of 3 types of AEPs of normal young adults. Conclusion When using response threshold of different types of AEPs to estimate pure tone audiometry threshold, conversion and correction are needed. Combined use of different types of AEPs could improve the accuracy of hearing function evaluation.
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Humanos , Adulto Jovem , Audiometria de Resposta Evocada , Audiometria de Tons Puros , Limiar Auditivo , Potenciais Evocados Auditivos , Potenciais Evocados Auditivos do Tronco Encefálico , AudiçãoRESUMO
Objective Thresholds for auditory brain stem responses (ABRs) to tone burst and tone burst in notched noises of two different intensities were tested in adults with sensorineural hearing loss.The relationship between ABR and puretone thresholds was analyzed to identify an acoustic stimuli with better frequency-specificity.Methods Thirty-eight adults with sensorineural hearing loss (totally 45 ears) were included in the study.Tone burst used to elicit ABRs had 2.5 cycles on the rise and fall and no plateau.Notched noises of two different intensities were used to mask tone burst ipsilaterally when recording ABRs.Those two kinds of notched noises were 25 dB (intensity A) and 15 dB (intensity B) lower than tone burst in intensity respectively.Tone burst ABRs without masking were named tb-ABR,while tone burst ABRs in notched noises of intensity A and B named as amtb-ABR and bmtb-ABR.Thresholds for tb ABR,amtb ABR and bmtb-ABR were tested and analyzed.Results The regression coefficients between puretone thresholds and thresholds for tb-ABR,amtb-ABR and bmtb-ABR of all frequencies were greater than 0.8.The mean differences between ABR and puretone thresholds were all less than 10 dB.Tb-ABR thresholds the were the closest to puretone thresholds at 500 Hz,while bmtb ABR thresholds were the closest at the other three frequencies.Bmtb-ABR thresholds were more close to puretone thresholds in patients with steeply sloping hearing loss.Conclusion Thresholds for all those three ABRs could be used to predict puretone thresholds.In most condition,tb-ABR thresholds were able to estimate puretone thresholds.In some condition,different stimuli could be chosen to elicit ABR at different frequencies.It was reasonable to choose bmtb -ABR for puretone thresholds estimation in patients with steeply sloping hearing loss.
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Objective To study the auditory brainstem response (ABR) of normal adult CBA,C57BL,Kunming and 129 mice and analyze the ABR thresholds and latencies in order to obtain normal values and standardized testing process,thereby providing important reference for future auditory hearing research in mouse.Methods Six -week-old normal mice of CBA,C57BL,Kunming and 129(each strain containing 20 ears of 20 mice) were used in this study.ABR test with both the click and tone burst were carried on.The incidence of each wave and the thresholds and latencies of various strains of mice were recorded.Results For these four strains of mice,wave Ⅱ had the highest occurrence rate and was used to determine the thresholds.Four strains of mice all were sensitive to the sound at 8,12,16 kHz,most to 12 kHz.Under anesthesia condition,the latency of each ABR wave prolonged as testing time increase,especially the waves Ⅲ ～ V which reflected the functions of the part near the cerebral center.Conclusion Under anesthesia state,for these four strains of mice,wave Ⅱ has the highest occurrence rate and is used to determine the threshold.We determine the intensity level at which Wave Ⅱ just appeared as the ABR threshold.The stain of CBA mice is the best one to establish an animal model related to hearing function research because ABR of the other three strains are not stable as the CBA mice.Wave SP can reflect the hair cell functions indirectly.
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Objective To study the relationship among the slow vertex response (SVR) ,tone burst ABR threshold and pure tone thresholds in young people with normal hearing ,and to discuss the values of SVR and tb -ABR assessing hearing thresholds .Methods A total of 30 normal-hearing young people aged 20 to 24 were indud-ed in this study .The thresholds of SVR ,tb -ABR and threshold of PTA were tested at each verbal frequency (0 .5 ,1 ,2 ,4 kHz) .The differences and the relationship among SVR with PTA ,tb-ABR ,and PTA were statistical-ly studied .Results The differences between SVR and tb -ABR and PTA at various frequencies were statistically significant (P<0 .05) .The minimum difference between SVR and PTA was (3 .59 ± 7 .32) dB at 0 .5 kHz .The differences of 1 ,2 ,and 4 kHz were 6 .92 ± 5 .07 ,8 .33 ± 6 .71 ,and 9 .83 ± 9 .41 dB ,respectively .The minimum differences between tb -ABR and PTA was 14 .58 ± 7 .24 dB at 4 kHz ,and the differences of 0 .5 ,1 ,and 2 kHz were 29 .42 ± 6 .83 ,23 .25 ± 7 .47 ,and 16 .50 ± 6 .43 dB ,respectively .SVR and PTA had a good correlation at 1 and 2 kHz (r=0 .51 ,P<0 .01 and r=0 .44 ,P<0 .05 ,respectively) .tb-ABR and PTA had a good correlation at 4 kHz (r=0 .53 ,P<0 .01) .Conclusion In normal hearing young population ,SVR and tb-ABR can estimate PTA well , and the former is closer to PTA threshold .
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Objective To investigate the relationships of tone burst -ABR Thresholds and the pure -tone audiograms in normal hearing adults .Methods The response thresholds of Tone burst -ABR and the pure -tone audiogram were recorded from 34 adult(68 ears) at 0 .5 ,1 .0 ,2 .0 ,and 4 .0 kHz .The results were statistically ana-lyzed .The correlation of the response thresholds of tone burst -ABR and the pure-tone audiogram were studied . Results At 0 .5 ,1 .0 ,2 .0 ,4 .0 kHz ,the averages of the response thresholds of tone burst -ABR were 27 .43 ± 3 .29 ,25 .98 ± 2 .76 ,16 .78 ± 2 .37 ,and 12 .42 ± 2 .64 dB nHL ,respectively .The averages of the pure -tone audio-gram were 12 .23 ± 3 .99 ,11 .82 ± 2 .56 ,9 .58 ± 3 .23 ,and 9 .92 ± 2 .59 dB nHL ,respectively .The differences between the response thresholds of tone burst -ABR and the pure-tone audiogram were 12 .13 ± 4 .51 ,11 .43 ± 3 .66 ,7 .61 ± 2 .43 ,and 7 .17 ± 1 .32 dB ,respectively .At 0 .5 ,1 .0 ,2 .0 ,and 4 .0 kHz ,Pearson correlation coefficients were 0 .69 ,0 .79 ,0 .84 ,0 .89 ,respectively .Conclusion The tone burst -ABR and the pure -tone audiogram thresholds were a highly correlated with each other ,especially at 2 .0 kHz and 4 .0 kHz .Tone burst -ABR has the frequency specificity ,which can response the hearing level better .
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Cervical Vestibular Evoked Myogenic Potential (cVEMP) is a routine vestibular test which checks the integrity of vestibulocollic reflex (VCR) pathway. Clinically, 500-Hz tone burst is widely used stimulus to evoke a cVEMP. Although several studies have suggested different plateau times (PT) for eliciting cVEMPs, but not many have reported the optimal PT for evoking cVEMP using 500 Hz tone burst stimuli. Therefore, the present study aimed to investigate the effect of PT on cVEMPs elicited by 500 Hz tone burst at 95 dBnHL using four different PT (0, 2, 4 and 10 ms). Thirty healthy adults with normal hearing and vestibular systems participated in this study. Results revealed that the P1 latency was significantly longer for PT 10 ms compared to other PTs. N1 latency was significantly prolonged for long PT of 10 ms compared to PT 2 ms. P2 latency showed no significant differences among PTs. The P1-N1 inter-amplitude values however revealed no significant difference across all PTs. It was found that the P1-N1 inter-amplitude was severely affected after 4 ms of PT. This study concluded that the PT of either 0 or 2 ms yielded the most robust cVEMP.
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Potenciais Evocados Miogênicos VestibularesRESUMO
Objective To investigate the click and tone burst evoked auditory brainstem responses (ABR)in normal Wistar rat,and to establish the standards of ABR testing method,and to provide a reference for studies rat audition.Methods Fifteen male Wistar rats(30 ears)were used in this sutdy.The latency and amplitude of ABR e-voked by click and TB at 80,50 and 20 dB SPL were measured.Results The occurrence rate of wave Ⅱand Ⅳat low levels(20 dB SPL)was nearly the same according to the amplitude.The cABR (dB peSPL)threshold was 21.83± 4.45 and tbABR (dB SPL)thresholds were 2.02±0.09,2.88±0.16,3.77±0.25,4.69±0.29,and 5.78±0.41, respectively.80 dB stimulus evoked cABR (peSPL)wave I,I b,II,III,IV and V latency (ms)were 1.76±0.12, 2.13±0.11,2.67±0.16,3.49±0.28,4.39±0.29,and 5.45±0.41,respectively.tbABR (SPL)of wave I,Ib, II,III,IV and V latency (ms)at 4 kHz were 2.02±0.09,2.88±0.16,3.77±0.25,4.69±0.29,and 5.78± 0.41,respectively.At 8 kHz they were 1.76±0.07,2.28±0.10,2.63±0.16,3.49±0.21,4.44±0.28,and 5.48±0.43;while at 12 kHz were1.76±0.08,2.24±0.12,2.61±0.25,3.53±0.25,4.46±0.32,and 5.52± 0.45;at 16 kHz were 1.79±0.10,2.25±0.12,2.70±0.18,3.62±0.27,4.52±0.37,and 5.61±0.49;at 24 kHz were 1.75±0.09,2.27±0.11,2.67±0.16,3.60±0.27,4.52±0.38,and 5.60±0.51;at 32 kHz were 1.77±0.10,2.24±0.12,2.64±0.20,3.59±0.34,4.52±0.40,and 5.61±0.52,respectively.Conclusion Wave Ⅳ was the best wave to determine threshold of click and tone burst evoked auditory brainstem response in rat.
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Objective To compare the accuracy of auditory brain stem response (ABR) thresholds to tone burst and tone burst ipsilaterally masked by notched noise in estimating puretone thresholds of adults with normal hearing.To study characteristics of ABRs evoked by tone burst and tone burst in notched noise of two different intensities.These three kinds of ABRs were named as follows:tb-ABR,amtb-ABR and bmtb-ABR.Methods Puretone audiometry,ABRs to tone burst and tone burst ipsilaterally masked by notched noise of different intensities were tested in 20 adults (totally 40 ears) with normal hearing.Results ①Thresholds for tb-ABR,amtb-ABR and broth-ABR of each frequency all approximated each other,and there were no statistically significant differences between them.②The mean differences between puretone thresholds and thresholds for tb-ABR,amtb -ABR and bmtb-ABR of each frequency were all less than 15 dB.Those mean differences of different ABRs of the same frequency were approximate to each other and had no statistically differences.③No matter what kind of ABR was tested,the latencies of wave V shortened with increase of frequency in each ABR at the same intensity.When the intensity and frequency of the tone burst were the same,the latency of wave V of tb-ABR was always statistically shorter than that of amtb-ABR.The latter was also always statistically shorter than that of bmtb-ABR.Conclusion Thresholds for ABRs to tone burst and tone burst ipsilaterally masked by notched noise were useful in predicting puretone thresholds.
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Objective To study the characteristic of acoustically short latency negative response (ASNR) in auditory brainstem response (ABR) evoked by tone burst in children with hearing loss. Methods ABRs to click and tone burst were recorded from 0～6 years old children with hearing loss using SmartEP auditory evoked potential system. The threshold and latency was analyzed if ASNR was recorded. Results Among all the 80 ears tested, ASNR were recorded in 7 ears (8.75%) when using click, and in 40 ears (50%) when using tone burst. ASNR was most frequently evoked by 1 kHz tone burst (in 37 ears), and 2 kHz (in 25 ears) was the second. Among the ears with ASNR, the lowest threshold of ABR wave V was 65 dB nHL. The lowest threshold of ASNR was 80dB nHL. The latencies of ASNR for 0.5,1,2 and 4 kHz tone burst was 6～8, 5～7,3～5 and 3～4 ms, respectively. The latency decreased along with the increase of intensity. Conclusion ASNR can be recorded while recording tone-burst ABR, but it has no effect in predicting hearing level using the wave V threshold of tone-burst ABR.
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BACKGROUND AND OBJECTIVES: Vestibular evoked myogenic potential (VEMP) is muscle reflex caused by surface electrodes following repeated high-intensity auditory stimulation. The current study attempted to determine whether VEMP can be consistently evoked from the sternocleidomastoid muscle (SCM) by the 100 dB air-conducted and 50 dB bone-conducted 500 Hz-tone burst. SUBJECTS AND METHOD: Air-conducted and bone-conducted VEMPs in response to 500 Hz-tone burst were recorded from the SCM of 13 normal volunteers. Subjects were seated on their chairs and made to hold their heads turned up as far as possible towards the side, contralateral to the stimulated ear voluntarily. Two different sound durations (rise/fall time=2 msec, plateau time=2 msec[2/2] and rise/fall time=5 msec, plateau time=5 msec[5/5]) were presented through a insertphone or bone vibrators. Latencies and amplitudes of p13 and n23 responses were measured. RESULTS: All normal volunteers showed p13-n23 responses to 50 dB bone-conducted tone burst as well as to 100 dB air-conducted tone burst. The values of latency of p13 and n23 were the most reliable at 5/5 air-conducted in evaluation by coefficiency of variance. Mean p13 and N23 latencies by airconducted tone burst were significantly longer than those of bone-conducted. Mean p13-n23 amplitudes by air-conducted tone burst were significantly larger than those by bone-conducted at 2/2 sound duration. CONCLUSION: VEMP could be consis-tently evoked by the 100 dB air-conducted and 50 dB bone-conducted 500 Hz-tone burst, especially at 5/5 air-conducted.