Objective To explore the effect of acupuncture at ＂Jing Jiaji＂ （颈夹背） on sudden hearing loss by observing the changes of the threshold of auditory brainstem response （ABR） of deaf guinea pigs. Methods Sixty he...Objective To explore the effect of acupuncture at ＂Jing Jiaji＂ （颈夹背） on sudden hearing loss by observing the changes of the threshold of auditory brainstem response （ABR） of deaf guinea pigs. Methods Sixty healthy guinea pigs were selected, with computer randomization, 20 were randomly divided into a normal control group （group A）, while the rest were randomly and equally divided into a model group （group B） and an acupuncture group （group C） when turned deaf after gentamycin sulfate and furosemide were administered. No treatment was administered for either the group A or the group B, while acupuncture at ＂Jing Jiaji＂ was given for the group C for 30 days. The ABR thresholds of each group were observed and recorded separately after the treatment for 15 days and 30 days. Results The ABR threshold in the group C was lower than that in the group B after the treatment of 15 days （P〈O.05）. After the treatment of 30 days, the ABR threshold in the group C was obviously lower than that in the group B （P〈0.01）, and was obviously lower than that before acupuncture （P〈0.01）. Conclusion Acupuncture at ＂Jing Jiaji＂ has definite effect on improving the hearing of deaf guinea pigs.展开更多
To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and ton...To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and tone-pips at 11 different frequencies from 1 to 60 kHz. The ABR waves were recorded and analyzed. The ABR consisted of five to seven positive waves in the first 10 ms after a click stimulus, and the average hearing threshold of component III was 27.86 ± 3.78 dB SPL. Wave III was the largest and most clear. The ABR threshold was related to the tone-pip sitmulus by a "U" shaped curve. The sensitive frequency was approximately 8 kHz in tree shrews. The latencies systematically decreased with increasing stimulus frequencies. The ABR amplitudes of wave III increased as the sound pressure level increased. All of these results provide an empirical basis for future studies of hearing diseases in tree shrews.展开更多
The auditory steady state response （ASSR） may reflect activity from different regions of the brain, depending on the modulation frequency used. In general, responses induced by low rates （_〈40 Hz） emanate mostly ...The auditory steady state response （ASSR） may reflect activity from different regions of the brain, depending on the modulation frequency used. In general, responses induced by low rates （_〈40 Hz） emanate mostly from central structures of the brain, and responses from high rates （〉80 Hz） emanate mostly from the peripheral auditory nerve or brainstem structures. Besides, it was reported that the gamma band ASSR （30-90 Hz） played an important role in working memory, speech understanding and recognition. This paper investigated the 40 Hz ASSR evoked by modulated speech and reversed speech. The speech was Chinese phrase voice, and the noise-like reversed speech was obtained by temporally reversing the speech. Both auditory stimuli were modulated with a frequency of 40 Hz. Ten healthy subjects and 5 patients with hallucination symptom participated in the experiment. Results showed re- duction in left auditory cortex response when healthy subjects listened to the reversed speech compared with the speech. In contrast, when the patients who experienced auditory hallucinations listened to the reversed speech, the auditory cortex of left hemispheric responded more actively. The ASSR results were consistent with the behavior results of patients. Therefore, the gamma band ASSR is expected to be helpful for rapid and objective diagnosis of hallucination in clinic.展开更多
The auditory brainstern responses(ABR)and middle latency responses(MLR)were recorded in 24 normal mice with a 7S11A processor,and the normalparameters of ABR and MLR obtained.The results showed that the ABR of mice we...The auditory brainstern responses(ABR)and middle latency responses(MLR)were recorded in 24 normal mice with a 7S11A processor,and the normalparameters of ABR and MLR obtained.The results showed that the ABR of mice werecomposed of 6 waves,waves Ⅰ to Ⅵ.The mean threshold was 35.12±8.03 dB ,whichwas significantly different from the 22.63 dB of ABR found in guinea pigs.Thelatency of ABR waves Ⅰ to Ⅵizn the mice was found to be 1.30±8.03 ms ;2.02±0.24ms ;2.90±0.27 ms ;3.80±0.24 ms ;4.87±0.42 ms and 5.83±0.40 ms respectively.Nosex or strain differences were found.The MLR waveform of the mice were similar tothose of human and the latency was found to be P0 3.94±1.76 ms;P8.38±1.57ms;Na 14.98±2.54 ms;Pa 24.56±3.15 ms rcspectively.It is suggested that mice can beused for hearing research.Since the Na and Pa waves of MLR were unstable under anes-thesia,testing conditions for determining MLR in mice need further study.展开更多
The auditory brainstem response (ABR) was measured for 90 cars of norml gui-nea pigs,from which the mean latency,amplitude and recognition of waves were obtain-ded.The waves were classified into six types,with wave Ⅲ...The auditory brainstem response (ABR) was measured for 90 cars of norml gui-nea pigs,from which the mean latency,amplitude and recognition of waves were obtain-ded.The waves were classified into six types,with wave Ⅲ as the main wave which ac-counted for 77.1% of all the waves.The frequency domain of each type was analysed bymeans of digital filtering and auto-regressive (AR)estimation.The main frequency com-position of ABR in the guinea pigs was restricted within 1600 Hz,in which there werethree peaks at AR spectrum,the mean value of the peaks being 107.33 Hz,566.67 Hzand 1076 Hz respectively.The AR spectrograms of all types waves were very similar toeach other.展开更多
Objective To analyze the characteristics of auditory brainstem response (ABR) in presbycusis patients el-der than 90 years. Methods Fourteen presbycusis patients elder than 90 years (presbycusis group, 91.1.4 ± 1...Objective To analyze the characteristics of auditory brainstem response (ABR) in presbycusis patients el-der than 90 years. Methods Fourteen presbycusis patients elder than 90 years (presbycusis group, 91.1.4 ± 1.3 years, 26 ears) and 9 normal-hearing young adults (control group, 22.7 ± 1.2 years, 18 ears) participated in the study. Alternative click-evoked ABRs were recorded in both groups. The peak latency (PL) of peak I,Ⅲ, and V, and the inter-peak latency (IPI) of I-Ⅲ,Ⅲ-V, and I-V were compared between groups. Results In elder presbycusis patients, the occurrence rate of peak I andⅢwere both 76.9%, and that of peak V was 84.6%. In presbycusis group, the peak latencies of I, Ⅲ, V were significantly longer than that of control group (P<0.001). There was no significant difference between groups in the IPI of peak I-IⅢ (P=0.298, peakⅢ-V (P=0.254) and peak I-V (P=0.364). Conclusions Auditory brainstem responses in presbycusis pa-tients elder than 90 years showed worse wave differentiation.展开更多
The analysis of the Auditory Brainstem Response (ABR) is of fundamental importance to the investigation of the auditory system behavior, though its interpretation has a subjective nature because of the manual process ...The analysis of the Auditory Brainstem Response (ABR) is of fundamental importance to the investigation of the auditory system behavior, though its interpretation has a subjective nature because of the manual process employed in its study and the clinical experience required for its analysis. When analyzing the ABR, clinicians are often interested in the identification of ABR signal components referred to as Jewett waves. In particular, the detection and study of the time when these waves occur (i.e., the wave latency) is a practical tool for the diagnosis of disorders affecting the auditory system. In this context, the aim of this research is to compare ABR manual/visual analysis provided by different examiners. Methods: The ABR data were collected from 10 normal-hearing subjects (5 men and 5 women, from 20 to 52 years). A total of 160 data samples were analyzed and a pair- wise comparison between four distinct examiners was executed. We carried out a statistical study aiming to identify significant differences between assessments provided by the examiners. For this, we used Linear Regression in conjunction with Bootstrap, as a method for evaluating the relation between the responses given by the examiners. Results: The analysis suggests agreement among examiners however reveals differences between assessments of the variability of the waves. We quantified the magnitude of the obtained wave latency differences and 18% of the investigated waves presented substantial differences (large and moderate) and of these 3.79% were considered not acceptable for the clinical practice. Conclusions: Our results characterize the variability of the manual analysis of ABR data and the necessity of establishing unified standards and protocols for the analysis of these data. These results may also contribute to the validation and development of automatic systems that are employed in the early diagnosis of hearing loss.展开更多
Objectives:The objective of the study was to explore the impact of auditory stimulation protocol on auditory response in cerebrovascular stroke(CVS)patients.Materials and Methods:A pre-posttest nonequivalent control g...Objectives:The objective of the study was to explore the impact of auditory stimulation protocol on auditory response in cerebrovascular stroke(CVS)patients.Materials and Methods:A pre-posttest nonequivalent control group quasi-experimental study was conducted at Al Mainal Hospital at Al Kars Einy Hospital,Cairo University,among 60 CVS patients,and the sample was randomly assigned through a coin to allocate subjects to study or control group(30 for each group).Auditory stimulation techniques were applied three times per week for the study group for two consecutive weeks.Patients in the control group received only routine hospital care during the study period.The Glasgow Coma Scale(GCS)score for assessing the neurological function and level of arousal and the auditory subscale score of Western Neuro Sensory Stimulation Profile(WNSSP)for assessing auditory response were recorded and compared between the two groups before and after the intervention.Results:There were statistically significant differences between the study group and the control group regarding third reading of GCS score(11.5±0.3 vs.10.6±0.9,t=4.676,P=0.000).The scores of all auditory subscales of WNSSP in the study groups increased after implementing the auditory stimulation protocol(P<0.05).Conclusion:Utilizing the auditory stimulation protocol by nurse proves to be an effective method for enhancing hearing responses in individuals with CVS.展开更多
BACKGROUND: Auditory steady-state evoked response (ASSR) is one of the new objective electrophysiological methods to test hearing in infants. It can provide a reliable and complete audiogram with specific frequency to...BACKGROUND: Auditory steady-state evoked response (ASSR) is one of the new objective electrophysiological methods to test hearing in infants. It can provide a reliable and complete audiogram with specific frequency to help the hearing diagnosis and rehabilitation of hearing and languaging following auditory screening. OBJECTIVE: To compare the response threshold of ASSR with auditory threshold of visual reinforcement audiometry (VRA) in infants failed in the hearing screening for investigating their hearing loss. DESIGN: A comparative observation. SETTINGS: Maternal and child health care hospitals of Guangdong province, Shunde city, Nanhai city and Huadu district. PARTICIPANTS: Totally 321 infants of 0-3 years undergoing ASSR test were selected from the Hearing Center of Guangdong Maternal and Child Health Care Hospital from January 2002 to December 2004. Informed consents were obtained from their guardians. There were 193 cases (60.2%) of 0-6 months, 31 cases (9.7%) of 7-12 months, 17 cases (5.3%) of 13-18 months, 14 cases (4.4%) of 19-24 months, 33 cases of 25-30 months, and 33 cases (10.2%) of 31-36 months. METHODS: ① The 321 infants failed in the hearing screening were tested under sleeping status, the ranges of response threshold distribution in ASSR of different frequencies were analyzed in each age group. ② The infants above 2 years old were also tested with VRA, and their response thresholds were compared between VRA and ASSR. ③ Evaluative standards: The response threshold was < 30 dB for normal hearing, 31-50 dB for mild hearing loss, 51-70 dB for moderate hearing loss, 71-90 dB for severe hearing loss, and > 91 dB for extremely severe hearing loss. MAIN OUTCOME MEASURES: ① ASSR results of the infants failed in the screening; ② Proportion of cases of each response threshold in each age group; ③ Comparison of ASSR response thresholds and VRA auditory thresholds in the infants of 2-3 years old. RESULTS: ①The response threshold was < 30 dB in 47.4% of the 321 infants failed in the initial hearing screening and secondary screening after 42 days. ② Severe to extremely severe hearing loss was detected in only 16 cases (8.3%) of the 193 infants of 0-6 months, in 9 cases (27.3%) of the 33 infants of 25-30 months, and 13 cases (39.4%) of the 33 infants of 31-36 months. Of the 193 infants of 0-6 months old who failed in the initial screening and the second screening after 42 days, the ASSR auditory threshold was < 30 dB in 97 cases (50.26%), 31-50 dB in 63 cases (32.6%), 51-70 dB in 17 cases (8.8%), 71-90 dB in 7 cases (3.6%), and > 91 dB in 9 cases (4.7%). ③ Among the 321 infants failed in the screening, the auditory threshold in the 6 age groups was < 30 dB in 47.4%, 31-50 dB in 27.1%, 51-70 dB in 8.4%, 71-90 dB in 6.2%, and > 91 dB in 10.9%. ④ The difference between ASSR response threshold and VRA auditory thresholds was 6-18 dB in the normal hearing group, mild and moderate hearing loss groups, and there was high correlation between them. The difference of ASSR and VRA thresholds was less than 5 dB between extremely severe and severe hearing loss groups, 5-13 dB between extremely severe and moderate-to-severe hearing loss groups (P < 0.05), and there was no significant differences between severe and moderate-to-severe hearing loss groups (P > 0.05). CONCLUSION: ① The hearing was normal in about half of the infants, although they failed in the primary screening and secondary screening. ② The proportion of the severity of hearing loss was increased along with aging. ③ Mild and moderate hearing losses are dominant in infants. ④ ASSR is reliable to evaluate the hearing of infants.展开更多
This exploratory study examined the short-term reliability of cortical auditory evoked responses recorded from patients undergoing whole-head scalp elec-troencephalography (EEG) monitoring to assess their candidacy fo...This exploratory study examined the short-term reliability of cortical auditory evoked responses recorded from patients undergoing whole-head scalp elec-troencephalography (EEG) monitoring to assess their candidacy for surgical treatment of intractable focal seizures. Participants were 26 patients with either left-sided (N = 13) or right-sided focal epilepsy admitted to the hospital for continuous scalp EEG monitoring for possible epilepsy surgery planning. Cortical auditory evoked responses were recorded over multiple days from scalp EEG electrodes using tones presented binaurally in a passive oddball paradigm. Test-retest intervals were 1 - 6 days (mean 2 days). Test-retest reproducibility of the auditory N1 response was assessed by paired t-test (latency) and cross-correlation analysis (amplitude and latency). Within-patient comparisons of test-retest auditory N1 peak latencies revealed no significant differences. The cross-correlation coefficient indicated high test-retest reproducibility of the N1 waveform (rcc = 0.88). Seizure lateralization was not associated with asymmetries in N1 latencies or amplitudes. An N1 amplitude asymmetry (right > left) in patients with focal seizures originating from the left hemisphere was initially observed, but disappeared when patients with prior resections were excluded, suggesting that reduced left hemisphere tissue volume may account for the smaller N1 amplitudes. Test-retest reliability of cortical auditory evoked responses was unexpectedly high in patients with focal epilepsy regardless of seizure lateralization or localization. These findings challenge the view that neural responses are intrinsically unstable (unreliable) in patients with seizures.展开更多
Objectives To investigate changes in evoked potentials and structure of the guinea pig cochleae during whole cochlear perfusion with glutamate.Methods CM,CAP,DPOAE,and ABR were recorded as indicators of cochlear funct...Objectives To investigate changes in evoked potentials and structure of the guinea pig cochleae during whole cochlear perfusion with glutamate.Methods CM,CAP,DPOAE,and ABR were recorded as indicators of cochlear functions during whole cochlear perfusion.The morphology of the cochlea was studied via transmission electron microscopy.Results There were no significant changes in DPOAE amplitude before and after glutamate perfusion.CM I/O function remained nonlinear during perfusion.ABR latencies were delayed following glutamate perfusion.The average CAP threshold was elevated 35 dB SPL following glutamate perfusion..The OHCs appeared normal,but the IHCs and afferent dendrites showed cytoplasmic blebs after glutamate perfusion.Conclusions While being a primary amino acid neurotransmitter at the synapses between hair cells and spiral ganglion neurons,excessive glutamate is neurotoxic and can destroy IHCs and spiral ganglion neurons.The technique used in this study can also be used to build an animal model of auditory neuropathy.展开更多
Tinnitus is a concerning condition that affects most adults worldwide,with a prevalence of 6.7%.Theories of tinnitus have explained that an increase in spontaneous neural activity at the level of the thalamus could in...Tinnitus is a concerning condition that affects most adults worldwide,with a prevalence of 6.7%.Theories of tinnitus have explained that an increase in spontaneous neural activity at the level of the thalamus could induce tinnitus.There are no standardized objective tests for tinnitus assessment because of its multifaceted nature.Hence,the current study aimed to explore the effect of Tinnitus on Latency and Amplitude of the Auditory Middle Latency Response in Audiological Attendees.The study recruited 50 individuals(25 normals and 25 individuals with tinnitus)who underwent audiological evaluations like Pure tone audiometry,immittance,pitch and loudness matching,THI and middle latency response.The IHS program was used to record MLR,which was obtained using tone burst stimuli of 500 Hz,1 KHz,2 KHz,and 4 KHz at a rate of 7.1/s with a constant duration of 5 ms,for a total of 1500 sweeps.As a covariate,pure tone thresholds were one of the variabilities that were addressed by ANCOVA.The amplitude of the Pa component varied significantly between the tinnitus and control groups,according to the MLR data and no other components of MLR reached that significance.Furthermore,there was no discernible variation in the latency or amplitude of MLR among any of the other components.The latency of the waveforms increased as the stimulus frequency increased.Karl Pearson correlation coefficient showed no significant correlation between THI scores and any of the outcome measures except for Pa amplitude.As the Pa component of MLR showed maximum changes between controls and individuals with tinnitus,the Pa component could be considered a potential tool for identifying neurophysiological changes related to tinnitus.展开更多
Information on hearing thresholds is not always reliable as differences in these thresholds have been described even for the same species. This may partially be due to different methods used by different labs. A frequ...Information on hearing thresholds is not always reliable as differences in these thresholds have been described even for the same species. This may partially be due to different methods used by different labs. A frequently used approach to obtain an estimate of hearing threshold is the electrophysiological recording of auditory brainstem responses (ABR). They are usually recorded under deep anesthesia and represent the auditory evoked far-field potentials at various levels in the central auditory pathway. Alternatively, several behavioral approaches are employed. These commonly use operant or classical conditioning to determine hearing thresholds. A potential disadvantage of these methods is that any sound conditioning may in principle alter auditory perception and therefore auditory thresholds. To exclude this type of methodological bias a prepulse inhibition (PPI) paradigm can be used where an audiogram can be determined without any kind of pre-training. Here we compare the threshold estimates obtained by two different ABR and PPI measurements where stimuli are presented in different contexts, either randomly or non-randomly, to test for a possible effect of auditory sensitization. In addition we test the effect of a frequency specific acoustic trauma on the audiograms obtained with both methods. In general we find behaviorally determined audiograms to be significantly lower in absolute thresh- old compared to ABR measurements. Furthermore non-randomized presentation context of the stimuli generally results in audiograms with 10 to 15 dB lower thresholds than pseudo-randomized presentation. Finally, the amount of threshold loss induced by acoustic trauma is similar for all methods tested.展开更多
Tinnitus has often been studied using salicylate in animal models as they are capable of inducing tempo-rary hearing loss and tinnitus. Studies have recently observed enhancement of auditory evoked responses of the au...Tinnitus has often been studied using salicylate in animal models as they are capable of inducing tempo-rary hearing loss and tinnitus. Studies have recently observed enhancement of auditory evoked responses of the auditory cortex (AC) post salicylate treatment which is also shown to be related to tinnitus like behavior in rats. The aim of this study was to observe if enhancements of the AC post salicylate treatment are also present at structures in the brainstem. Four male Sprague Dawley rats with AC implanted electrodes were tested for both AC and auditory brainstem response (ABR) recordings pre and post 250 mg/kg intraperitone-al injections of salicylate. The responses were recorded as the peak to trough amplitudes of P1-N1 (AC), ABR wave V, and ABR waveⅡ. AC responses resulted in statistically significant enhancement of ampli-tude at 2 hours post salicylate with 90 dB stimuli tone bursts of 4, 8, 12, and 20 kHz. Wave V of ABR re-sponses at 90 dB resulted in a statistically significant reduction of amplitude 2 hours post salicylate and a mean decrease of amplitude of 31%for 16 kHz. WaveⅡamplitudes at 2 hours post treatment were signifi-cantly reduced for 4, 12, and 20 kHz stimuli at 90 dB SPL. Our results suggest that the enhancement chang-es of the AC related to salicylate induced tinnitus are generated superior to the level of the inferior colliculus and may originate in the AC.展开更多
Vocalizations play a critical role in mate recognition and mate choice in a number of taxa, especially, but not limited to, orthopterans, frogs, and birds. But receivers can only recognize and prefer sounds that they ...Vocalizations play a critical role in mate recognition and mate choice in a number of taxa, especially, but not limited to, orthopterans, frogs, and birds. But receivers can only recognize and prefer sounds that they can hear. Thus a fundamental question linking neurobiology and sexual selection asks-what is the threshold for detecting acoustic sexual displays? In this study, we use 3 methods to assess such thresholds in tdngara frogs: behavioral responses, auditory brainstem responsesz and multi unit electrophysiological recordi ngs from the midbrain.We show that thresholds are lowest for multiunit recordings (ca. 45 dB SPL), and then for behavioral responses (ca. 61 dB SPL), with auditory brainstem responses exhibiting the highest thresholds (ca. 71 dB SPL). We discuss why these estimates differ and why, as with other studies, it is unlikely that they should be the same. Although all of these studies estimate thresholds they are not measuring the same thresholds;behavioral thresholds are based on signal salienee whereas the 2 neural assays estimate physiological thresholds. All 3 estimates, however, make it clear that to have an appreciation for detection and salienee of acoustic signals we must listen to those signals through the ears of the receivers.展开更多
In anurans, calling behaviour is strongly seasonal and circadian. Previous studies have revealed that a uditory sensitivity in frogs exhibits seasonal plasticity, and electroencephalographic signals exhibit highly cor...In anurans, calling behaviour is strongly seasonal and circadian. Previous studies have revealed that a uditory sensitivity in frogs exhibits seasonal plasticity, and electroencephalographic signals exhibit highly correlated circadian patterns;of which, the circadian rhythm remains unknown. In this study,the circadian rhythm and intersexual differences of auditory sensitivity were tested in the Emei music frog(Nidirana daunchina). This was achieved by comparing thresholds and latencies of auditory brainstem responses(ABRs) evoked by tones and clicks stimuli between male and female frogs during the day and at night,respectively. Our results revealed that both auditory thresholds and latencies had no differences between day and night except the la tencies in 3.5–4.0 kHz frequencies. However, the thresholds of tone pip evoked ABRs differed significantly between male and female frogs from 2.5 to 5.0 kHz. This demonstrated that the auditory sensitivity of Emei music frogs exhibits sexual dimorphism at high frequencies, with female frogs exhibiting greater auditory sensitivity than that of male frogs. Simultaneously, the power spectra of male advertisement calls are matched well with the frequency range of auditory sensitivity in male and female frogs,which supports the matched filter hypothesis. Our study enhances the understanding of circadian plasticity and sexual dimorphism of auditory sensitivity in frogs.展开更多
Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 1...Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 14 subjects were as- signed randomly into groups consisting of 2 members. Both the members from each group performed both the visual and auditory tests. The tests were taken from the DirectRT software program from a laptop. The DirectRT software consists of Testlabvisual and Testlabsounds to test the reaction times to visual and auditory stimuli. The 2 members from each group completed both the visual and auditory reaction times, the data was taken and the mean reaction time was calculated excluding the first and last values. Results: The results show that the mean visual reaction time is around 331 milliseconds as compared to the mean auditory reaction time of around 284 milliseconds. Conclusion: This shows that the auditory reaction time is faster than the visual reaction time. And also males have faster reaction times when compared to females for both auditory as well as visual stimuli.展开更多
Objective To study local inflammatory response after implantation of hydroxyapatite synthetic ossicular prosthesis.Methods Hydroxyapatite granules were implanted in the bulla in 32 rats.Sham surgical procedures were p...Objective To study local inflammatory response after implantation of hydroxyapatite synthetic ossicular prosthesis.Methods Hydroxyapatite granules were implanted in the bulla in 32 rats.Sham surgical procedures were performed in 10 rats as the control.Animals were sacrificed at 1 to 300 days after surgery.Bulla sections,stained with HE and Mallory’s azan,were examined for numbers and percentages of various inflammatory cell types.Results Slightly more inflammatory reaction was seen in animals with the implant than in the controls,mostly during the early stage following the implantation procedure.Few inflammatory cells were observed at later times.There were satisfactory fibrosis in both implanted and control ears.Conclusion The results indicate that hydroxyapatite synthetic prosthesis is a biocompatible implantation material in the middle ear.Nonetheless,the presence of inflammatory reaction immediately following implantation implies that control of infection is important in the early times after the implantation procedure.展开更多
Adult guinea pigs with normal Preyer’s reflexes were used in this experiment and were di-vided into 3 groups according to the intensity of noise and exposure time.Auditory brainstemevoked response was recorded before...Adult guinea pigs with normal Preyer’s reflexes were used in this experiment and were di-vided into 3 groups according to the intensity of noise and exposure time.Auditory brainstemevoked response was recorded before and after exposure to noise.Clicks were presented monaurallyat a rate of high (50Hz) as well as low (10Hz).The superior olive and inferior colliculus were ob-served under an electron microscope after the guinea pigs were exposured to 110dB noise for30min.The average shift of wave Ⅳ amplitude-intensity function curve was more than that ofwave Ⅰ after exposure to intensive noise.The difference value of wave \ latency from low(10Hz) to high (50Hz) stimulus click rate decreased and was negatively correlated with the exposuretime.Ⅰ-Ⅴ,Ⅲ-Ⅴ and Ⅳ-Ⅴ interpeak latencies were shorter after exposure to noise.Themitochondria and neurilemma swelling were found in the superior olive and inferior colliculus afterexposure,Some mechanisms of the changes of auditory center were discussed in this paper.展开更多
基金Supported by Yanbian University on Scientific Development and Application:No.36,yanda kehe zi[2013]
文摘Objective To explore the effect of acupuncture at ＂Jing Jiaji＂ （颈夹背） on sudden hearing loss by observing the changes of the threshold of auditory brainstem response （ABR） of deaf guinea pigs. Methods Sixty healthy guinea pigs were selected, with computer randomization, 20 were randomly divided into a normal control group （group A）, while the rest were randomly and equally divided into a model group （group B） and an acupuncture group （group C） when turned deaf after gentamycin sulfate and furosemide were administered. No treatment was administered for either the group A or the group B, while acupuncture at ＂Jing Jiaji＂ was given for the group C for 30 days. The ABR thresholds of each group were observed and recorded separately after the treatment for 15 days and 30 days. Results The ABR threshold in the group C was lower than that in the group B after the treatment of 15 days （P〈O.05）. After the treatment of 30 days, the ABR threshold in the group C was obviously lower than that in the group B （P〈0.01）, and was obviously lower than that before acupuncture （P〈0.01）. Conclusion Acupuncture at ＂Jing Jiaji＂ has definite effect on improving the hearing of deaf guinea pigs.
基金supported by Natural Science Foundation of China[grant numbers 81760188]Scientific Research Fund of Guangxi Provincial Education Department [grant numbers 2017KY0103 (02601217023C)]
文摘To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and tone-pips at 11 different frequencies from 1 to 60 kHz. The ABR waves were recorded and analyzed. The ABR consisted of five to seven positive waves in the first 10 ms after a click stimulus, and the average hearing threshold of component III was 27.86 ± 3.78 dB SPL. Wave III was the largest and most clear. The ABR threshold was related to the tone-pip sitmulus by a "U" shaped curve. The sensitive frequency was approximately 8 kHz in tree shrews. The latencies systematically decreased with increasing stimulus frequencies. The ABR amplitudes of wave III increased as the sound pressure level increased. All of these results provide an empirical basis for future studies of hearing diseases in tree shrews.
基金supported by the National Natural Science Foundation of China(No.90820304,61105123,and 31100714)National Basic Research Program of China(No.2011CB933204)
文摘The auditory steady state response （ASSR） may reflect activity from different regions of the brain, depending on the modulation frequency used. In general, responses induced by low rates （_〈40 Hz） emanate mostly from central structures of the brain, and responses from high rates （〉80 Hz） emanate mostly from the peripheral auditory nerve or brainstem structures. Besides, it was reported that the gamma band ASSR （30-90 Hz） played an important role in working memory, speech understanding and recognition. This paper investigated the 40 Hz ASSR evoked by modulated speech and reversed speech. The speech was Chinese phrase voice, and the noise-like reversed speech was obtained by temporally reversing the speech. Both auditory stimuli were modulated with a frequency of 40 Hz. Ten healthy subjects and 5 patients with hallucination symptom participated in the experiment. Results showed re- duction in left auditory cortex response when healthy subjects listened to the reversed speech compared with the speech. In contrast, when the patients who experienced auditory hallucinations listened to the reversed speech, the auditory cortex of left hemispheric responded more actively. The ASSR results were consistent with the behavior results of patients. Therefore, the gamma band ASSR is expected to be helpful for rapid and objective diagnosis of hallucination in clinic.
文摘The auditory brainstern responses(ABR)and middle latency responses(MLR)were recorded in 24 normal mice with a 7S11A processor,and the normalparameters of ABR and MLR obtained.The results showed that the ABR of mice werecomposed of 6 waves,waves Ⅰ to Ⅵ.The mean threshold was 35.12±8.03 dB ,whichwas significantly different from the 22.63 dB of ABR found in guinea pigs.Thelatency of ABR waves Ⅰ to Ⅵizn the mice was found to be 1.30±8.03 ms ;2.02±0.24ms ;2.90±0.27 ms ;3.80±0.24 ms ;4.87±0.42 ms and 5.83±0.40 ms respectively.Nosex or strain differences were found.The MLR waveform of the mice were similar tothose of human and the latency was found to be P0 3.94±1.76 ms;P8.38±1.57ms;Na 14.98±2.54 ms;Pa 24.56±3.15 ms rcspectively.It is suggested that mice can beused for hearing research.Since the Na and Pa waves of MLR were unstable under anes-thesia,testing conditions for determining MLR in mice need further study.
文摘The auditory brainstem response (ABR) was measured for 90 cars of norml gui-nea pigs,from which the mean latency,amplitude and recognition of waves were obtain-ded.The waves were classified into six types,with wave Ⅲ as the main wave which ac-counted for 77.1% of all the waves.The frequency domain of each type was analysed bymeans of digital filtering and auto-regressive (AR)estimation.The main frequency com-position of ABR in the guinea pigs was restricted within 1600 Hz,in which there werethree peaks at AR spectrum,the mean value of the peaks being 107.33 Hz,566.67 Hzand 1076 Hz respectively.The AR spectrograms of all types waves were very similar toeach other.
基金supported by grants from the Science and Technology Innovation Nursery Foundation of PLA General Hospital(12KMM29)the military medical metrology research project(2012-JL1-028)+1 种基金Clinical Research Supporting Foundation of PLA General Hospital(2012FC-TSYS-3056)the Military Medical and Sanitation Research Project(11BJZ33)
文摘Objective To analyze the characteristics of auditory brainstem response (ABR) in presbycusis patients el-der than 90 years. Methods Fourteen presbycusis patients elder than 90 years (presbycusis group, 91.1.4 ± 1.3 years, 26 ears) and 9 normal-hearing young adults (control group, 22.7 ± 1.2 years, 18 ears) participated in the study. Alternative click-evoked ABRs were recorded in both groups. The peak latency (PL) of peak I,Ⅲ, and V, and the inter-peak latency (IPI) of I-Ⅲ,Ⅲ-V, and I-V were compared between groups. Results In elder presbycusis patients, the occurrence rate of peak I andⅢwere both 76.9%, and that of peak V was 84.6%. In presbycusis group, the peak latencies of I, Ⅲ, V were significantly longer than that of control group (P<0.001). There was no significant difference between groups in the IPI of peak I-IⅢ (P=0.298, peakⅢ-V (P=0.254) and peak I-V (P=0.364). Conclusions Auditory brainstem responses in presbycusis pa-tients elder than 90 years showed worse wave differentiation.
文摘The analysis of the Auditory Brainstem Response (ABR) is of fundamental importance to the investigation of the auditory system behavior, though its interpretation has a subjective nature because of the manual process employed in its study and the clinical experience required for its analysis. When analyzing the ABR, clinicians are often interested in the identification of ABR signal components referred to as Jewett waves. In particular, the detection and study of the time when these waves occur (i.e., the wave latency) is a practical tool for the diagnosis of disorders affecting the auditory system. In this context, the aim of this research is to compare ABR manual/visual analysis provided by different examiners. Methods: The ABR data were collected from 10 normal-hearing subjects (5 men and 5 women, from 20 to 52 years). A total of 160 data samples were analyzed and a pair- wise comparison between four distinct examiners was executed. We carried out a statistical study aiming to identify significant differences between assessments provided by the examiners. For this, we used Linear Regression in conjunction with Bootstrap, as a method for evaluating the relation between the responses given by the examiners. Results: The analysis suggests agreement among examiners however reveals differences between assessments of the variability of the waves. We quantified the magnitude of the obtained wave latency differences and 18% of the investigated waves presented substantial differences (large and moderate) and of these 3.79% were considered not acceptable for the clinical practice. Conclusions: Our results characterize the variability of the manual analysis of ABR data and the necessity of establishing unified standards and protocols for the analysis of these data. These results may also contribute to the validation and development of automatic systems that are employed in the early diagnosis of hearing loss.
文摘Objectives:The objective of the study was to explore the impact of auditory stimulation protocol on auditory response in cerebrovascular stroke(CVS)patients.Materials and Methods:A pre-posttest nonequivalent control group quasi-experimental study was conducted at Al Mainal Hospital at Al Kars Einy Hospital,Cairo University,among 60 CVS patients,and the sample was randomly assigned through a coin to allocate subjects to study or control group(30 for each group).Auditory stimulation techniques were applied three times per week for the study group for two consecutive weeks.Patients in the control group received only routine hospital care during the study period.The Glasgow Coma Scale(GCS)score for assessing the neurological function and level of arousal and the auditory subscale score of Western Neuro Sensory Stimulation Profile(WNSSP)for assessing auditory response were recorded and compared between the two groups before and after the intervention.Results:There were statistically significant differences between the study group and the control group regarding third reading of GCS score(11.5±0.3 vs.10.6±0.9,t=4.676,P=0.000).The scores of all auditory subscales of WNSSP in the study groups increased after implementing the auditory stimulation protocol(P<0.05).Conclusion:Utilizing the auditory stimulation protocol by nurse proves to be an effective method for enhancing hearing responses in individuals with CVS.
基金a grant from Medical Scientific Research Foundation of G uangdong Bureau of Hygiene,No.W STJJ2001111044082219581224001
文摘BACKGROUND: Auditory steady-state evoked response (ASSR) is one of the new objective electrophysiological methods to test hearing in infants. It can provide a reliable and complete audiogram with specific frequency to help the hearing diagnosis and rehabilitation of hearing and languaging following auditory screening. OBJECTIVE: To compare the response threshold of ASSR with auditory threshold of visual reinforcement audiometry (VRA) in infants failed in the hearing screening for investigating their hearing loss. DESIGN: A comparative observation. SETTINGS: Maternal and child health care hospitals of Guangdong province, Shunde city, Nanhai city and Huadu district. PARTICIPANTS: Totally 321 infants of 0-3 years undergoing ASSR test were selected from the Hearing Center of Guangdong Maternal and Child Health Care Hospital from January 2002 to December 2004. Informed consents were obtained from their guardians. There were 193 cases (60.2%) of 0-6 months, 31 cases (9.7%) of 7-12 months, 17 cases (5.3%) of 13-18 months, 14 cases (4.4%) of 19-24 months, 33 cases of 25-30 months, and 33 cases (10.2%) of 31-36 months. METHODS: ① The 321 infants failed in the hearing screening were tested under sleeping status, the ranges of response threshold distribution in ASSR of different frequencies were analyzed in each age group. ② The infants above 2 years old were also tested with VRA, and their response thresholds were compared between VRA and ASSR. ③ Evaluative standards: The response threshold was < 30 dB for normal hearing, 31-50 dB for mild hearing loss, 51-70 dB for moderate hearing loss, 71-90 dB for severe hearing loss, and > 91 dB for extremely severe hearing loss. MAIN OUTCOME MEASURES: ① ASSR results of the infants failed in the screening; ② Proportion of cases of each response threshold in each age group; ③ Comparison of ASSR response thresholds and VRA auditory thresholds in the infants of 2-3 years old. RESULTS: ①The response threshold was < 30 dB in 47.4% of the 321 infants failed in the initial hearing screening and secondary screening after 42 days. ② Severe to extremely severe hearing loss was detected in only 16 cases (8.3%) of the 193 infants of 0-6 months, in 9 cases (27.3%) of the 33 infants of 25-30 months, and 13 cases (39.4%) of the 33 infants of 31-36 months. Of the 193 infants of 0-6 months old who failed in the initial screening and the second screening after 42 days, the ASSR auditory threshold was < 30 dB in 97 cases (50.26%), 31-50 dB in 63 cases (32.6%), 51-70 dB in 17 cases (8.8%), 71-90 dB in 7 cases (3.6%), and > 91 dB in 9 cases (4.7%). ③ Among the 321 infants failed in the screening, the auditory threshold in the 6 age groups was < 30 dB in 47.4%, 31-50 dB in 27.1%, 51-70 dB in 8.4%, 71-90 dB in 6.2%, and > 91 dB in 10.9%. ④ The difference between ASSR response threshold and VRA auditory thresholds was 6-18 dB in the normal hearing group, mild and moderate hearing loss groups, and there was high correlation between them. The difference of ASSR and VRA thresholds was less than 5 dB between extremely severe and severe hearing loss groups, 5-13 dB between extremely severe and moderate-to-severe hearing loss groups (P < 0.05), and there was no significant differences between severe and moderate-to-severe hearing loss groups (P > 0.05). CONCLUSION: ① The hearing was normal in about half of the infants, although they failed in the primary screening and secondary screening. ② The proportion of the severity of hearing loss was increased along with aging. ③ Mild and moderate hearing losses are dominant in infants. ④ ASSR is reliable to evaluate the hearing of infants.
文摘This exploratory study examined the short-term reliability of cortical auditory evoked responses recorded from patients undergoing whole-head scalp elec-troencephalography (EEG) monitoring to assess their candidacy for surgical treatment of intractable focal seizures. Participants were 26 patients with either left-sided (N = 13) or right-sided focal epilepsy admitted to the hospital for continuous scalp EEG monitoring for possible epilepsy surgery planning. Cortical auditory evoked responses were recorded over multiple days from scalp EEG electrodes using tones presented binaurally in a passive oddball paradigm. Test-retest intervals were 1 - 6 days (mean 2 days). Test-retest reproducibility of the auditory N1 response was assessed by paired t-test (latency) and cross-correlation analysis (amplitude and latency). Within-patient comparisons of test-retest auditory N1 peak latencies revealed no significant differences. The cross-correlation coefficient indicated high test-retest reproducibility of the N1 waveform (rcc = 0.88). Seizure lateralization was not associated with asymmetries in N1 latencies or amplitudes. An N1 amplitude asymmetry (right > left) in patients with focal seizures originating from the left hemisphere was initially observed, but disappeared when patients with prior resections were excluded, suggesting that reduced left hemisphere tissue volume may account for the smaller N1 amplitudes. Test-retest reliability of cortical auditory evoked responses was unexpectedly high in patients with focal epilepsy regardless of seizure lateralization or localization. These findings challenge the view that neural responses are intrinsically unstable (unreliable) in patients with seizures.
文摘Objectives To investigate changes in evoked potentials and structure of the guinea pig cochleae during whole cochlear perfusion with glutamate.Methods CM,CAP,DPOAE,and ABR were recorded as indicators of cochlear functions during whole cochlear perfusion.The morphology of the cochlea was studied via transmission electron microscopy.Results There were no significant changes in DPOAE amplitude before and after glutamate perfusion.CM I/O function remained nonlinear during perfusion.ABR latencies were delayed following glutamate perfusion.The average CAP threshold was elevated 35 dB SPL following glutamate perfusion..The OHCs appeared normal,but the IHCs and afferent dendrites showed cytoplasmic blebs after glutamate perfusion.Conclusions While being a primary amino acid neurotransmitter at the synapses between hair cells and spiral ganglion neurons,excessive glutamate is neurotoxic and can destroy IHCs and spiral ganglion neurons.The technique used in this study can also be used to build an animal model of auditory neuropathy.
文摘Tinnitus is a concerning condition that affects most adults worldwide,with a prevalence of 6.7%.Theories of tinnitus have explained that an increase in spontaneous neural activity at the level of the thalamus could induce tinnitus.There are no standardized objective tests for tinnitus assessment because of its multifaceted nature.Hence,the current study aimed to explore the effect of Tinnitus on Latency and Amplitude of the Auditory Middle Latency Response in Audiological Attendees.The study recruited 50 individuals(25 normals and 25 individuals with tinnitus)who underwent audiological evaluations like Pure tone audiometry,immittance,pitch and loudness matching,THI and middle latency response.The IHS program was used to record MLR,which was obtained using tone burst stimuli of 500 Hz,1 KHz,2 KHz,and 4 KHz at a rate of 7.1/s with a constant duration of 5 ms,for a total of 1500 sweeps.As a covariate,pure tone thresholds were one of the variabilities that were addressed by ANCOVA.The amplitude of the Pa component varied significantly between the tinnitus and control groups,according to the MLR data and no other components of MLR reached that significance.Furthermore,there was no discernible variation in the latency or amplitude of MLR among any of the other components.The latency of the waveforms increased as the stimulus frequency increased.Karl Pearson correlation coefficient showed no significant correlation between THI scores and any of the outcome measures except for Pa amplitude.As the Pa component of MLR showed maximum changes between controls and individuals with tinnitus,the Pa component could be considered a potential tool for identifying neurophysiological changes related to tinnitus.
文摘Information on hearing thresholds is not always reliable as differences in these thresholds have been described even for the same species. This may partially be due to different methods used by different labs. A frequently used approach to obtain an estimate of hearing threshold is the electrophysiological recording of auditory brainstem responses (ABR). They are usually recorded under deep anesthesia and represent the auditory evoked far-field potentials at various levels in the central auditory pathway. Alternatively, several behavioral approaches are employed. These commonly use operant or classical conditioning to determine hearing thresholds. A potential disadvantage of these methods is that any sound conditioning may in principle alter auditory perception and therefore auditory thresholds. To exclude this type of methodological bias a prepulse inhibition (PPI) paradigm can be used where an audiogram can be determined without any kind of pre-training. Here we compare the threshold estimates obtained by two different ABR and PPI measurements where stimuli are presented in different contexts, either randomly or non-randomly, to test for a possible effect of auditory sensitization. In addition we test the effect of a frequency specific acoustic trauma on the audiograms obtained with both methods. In general we find behaviorally determined audiograms to be significantly lower in absolute thresh- old compared to ABR measurements. Furthermore non-randomized presentation context of the stimuli generally results in audiograms with 10 to 15 dB lower thresholds than pseudo-randomized presentation. Finally, the amount of threshold loss induced by acoustic trauma is similar for all methods tested.
文摘Tinnitus has often been studied using salicylate in animal models as they are capable of inducing tempo-rary hearing loss and tinnitus. Studies have recently observed enhancement of auditory evoked responses of the auditory cortex (AC) post salicylate treatment which is also shown to be related to tinnitus like behavior in rats. The aim of this study was to observe if enhancements of the AC post salicylate treatment are also present at structures in the brainstem. Four male Sprague Dawley rats with AC implanted electrodes were tested for both AC and auditory brainstem response (ABR) recordings pre and post 250 mg/kg intraperitone-al injections of salicylate. The responses were recorded as the peak to trough amplitudes of P1-N1 (AC), ABR wave V, and ABR waveⅡ. AC responses resulted in statistically significant enhancement of ampli-tude at 2 hours post salicylate with 90 dB stimuli tone bursts of 4, 8, 12, and 20 kHz. Wave V of ABR re-sponses at 90 dB resulted in a statistically significant reduction of amplitude 2 hours post salicylate and a mean decrease of amplitude of 31%for 16 kHz. WaveⅡamplitudes at 2 hours post treatment were signifi-cantly reduced for 4, 12, and 20 kHz stimuli at 90 dB SPL. Our results suggest that the enhancement chang-es of the AC related to salicylate induced tinnitus are generated superior to the level of the inferior colliculus and may originate in the AC.
文摘Vocalizations play a critical role in mate recognition and mate choice in a number of taxa, especially, but not limited to, orthopterans, frogs, and birds. But receivers can only recognize and prefer sounds that they can hear. Thus a fundamental question linking neurobiology and sexual selection asks-what is the threshold for detecting acoustic sexual displays? In this study, we use 3 methods to assess such thresholds in tdngara frogs: behavioral responses, auditory brainstem responsesz and multi unit electrophysiological recordi ngs from the midbrain.We show that thresholds are lowest for multiunit recordings (ca. 45 dB SPL), and then for behavioral responses (ca. 61 dB SPL), with auditory brainstem responses exhibiting the highest thresholds (ca. 71 dB SPL). We discuss why these estimates differ and why, as with other studies, it is unlikely that they should be the same. Although all of these studies estimate thresholds they are not measuring the same thresholds;behavioral thresholds are based on signal salienee whereas the 2 neural assays estimate physiological thresholds. All 3 estimates, however, make it clear that to have an appreciation for detection and salienee of acoustic signals we must listen to those signals through the ears of the receivers.
基金supported by National Natural Science Foundation of China (31772464)Youth Innovation Promotion Association CAS (2012274)。
文摘In anurans, calling behaviour is strongly seasonal and circadian. Previous studies have revealed that a uditory sensitivity in frogs exhibits seasonal plasticity, and electroencephalographic signals exhibit highly correlated circadian patterns;of which, the circadian rhythm remains unknown. In this study,the circadian rhythm and intersexual differences of auditory sensitivity were tested in the Emei music frog(Nidirana daunchina). This was achieved by comparing thresholds and latencies of auditory brainstem responses(ABRs) evoked by tones and clicks stimuli between male and female frogs during the day and at night,respectively. Our results revealed that both auditory thresholds and latencies had no differences between day and night except the la tencies in 3.5–4.0 kHz frequencies. However, the thresholds of tone pip evoked ABRs differed significantly between male and female frogs from 2.5 to 5.0 kHz. This demonstrated that the auditory sensitivity of Emei music frogs exhibits sexual dimorphism at high frequencies, with female frogs exhibiting greater auditory sensitivity than that of male frogs. Simultaneously, the power spectra of male advertisement calls are matched well with the frequency range of auditory sensitivity in male and female frogs,which supports the matched filter hypothesis. Our study enhances the understanding of circadian plasticity and sexual dimorphism of auditory sensitivity in frogs.
文摘Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 14 subjects were as- signed randomly into groups consisting of 2 members. Both the members from each group performed both the visual and auditory tests. The tests were taken from the DirectRT software program from a laptop. The DirectRT software consists of Testlabvisual and Testlabsounds to test the reaction times to visual and auditory stimuli. The 2 members from each group completed both the visual and auditory reaction times, the data was taken and the mean reaction time was calculated excluding the first and last values. Results: The results show that the mean visual reaction time is around 331 milliseconds as compared to the mean auditory reaction time of around 284 milliseconds. Conclusion: This shows that the auditory reaction time is faster than the visual reaction time. And also males have faster reaction times when compared to females for both auditory as well as visual stimuli.
基金a grant from theNational Natural Science Foundation of China(no:60578057).
文摘Objective To study local inflammatory response after implantation of hydroxyapatite synthetic ossicular prosthesis.Methods Hydroxyapatite granules were implanted in the bulla in 32 rats.Sham surgical procedures were performed in 10 rats as the control.Animals were sacrificed at 1 to 300 days after surgery.Bulla sections,stained with HE and Mallory’s azan,were examined for numbers and percentages of various inflammatory cell types.Results Slightly more inflammatory reaction was seen in animals with the implant than in the controls,mostly during the early stage following the implantation procedure.Few inflammatory cells were observed at later times.There were satisfactory fibrosis in both implanted and control ears.Conclusion The results indicate that hydroxyapatite synthetic prosthesis is a biocompatible implantation material in the middle ear.Nonetheless,the presence of inflammatory reaction immediately following implantation implies that control of infection is important in the early times after the implantation procedure.
文摘Adult guinea pigs with normal Preyer’s reflexes were used in this experiment and were di-vided into 3 groups according to the intensity of noise and exposure time.Auditory brainstemevoked response was recorded before and after exposure to noise.Clicks were presented monaurallyat a rate of high (50Hz) as well as low (10Hz).The superior olive and inferior colliculus were ob-served under an electron microscope after the guinea pigs were exposured to 110dB noise for30min.The average shift of wave Ⅳ amplitude-intensity function curve was more than that ofwave Ⅰ after exposure to intensive noise.The difference value of wave \ latency from low(10Hz) to high (50Hz) stimulus click rate decreased and was negatively correlated with the exposuretime.Ⅰ-Ⅴ,Ⅲ-Ⅴ and Ⅳ-Ⅴ interpeak latencies were shorter after exposure to noise.Themitochondria and neurilemma swelling were found in the superior olive and inferior colliculus afterexposure,Some mechanisms of the changes of auditory center were discussed in this paper.
