Changes of auditory evoked magnetic fields in patients after acute cerebral infarction using magnetoencephalography

Auditory evoked magnetic fields were recorded from 15 patients with acute cerebral infarction and 11 healthy volunteers using magnetoencephalography.The auditory stimuli of 2 kHz pure tone were binaurally presented with an interstimulus interval of 1 second.The intensity of stimuli was 90 dB and the stimulus duration was 8 ms.The results showed that the M100 was the prominent response, peaking approximately 100 ms after stimulus onset in all subjects.It originated from the area close to Heschl’s gyrus.In the patient group,the peak latency of M100 responses was significantly prolonged,and the mean strength of equivalent current dipole was significantly smaller in the affected hemisphere.The three-dimensional inter-hemispheric difference of the M100 positions was increased in the patient group.Our experimental findings suggested that impairment of cerebral function in patients with acute ischemic stroke can be detected using magnetoencephalography with the higher spatial resolution and temporal resolution.Magnetoencephalography could provide objective and sensitive indices to estimate auditory cortex function in patients with acute cerebral infarction.

Characteristics of brainstem auditory evoked potentials of students studying folk dance

BACKGROUND： Previous experiments have demonstrated that brainstem auditory evoked potential is affected by exercise, exercise duration, and frequency. OBJECTIVE： Comparing the brainstem auditory evoked potential of students studying folk dance to students studying other subjects. DESIGN： Observational contrast study. SETTING： Physical Education College, Shandong Normal University PARTICIPANTS： Fifty-five female students were enrolled at Shandong Normal University between September and December in 2005, including 21 students that studied folk dance and 34 students that studied other subjects. The age of the folk dance students averaged （19 ± 1） years and dance training length was （6.0 ± 1.5） years. The students that studied other subjects had never taken part in dance training or other physical training, and their age averaged （22 ± 1） years, body height averaged （162 ± 5） cm, body mass averaged （51 ± 6） kg. All subjects had no prior ear disease or history of other neurological disorders. All students provided informed consent for the experimental project. METHODS： The neural electricity tester, NDI-200 （Shanghai Poseidon Medical Electronic Instrument Factory） was used to examine and record Brainstem Auditory Evoked Potential values of the subjects during silence, as well as to transversally analyze the Brainstem Auditory Evoked Potential values. The electrode positions were cleaned and degreased with soapy water, followed by ethanol. The selected bipolar electrodes were situated on the head： recording electrodes were placed at the Baihui acupoint, and the reference electrode was placed at the mastoid of the measured ear, with grounding electrodes in the center of the forehead. Brainstem Auditory Evoked Potential values were elicited by monaural stimulation of a ＂click＂ though an earphone; the other ear was sheltered by the white noise. The click intensity was 102 db, the stimulation frequency was 30 Hz, the bandpass filters were 1 000-3 000 Hz, the sensitivity was 5 ta V, and a total of 2 000 sweeps were averaged. Waveform identification and analysis： various components of the Brainstem Auditory Evoked Potential values were identified, and the peak latencies and peak-peak values were analyzed. MAIN OUTCOME MEASURES： Latency of Ⅰ , Ⅱ, Ⅲ, Ⅳ, Ⅴ and Peak-Peak Value of Ⅰ, Ⅲ, Ⅴwere measured. RESULTS： Fifty-five subjects were enrolled in the final analysis, without any loss. Compared to the students who studied other subjects ① Ⅰ -Ⅴ peak latencies （PL）： Ⅳ PL of the right ear of the folk dance students was obviously longer （P 〈 0.05）; ② Ⅰ, Ⅲ, V peak-peak values：Ⅰ peak-peak values of the right ear were obviously higher （P 〈 0.05）. CONCUSION： ① PL of the right ear of the folk dance students was obviously longer, which indicates that dancing results in a stronger sensibility to auditory stimuli. ②. Peak-peak values were obviously higher, which indicates that long-term exercise enhances the music senses and synchrony of auditory nerve impulses.

Enhanced auditory evoked potentials in musicians:A review of recent findings

Auditory evoked potentials serve as an objective mode for assessment to check the functioning of the auditory system and neuroplasticity.Literature has reported enhanced electrophysiological responses in musicians, which shows neuroplasticity in musicians. Various databases including Pub Med, Google, Google Scholar and Medline were searched for references related to auditory evoked potentials in musicians from 1994 till date. Different auditory evoked potentials in musicians have been summarized in the present article. The findings of various studies may support as evidences for music-induced neuroplasticity which can be used for the treatment of various clinical disorders. The search results showed enhanced auditory evoked potentials in musicians compared to non-musicians from brainstem to cortical levels. Also, the present review showed enhanced attentive and pre-attentive skills in musicians compared to non-musicians.

Electroencephalogram and brainstem auditory evoked potential in 539 patients with central coordination disorder

BACKGROUND： Electroencephalogram （EEG） and brainstem auditory evoked potential （BAEP） are objective non-invasive means of measuring brain electrophysiology. OBJECTIVE： To analyze the value of EEG and BAEP in early diagnosis, treatment and prognostic evaluation of central coordination disorder. DESIGN, TIME AND SETTING： This case analysis study was performed at the Rehabilitation Center of Hunan Children＇s Hospital from January 2002 to January 2006. PARTICIPANTS： A total of 593 patients with severe central coordination disorder, comprising 455 boys and 138 girls, aged 1-6 months were enrolled for this study. METHODS： EEG was monitored using electroencephalography. BAEP was recorded using a Keypoint electromyogram device. Intelligence was tested by professionals using the Gesell scale. MAIN OUTCOME MEASURES： （1） The rate of abnormal EEG and BAEP, （2） correlation of abnormalities of EEG and BAEP with associated injuries, （3） correlation of abnormalities of EEG and BAEP with high risk factors. RESULTS： The rate of abnormal EEG was 68.6% （407/593 patients）, and was increased in patients who also had mental retardation （P 〈 0.05）. The rate of abnormal BAEP was 21.4% （127/593 patients）. These 127 patients included 67 patients （52.8%） with peripheral auditory damage and 60 patients （47.2%） with central and mixed auditory damage. The rate of abnormal BAEP was significantly increased in patients who also had mental retardation （P 〈 0.01 ）. Logistic regression analysis showed that asphyxia （P 〈 0.05）, jaundice, preterm delivery, low birth weight and the umbilical cord around the neck were closely correlated with abnormal EEG in patients with central coordination disorder, lntracranial hemorrhage, jaundice （P 〈 0.05）, low birth weight and intrauterine infection （P 〈 0.05） were closely correlated with abnormal BAEP in patients with central coordination disorder. CONCLUSION： Central coordination disorder is often associated with abnormal EEG and BAEP. The rate of EEG or BAEP abnormality is positively associated with the size of the brain injury. Asphyxia is a high risk factor for abnormal EEG in central coordination disorder. Jaundice and intrauterine infection are high risk factors for abnormal BAEP in central coordination disorder.

Characteristics of brainstem auditory evoked potential of neonates with mild or moderate hyperbilirubinemia

BACKGROUND： Brainstem auditory evoked potential （BAEP） has been widely used to evaluate the functional integrity and development of injured auditory system and brain, especially to objectively evaluate the function of auditory system and brain stem of very young babies, such as neonates and sick babies. OBJECTIVE： To observe the changes of BAEP of neonates with hyperbilirubinemia, and to investigate the relationship of bilirubin concentration and BAEP. DESIGN： An observation experiment. SETTING： Department of Pediatrics, the 309 Clinical Division, General Hospital of Chinese PLA. PARTICIPANTS： Fifty-eight neonates with mild or moderate hyperbilirubinemia exhibiting jaundice within 24 hours after born, who received the treatment in the Department of Pediatrics, the 309 Clinical Division, General Hospital of Chinese PLA between January 2004 and May 2007, were recruited in this study. The involved neonates, 31 boys and 27 girls, had gestational age of 37 to 46 weeks. They had no history of birth asphyxia, and were scored 8 to 10 points when born. Written informed consents of examination and treatment were obtained from the guardians of the neonates. This study was approved by the Hospital Ethics Committee. According to serum total bilirubin value, the neonates were assigned into 3 groups： low-concentration bilirubin group （n =16）, moderate-concentration bilirubin group （n =27） and high-concentration bilirubin group （n =15）. According to mean daily bilirubin increase, the subjects were sub-assigned into bilirubin rapid increase group （n =39） and bilirubin slow increase group （n = 19）. METHODS： After admission, all the neonates received drug treatment. Meanwhile, their 116 ears were examined with a myoelectricity evoked potential equipment （KEYPOINT） in latency, wave duration, amplitude and wave shape differentiation of each wave of BAEP. BAEP abnormal type was observed and abnormal rate of BAEP was calculated. MAIN OUTCOME MEASURES： ①Abnormal rate and abnormal type of BAEP. ② Latency of waves Ⅰ , Ⅲ and Ⅴ, and wave duration of waves Ⅰ to Ⅲ,Ⅲ to Ⅴ, and Ⅰ to Ⅴ. RESULTS： Fifty-eight neonates with mild or moderate hyperbilirubinemia were involved in the final analysis. ①Abnormal type and abnormal rate of BAEP of neonates with hyperbilirubinemia： Among the 116 ears, unilateral or bilateral waves Ⅰ, Ⅲ,Ⅴ still existed. The latency of waves Ⅰ, Ⅲ and Ⅴ was ＋2.5 s longer than the normal level in 8, 4 and 15 ears, respectively. The wave duration of waves Ⅰ to Ⅲ and waves Ⅲ to Ⅴ was ＋2.5 s longer than the normal level in 6 and 14 ears, respectively. The wave duration of waves Ⅲ to Ⅴ was longer than that of ipsilateral waves Ⅰ to Ⅲ in 24 ears. The latency difference of wave Ⅴ between two ears was larger than 0.4 ms in 31 neonates with hyperbilirubinemia; The amplitude of wave Ⅴ to that of ipsilateral wave 1 was lower than 0.5 in 29 neonates. Totally 52 ears were abnormal, and the abnormal rate was 44.8%. One to two months later, 98% abnormal neonates with hyperbilirubinemia recovered. The abnormal rate in the low-, moderate-, and high-concentration bilirubin groups was 37.5%, 44.4% and 53.3%, respectively. ② Comparison of latency and wave duration of each wave of BAEP： Latency of waves Ⅰ, Ⅲ and Ⅴ, and wave duration of waves Ⅰ to III and Ⅲ to Ⅴ were gradually prolonged in low-, moderate-, and high-concentration bilirubin groups, but significant difference did not exist between two groups （P 〉 0.05）. ③ There were no significant differences in latency of waves Ⅰ, Ⅲand Ⅴ, and wave duration of waves Ⅰ to Ⅲ, Ⅲto Ⅴ and Ⅰ to Ⅴ between bilirubin rapid increase group and bilirubin slow increase group （P 〉 0.05）. CONCLUSION： Auditory acuity and brainstem of neonates with mild or moderate hyperbilirubinemia are damaged to some extent. High-concentration bilirubin causes BAEP abnormality easily. Bilirubin increase and its concentration change are not consistent with nervous lesion degree.

Effect of Acupuncture on the Auditory Evoked Brain Stem Potential in Parkinson's Disease

Under the auditory evoked brain stem potential (ABP) examination, the latent period of V wave and the intermittent periods of III-V peak and I-V peak were significantly shortened in Parkinson's disease patients of the treatment group (N=29) after acupuncture treatment. The difference of cumulative scores in Webster's scale was also decreased in correlation analysis. The increase of dopamine in the brain and the excitability of the dopamine neurons may contribute to the therapeutic effects, in TCM terms, of subduing the pathogenic wind and tranquilizing the mind.……

RELATIONS OF INTRACRANIAL PRESSURE, CREATINE KINASE AND BRAINSTEM AUDITORY EVOKED POTENTIAL IN PATIENTS WITH TRAUMATIC BRAIN EDEMA

We studied the relations of intracranial pressure (ICP),creatine kinase (CK) and bralnstem auditory evoked potential (BAEP) in 44 patients with traumatic brain edema who were admitted to our hospital from June 1990 to February 1991. There were 30 males and 14 females, with age range from 9 to 67 years. The results showed that the abnormal BAEP could reflect the severity of cerebral edema in acute head injury and was related to ICP and serum CK levels. When ICP>30 mmHg (4kPa), the abnormality of BAEP was more obvious than that of the control group (P<0.05); the serum CK levels were also elevated markedly. In patients with ICP over and below 4kPa, the rate of abnormal BAEP was 38.46% and 77.78% respectively (P<0.05). The serum CK level in the normal group or in the group with moderate abnormality of BAEP was significantly different from that in the group with severe abnormality or lack of BAEP (274.8± 98.24 U/L vs 705.3± 364.27 U/L; P<0.001). After treatment, the ICP returned to normal, and the BAEP norm

Normalization of auditory evoked potential and visual evoked potential in patients with idiot savant

Objective To investigate the variations of auditory evoked potentials (AEP) and visual evoked potentials (VEP) of patients with idiot savant (IS) syndrome. Methods Both AEP and VEP were recorded from 7 patients with IS syndrome, 21 mentally retarded (MR) children without the syndrome and 21 normally age matched controls, using a Dantec concerto SEEG 16 BEAM instrument. Results Both AEP and VEP of MR group showed significantly longer latencies (P1 and P2 latencies of AEP, P<0.01; N1 and N2 latencies of VEP, P< 0.01/0.05), lower P2 amplitudes (P<0.01) and higher P3 amplitudes (P<0.01), as compared with normal controls. But none of above mentioned changes was found with IS group. Almost all MR patients (90.1%) presented P4 component in both AEP and VEP, which was also in sharp contrast with its incidence in other 2 groups (IS: 14.3%; normal controls: 9.5%). Conclusion Patients with idiot savant syndrome presented normalized AEP and VEP.

Brainstem auditory evoked potential combined with high resolution cranial base CT can optimize the diagnosis of auditory nerve injury

Purpose:Auditory nerve injury is one of the most common nerve injury complications of skull base fractures.However,there is currently a lack of auxiliary examination methods for its direct diagnosis.The purpose of this study was to find a more efficient and accurate means of diagnosis for auditory nerve injury.Methods:Through retrospectively analyzing the results of brainstem auditory evoked potential(BAEP)and high-resolution CT(HRCT)in 37 patients with hearing impairment following trauma from January 1,2018 to July 31,2020,the role of the two inspection methods in the diagnosis of auditory nerve injury was studied.Inclusion criteria were patient had a clear history of trauma and unilateral hearing impairment after trauma;while exclusion criteria were:(1)severe patient with a Glasgow coma scale score<5 because these patients were classified as severe head injury and admitted to the intensive care unit,(2)patient in the subacute stage admitted 72 h after trauma,and(3)patient with prior hearing impairment before trauma.According to Goodman's classification of hearing impairment,the patients were divided into low/medium/severe injury groups.In addition,patients were divided into HRCT-positive and negative groups for further investigation with their BAEP results.The positive rates of BEAP for each group were observed,and the results were analyzed by Chi-square test(p<0.05,regarded as statistical difference).Results:A total of 37 patients were included,including 21 males and 16 females.All of them were hospitalized patients with GCS score of 6-15 at the time of admission.The BAEP positive rate in the medium and severe injury group was 100%,which was significantly higher than that in the low injury group(27.27%)(p<0.01).The rate of BEAP positivity was significantly higher in the HRCT-positive group(20/30,66.7%)than in the HRCT-negative group(1/7,14.3%)(p<0.05).Twenty patients(54.05%)were both positive for BEAP and HRCT test,and considered to have auditory nerve damage.Six patients(16.22%)were both negative for BEAP and HRCT test,and 10 patients(27.03%)were BAEP-negative but HRCT-positive:all the 16 patients were considered as non-neurological injury.The rest 1 case(2.70%)was BAEP-positive but HRCT-negative,which we speculate may have auditory nerve concussion.Conclusion:By way of BAEP combining with skull base HRCT,we may improve the accuracy of the diagnosis of auditory nerve injury.Such a diagnostic strategy may be beneficial to guiding treatment plans and evaluating prognosis.

Influence of Electroacupuncture on Auditory Evoked Potential Index During Propofol Sedation

Objective： To investigate the influence of electroacupuncture on auditory evoked potential index （AAI） during propofol sedation. Methods： According to propofol effect site concentration, 24 patients for operation were randomly allocated to group 1 （1.0 μg/mL）, group 2 （1. 5μg/mL） and group 3 （2.0 μg/mL）. Propofol was administered intravenously, points Hegu （LI4） and Neiguan （PC6） were electro-acupunctured, and changes in AAI were recorded. Results： AAI significantly rose in all groups during the initial several minutes after electro-acupuncture and significantly fell in group 2 at 20 min after electro-acupuncture（P〈 0.05）.Conclusion： AAI can sensitively reflect pain response during electro-acupuncture and electro-acupuncture can strengthen propofol sedation at its medium concentration.

Can bispectral index or auditory evoked potential index predict implicit memory during propofol-induced sedation?

Background Some patients still suffer from implicit memory of intraoperative events under adequate depth of anaesthesia. The elimination of implicit memory should be a necessary aim of clinical general anaesthesia. However, implicit memory cannot be tested during anaesthesia yet. We propose bispectral index （BIS） and auditory evoked potential index （AEPI）, as predictors of implicit memory during anaesthesia. Methods Thirty-six patients were equally divided into 3 groups according to the Observer＇s Assessment of Alertness/Sedation Score： A, level 3; B, level 2 ;and C, level 1. Every patient was given the first auditory stimulus before sedation. Then every patient received the second auditory stimulus after the target level of sedation had been reached. BIS and AEPI were monitored before and after the second auditory stimulus presentation. Four hours later, the inclusion test and exclusion test were performed on the ward using process dissociation procedure and the scores of implicit memory estimated. Results In groups A and B but not C, implicit memory estimates were statistically greater than zero （P〈0.05）. The implicit memory scores in group A did not differ significantly from those in group B （P〉0.05）. Implicit memory scores correlated with BIS and AEPI （P〈0.01）. The area under ROC curve is BIS〉 AEPI. The 95% cutoff points of BIS and AEPI for predicting implicit memory are 47 and 28, respectively. Conclusions Implicit memory does not disappear until the depth of sedation increases to level 1 of OAA/S score. Implicit memory scores correlate well with BIS and AEPI during sedation. BIS is a better index for predicting implicit memory than AEPI during propofol induced sedation.

Auditory steady-state evoked response in diagnosing and evaluating hearing in infants

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.

Changes in Electroencephalogram Approximate Entropy Reflect Auditory Processing and Functional Complexity in Frogs

Brain systems engage in what are generally considered to be among the most complex forms of information processing. In the present study, we investigated the functional complexity of anuran auditory processing using the approximate entropy（Ap En） protocol for electroencephalogram（EEG） recordings from the forebrain and midbrain while male and female music frogs（Babina daunchina） listened to acoustic stimuli whose biological significance varied. The stimuli used were synthesized white noise（reflecting a novel signal）, conspecific male advertisement calls with either high or low sexual attractiveness（reflecting sexual selection） and silence（reflecting a baseline）. The results showed that 1） Ap En evoked by conspecific calls exceeded Ap En evoked by synthesized white noise in the left mesencephalon indicating this structure plays a critical role in processing acoustic signals with biological significance; 2） Ap En in the mesencephalon was significantly higher than for the telencephalon, consistent with the fact that the anuran midbrain contains a large well-organized auditory nucleus（torus semicircularis） while the forebrain does not; 3） for females Ap En in the mesencephalon was significantly different than that of males, suggesting that males and females process biological stimuli related to mate choice differently.

AN EXPERIMENTAL STUDY OF ELECTROACUPUNCTURE ON AUDITORY IMPAIRMENT CAUSED BY KANAMYCIN IN GUINEA PIGS

Frequency following response(FFR)and auditory brain stem evoked potential response(ABR)were used to determine the auditory acuity in evaluating the effect of electro-acupuncture treatment of kanamycin-induced auditory impairment in guinea pigs.Thesuccinate dehydrogenase(SDH)activity and morphological changes of the inner earreceptors were examined under the light and scanning electron microscope in cochlearspread preparations.The results showed that 1)electro-acupuncture was effective but nosignificant differences were found among the stimulating wave forms;2)Tinggong(SI19),Yifeng(SJ 17),Shenshu(UB 23),Sanyinjiao(Sp 6),Zhubin(K 9)and Waiguan(SJ 5)are all effective acupoints,especially the combination of Tinggong(SI 19),Sanyinjiao(Sp6)and Zhubin(K 9)acupoints;3)improvement in the cochlear function and excitabilityof the cortical and lower auditory center and increase of the mitochondrial SDH activityand energy supply in hair cells might contribute to the mechanism of the treatment.

婴儿分泌性中耳炎的听力学结果分析

目的 探讨226、1 000 Hz鼓室声导抗测试和气-骨导听性脑干反应(ABR)以及畸变产物耳声发射(DPOAE)在诊断低月龄婴儿分泌性中耳炎(OME)中的作用。方法 回顾性分析年龄为1~6个月的119例(192耳)中耳积液患儿(异常组)和66例(132耳)正常婴儿(正常组)的226、1 000 Hz鼓室声导抗测试和气-骨导ABR,以及DPOAE检测结果。结果 (1)OME婴儿,1 000 Hz鼓室声导抗异常图形(As型、B型、C型)有189耳(98.44%),226 Hz鼓室声导抗异常图形(As型、B型、C型)有135耳(70.31%);(2)OME婴儿ABR波Ⅰ潜伏期延长179耳(93.23%),ABR波Ⅴ反应阈中度异常69耳(35.94%)、轻度异常97耳(50.52%)、阈值正常26耳(13.54%),骨导ABR阈值正常164耳(85.42%),阈值轻度异常28耳(14.58%),气-骨导ABR阈值差值变大162耳(84.37%);(3)OME婴儿DPOAE未引出151耳(78.65%)。结论 1 000 Hz声导抗异常、气-骨导ABR阈值差变大、ABR波I潜伏期延长和气导ABR阈值异常对低月龄婴儿中耳积液的诊断有重要参考价值,226 Hz声导抗对部分低月龄婴儿中耳积液的诊断不能提供准确信息。

Binaural masking level difference for pure tone signals

The binaural masking level difference(BMLD)is a psychoacoustic method to determine binaural interaction and central auditory processes.The BMLD is the difference in hearing thresholds in homophasic and antiphasic conditions.The duration,phase and frequency of the stimuli can affect the BMLD.The main aim of the study is to evaluate the BMLD for stimuli of different durations and frequencies which could also be used in future electrophysiological studies.To this end we developed a GUI to present different frequency signals of variable duration and determine the BMLD.Three different durations and five different frequencies are explored.The results of the study confirm that the hearing threshold for the antiphasic condition is lower than the hearing threshold for the homophasic condition and that differences are significant for signals of 18ms and 48ms duration.Future objective binaural processing studies will be based on 18ms and 48ms stimuli with the same frequencies as used in the current study.

THE GENETIC-INDUCED HEARING lOSS CAN BLOCK THE EFFECT OF NOISE TRAUMA IN WAlTZING GUINEA PIG

The waltzing guinea pig may be a good model to investigate if genetic factor can change the sensitivity in noise-induced hearing loss. A total of 34 waltzig guinea pigs were studied and we found that there is no any significant increased sensitivity to noise trauma if the age-induced hearing loss was considered in waltz-ing guinea pig.

Acoustic Trauma of Guinea Pigs Caused by ^(60) Cobalt γ-Ray

Auditory cortical cvokod rcsponse(ACER) and auditory brainstom cvoked response (ABR) were recorded in guinea pigs before and after irradiation of ^(60)Co γ-ray. A single dose of irradiation on head was 90Gy and 70Gy in two groups, respectively. Two h after irradiation. the threshold shift was 12. 5 dB and 9 dB, and the ACER post-irradiation amplitude ex- ceeded the maximum pre-irradiation value by 20% and 37%. Six h after irradiation, the threshold shift increased to 37 dB and the maximum amplitnde decreased to the level of pre-irradiation in 70Gy-group. In another group, right auditory bulla arca was irradiated with a total dose of 45Gy in a course of six fractions/two weeks. Fourteen d after irradiation, the threshold shift of ABR was 118 dB and the latency of wave I was longer. The amplitude-intensity curve was after irradiation. Histological observation using scanning showed that only outer hair- cells in the basal coil of the cochlea were 6 h after irrdiation 50Gy-group. Bul 16 h later, outer, hair cells in all coils of the cochlea were found to be destroyed extensively and inner cells were destroyed slightly. In 45Gy-group, 14 d after irradiation, outer hair cells in all coils of the cochlea were damaged and no inmer hair cell was injured severely.

Impacts of acupuncture on brainstem evoked potentials in patients with primary depression

Objective To observe the impacts of acupuncture on brainstem evoked potentials in the patients with primary depression. Methods Forty cases of primary depression were treated by acupuncture at Baihui （百会 GV 20）, Yinatng （印堂 GV 29）, DazhuT （大椎 GV 14）, bilateral Shenmen （神门 HT 7）, bilateral Taichong （太冲 LR 3）, bilateral Neiguan （内关 PC 6） and SanyTnjiao （三阴交 SP 6）. The needles were retained for 30 min. Acupuncture treatment was given once every two days, three treatments a week. The brainstem auditory evoked potential （BAEP） and visual evoked potential （VEP） were observed in 6 weeks of treatment. The change in Hamilton depression scale （HAMD） score was observed before and after treatment in the depression group. Results After treatment, VEP wave latency was shortened significantly in patients of depression （P〈0.05）, BAEPIII wave latency was shortened significantly （P〈0.05）. The score of HAMD was decreased apparently in the depression group （P〈0.05）. Conclusions The stressability of visual and auditory stimuli in the central nervous system was decreased in the patients of depression. Acupuncture shortens remarkably the brainstem evoked potentials latency in the patients of depression and achieves the effective results in the treatment of primary depression.

Combined monitoring of evoked potentials during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms

Background Neurophysiologic monitoring during surgery is to prevent permanent neurological injury resulting from surgical manipulation. To improve the accuracy and sensitivity of intraoperative neuromonitoring, combined monitoring of transcranial electrical stimulation motor evoked potentials （TES-MEPs）, somatosensory evoked potentials （SSEPs） and brainstem auditory evoked potentials （BAEPs） was attempted in microsurgery for lesions adjacent to the brainstem and intracranial aneurysms. Methods Monitoring of combined TES-MEPs with SSEPs was attempted in 68 consecutive patients with lesions adjacent to the brainstem as well as intracranial aneurysms. Among them, 31 patients （31 operations, 28 of posterior cranial fossa tumors, 3 of posterior circulation aneurysms） were also subjected to monitoring of BAEPs. The correlation of monitoring results and clinical outcome was studied prospectively. Results Combined monitoring of evoked potentials （EPs） was done in 64 （94.1%） of the 68 patients. MEPs monitoring was impossible for 4 patients （5.9%）. No complication was observed during the combined monitoring in all the patients. In 45 （66.2%） of the 68 patients, EPs were stable, and they were neurologically intact. Motor dysfunction was detected by MEPs in 8 patients, SSEPs in 5, and BAEPs in 4, respectively. Conclusions A close relationship exists between postoperative motor function and the results of TES-MEPs monitoring TES-MEPs are superior to SSEPs and BAEPs in detecting motor dysfunction, but combined EPs serve as a safe, effective and invasive method for intraoperative monitoring of the function of the motor nervous system. Monitoring of combined EPs during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms may detect potentially hazardous maneuvers and improve the safety of subsequent procedures.