Coffee improves auditory neuropathy in diabetic mice

Coffee is a widely consumed beverage and has recently received considerable attention for its possible beneficial effects. Auditory neuropathy is a hearing disorder characterized by an abnormal auditory brainstem response. This study examined the auditory neuropathy induced by diabetes and investigated the action of coffee, trigonelline, and caffeine to determine whether they improved diabetic auditory neuropathy in mice. Auditory brainstem responses, auditory middle latency responses, and otoacoustic emissions were evaluated to assess auditory neuropathy. Coffee or trigonelline ameliorated the hearing threshold shift and delayed latency of the auditory evoked potential in diabetic neuropathy. These findings demonstrate that diabetes can produce a mouse model of auditory neuropathy and that coffee consumption potentially facilitates recovery from diabetes-induced auditory neuropathy. Furthermore, the active constituent in coffee may be trigonelline.     

Electrophysiologic assessment of central auditory processing by auditory brainstem responses in children with autism spectrum disorders

In addition to aberrant features in the speech, children with Autism Spectrum Disorder (ASD) may present unusual responses to sensory stimuli, especially to auditory stimuli. We investigated the auditory ability of children with ASD by using Auditory Brainstem Responses (ABR) as they can directly judge both hearing status and the integrity of auditory brainstem pathways. One hundred twenty-one children (71: ASD; M 58/ F 13, mean age; 41.8 months, 50: control group; M 41/ F 9, mean age; 38 months) were included in the study. As compared with the values in the control group, the latency of wave V, wave I-V, and wave III-V inter-peak latencies were significantly prolonged (p<0.05) in the ASD group. The findings indicate that children with ASD have a dysfunction or immaturity of the central auditory nervous system. We suggest any children with prolonged III-V inter-peak latencies, especially high functioning children should be further evaluated for central auditory processing to set up a more appropriate treatment plan.     

Antioxidant Treatments Recover the Alteration of Auditory‐Evoked Potentials and Reduce Morphological Damage in the Inferior Colliculus after Perinatal Asphyxia in Rat

Maturation of the auditory pathway is dependent on the central nervous system myelination and it can be affected by pathologies such as neonatal hypoxic ischemic (HI) encephalopathy. Our aim was to evaluate the functional integrity of the auditory pathway and to visualize, by histological and cellular methods, the damage to the brainstem using a neonatal rat model of HI brain injury. To carry out this morphofunctional evaluation, we studied the effects of the administration of the antioxidants nicotine, melatonin, resveratrol and docosahexaenoic acid after hypoxia‐ischemia on the inferior colliculus and the auditory pathway. We found that the integrity of the auditory pathway in the brainstem was altered as a consequence of the HI insult. Thus, the auditory brainstem response (ABR) showed increased I–V and III–V wave latencies. At a histological level, HI altered the morphology of the inferior colliculus neurons, astrocytes and oligodendricytes, and at a molecular level, the mitochondria membrane potential and integrity was altered during the first hours after the HI and reactive oxygen species (ROS) activity is increased 12 h after the injury in the brainstem. Following antioxidant treatment, ABR interpeak latency intervals were restored and the body and brain weight was recovered as well as the morphology of the inferior colliculus that was similar to the control group. Our results support the hypothesis that antioxidant treatments have a protective effect on the functional changes of the auditory pathway and on the morphological damage which occurs after HI insult.     

Auditory brainstem responses in the aged cat

Auditory brainstem responses (ABRs) were compared in young adult and aged cats. Mean thresholds for click-evoked ABRs were greater in the aged cats. Clicks normalized to 15 and 30 dB above individual thresholds at rates of 10, 20, 50 and 100/sec evoked ABRs with similar latencies and central conduction times in both groups. Background noise at equal intensity for all cats completely suppressed ABRs evoked by clicks 30 dB above threshold in 2/3 of the young but none of the old cats. As rise time of a 25 msec noise burst at equal intensity for all cats increased 1, 2, 5, and 10 msec, latency of wave 4 increased more for the old cats than for the young. Summed monaural ABRs from both ears were greater than binaural ABRs for waves 4 and 5 in both groups. These data indicate peripheral auditory dysfunction in aged cats but little abnormality in auditory brainstem transmission with click intensity normalized for ABR threshold.     

健康成人听觉中潜伏期反应研究

报告２２名（４４只耳）健康成人听觉中潜伏期反应（ＭＬＲ）和听觉脑干反应（ＡＢＲ）测试结果，ＭＬＲ由Ｎ１、Ｐ１和Ｎ２三个波构成，Ｐ１波在双颞叶呈对称性分布，颅顶区波幅最高，ＭＬＲ不能完全代替ＡＢＲ，但在颞叶、额叶皮层病损中有特殊意义。     

新生儿高胆红素血症听觉脑干电反应的观察

目的:探讨高胆红素血症对新生儿听觉和中枢神经系统的损害程度。方法:采用日本产的MEB-7102型诱发电位仪检测新生儿高胆红素血症60例。结果:听觉脑干电反应的异常率为70％。结果显示新生儿高胆红素血症主要以中脑下部损害为主。结论:听觉脑干电反应有早期了解听通道损害的价值,持续异常则预后不佳。     

GFAP aggregates in the cochlear nerve increase the noise vulnerability of sensory cells in the organ of Corti in the murine model of Alexander disease

Outer hair cell (OHC) loss in the auditory sensory epithelium is a primary cause of noise-induced sensory-neural hearing loss (SNHL). To clarify the participation of glial cells in SNHL, we used an Alexander disease (AxD) mouse model. These transgenic mice harbor the AxD causal mutant of the human glial fibrillary acidic protein (GFAP) under the control of the mouse GFAP promoter. It is thought that GFAP aggregates compromise the function of astrocytes. In the auditory pathway, the formation of GFAP aggregates was observed only in GFAP-positive cells of the cochlear nerve. The presence of GFAP aggregates did not change auditory function at the threshold level. To assess the change in vulnerability to auditory excitotoxicity, both transgenic and control mice were treated with intense noise exposure. Auditory threshold shifts were assessed by auditory brainstem responses (ABR) at 1 and 4 weeks after noise exposure, and OHC damage was analyzed by quantitative histology at 4 weeks after exposure. Transgenic mice showed more severe ABR deficits and OHC damage, suggesting that cochlear nerve glial cells with GFAP aggregates play a role in noise susceptibility. Thus, we should focus more on the roles of cochlear nerve glial cells in SNHL.     

Auditory nerve,brainstem and cortical response correlates of learning capacity

An attempt has been made in this study to determine whether auditory nerve, brainstem (ABR) and cortical auditory evoked responses differ between various groups defined with respect to their intellectual ability. Seventy-seven (77) children, male and female in the same age range were divided according to learning ability and IQ scores into three groups: border-line retardates (R), normals (N) and gifted (G). These groups also demonstrated differences in behavioral tests: draw a person test, reaction-time test, audio-visual integration test and audio-visual cross-modality test. The “R Group” performed behaviorally at the lowest level and the “G Group” performed at the same or at a somewhat higher level than the “N Group”. Analysis of variance for the latency and amplitude parameters of the brainstem (ABR) and cortical auditory averaged evoked responses among the behaviorally defined groups showed that the main differences were in the amplitude parameters, reaching significance in the ABR response. Latency differences among the groups were identical in the ABR responses and did not reach significance in the cortical response. Rate functions did not expose other differences between the groups. Many of these electrophysiological measures were correlated with the behavioral measures.     

Auditory-evoked masseter inhibitory reflex

We aimed to investigate auditory-evoked masseter inhibitory reflex and discuss possible auditory-trigeminal pathways in brainstem. Our study population consisted of 21 healthy volunteers (age-matched 7 males and 14 females). Bilateral electrical blink reflex (BR), auditory blink reflexes (ABR) and electrical MIR (MIR) were studied. After obtaining normal potentials, auditory MIR (AMIR) was studied. Electrical blink reflexes had two components as R1 and R2, and ABR had one evoked potential in all volunteers. There was no significant difference between gender, nor between right- and left-sided BR and ABR. The mean latency of ABR responses were shorter than latencies of R2 phase of BR (p = 0.013 for left-sided responses, p = 0.035 for right-sided responses). Electrical stimulation revealed two suppression periods (SP1 and SP2) in MIR responses bilaterally in all volunteers. Auditory stimulation evoked typical two suppression periods only in 11 subjects (5 males, 6 females). The mean latency of SP1 component of AMIR was significantly longer than those of MIR bilaterally in both males and females, while the SP2 component had a shorter onset. The durations of SP1, SP2 and total SP were always shorter than those obtained in MIR with smaller degree of suppressions. None of the MIR or AMIR responses showed significance difference between sexes. We assume that auditory-evoked MIR might share the similar interneurons as with other electrical or nociceptive stimulation, which connects cochlear-trigeminal neurons via pontine reticular system to premotor area for masseter muscle.     

Detection and differentiation of sensorineural hearing loss in mice using auditory steady-state responses and transient auditory brainstem responses

Sensorineural hearing loss (SNHL) comprises hearing disorders with diverse pathologies of the inner ear and the auditory nerve. To date, an unambiguous phenotypical characterization of the specific pathologies in an affected individual remains impossible. Here, we evaluated the use of scalp-recorded auditory steady-state responses (ASSR) and transient auditory brainstem responses (ABR) for differentiating the disease mechanisms underlying sensorineural hearing loss in well-characterized mouse models. We first characterized the ASSR evoked by sinusoidally amplitude-modulated tones in wild-type mice. ASSR were robustly elicited within three ranges of modulation frequencies below 200 Hz, from 200 to 600 Hz and beyond 600 Hz in most recordings. Using phase information we estimated the apparent ASSR latency to be about 3 ms, suggesting generation in the auditory brainstem. Auditory thresholds obtained by automated and visual analysis of ASSR recordings were comparable to those found with tone-burst evoked ABR in the same mice. We then recorded ASSR and ABR from mouse mutants bearing defects of either outer hair cell amplification (KCNQ4-knockout) or inner hair cell synaptic transmission (Bassoon-mutant). Both mutants showed an increase of ASSR and ABR thresholds of approximately 40 dB versus wild-type when investigated at 8 weeks of age. Mice with defective amplification displayed a steep rise of ASSR and ABR amplitudes with increasing sound intensity, presumably reflecting a strong recruitment of synchronously activated neural elements beyond threshold. In contrast, the amplitudes of ASSR and ABR responses of mice with impaired synaptic transmission grew very little with sound intensity. In summary, ASSR allow for a rapid, objective and frequency-specific hearing assessment and together with ABR and otoacoustic emissions can contribute to the differential diagnosis of SNHL.     

Limitation of Conventional Audiometry in Identifying Hidden Hearing Loss in Acute Noise Exposure

PurposeThe concept of hidden hearing loss can explain the discrepancy between a listener''s perception of hearing ability and hearing evaluation using pure tone audiograms. This study investigated the utility of the suprathreshold auditory brainstem response (ABR) for the evaluation of hidden hearing loss in noise-exposed ear with normal audiograms.Materials and MethodsA total of 15 patients (24 ears) with normal auditory thresholds and normal distortion product otoacoustic emissions were included in a retrospective analysis of medical records of 80 patients presenting with histories of acute noise exposure. The control group included 12 subjects (24 ears) with normal audiograms and no history of noise exposure. Pure tone audiometry and suprathreshold ABR testing at 90 dB peSPL were performed. The amplitudes and latencies of ABR waves I and V were compared between the noise-exposed and control groups.ResultsWe found no significant difference in the wave I or V amplitude, or the wave I/V ratio, between the two groups. The latencies of ABR wave I, V, and I-V interpeak interval were compared, and no significant intergroup difference was observed.ConclusionThe results suggest that either hidden hearing loss may not be significant in this cohort of patients with acute noise exposure history, or the possible damage by noise exposure is not reflected in the ABRs. Further studies are needed to inquire about the role of ABR in identification of hidden hearing loss.     

脑干听觉反应（ABR）在青少年精神分裂症和孤独症中的应用

目的：探讨青少年精神分裂症（AS）和孤独症儿童（AC）在脑干听觉反应（ABR）检测中的特点。方法：应用美国Nicolet Bravo脑电生理仪及Click短声刺激,测查32例AS和30例孤独症（AC）和40名健康儿童（NC）的ABR。结果：AS组、AC组及NC组在绝对潜伏期波Ⅲ（Oz脑区）,绝对波幅波Ⅲ（Oz脑区）,波V（Oz脑区）上有差异极显著性（P〈0．01）。与NC组和AS组相比,绝对潜伏期波Ⅲ（Oz脑区）上,AC组延迟于NC组和AS组（P〈0．01）。波幅分析所见,绝对波幅Ⅲ（Oz脑区）AC组低于NC组和AS组（P〈0．01）;绝对波幅波V（Oz脑区）AC组也低于NC组和AS组。AS组与NC组比较,差异未达显著性（P〉0．05）。结论：ABR对临床辅助诊断AC和AS有初步参考价值。     

The development of auditory event related potentials in the rhesus monkey (Macaca mulatta)

Auditory event related potentials were recorded from neonatal, 3‐month, and 3‐year old rhesus monkeys. Auditory brainstem evoked responses (ABRs) were reliably recorded at all ages. ABR latencies decreased with age. Age effects were greater the more centrally generated the wave. Wave I amplitude decreased with age, Wave II increased, and Wave IV remained about the same. Stimulus rate effects were greater in neonates than older monkeys. Stimulus frequency also affected the ABR, but not differentially as a function of age. Recording montage had a significant effect on the recorded waveform. Wave I tended to be larger in amplitude in horizontal recordings and front–back recordings, while the later waves were relatively more prominent in more vertical montages. Middle latency evoked responses and late potentials were less reliably recorded than the ABR. Their reproducibility improved with age. Auditory event related potentials are promising measures of auditory function for research requiring nonhuman primate models of the developing human. © 1999 John Wiley & Sons, Inc. Dev Psychobiol 34: 37–56, 1999     

Noise-induced tinnitus: auditory evoked potential in symptomatic and asymptomatic patients

OBJECTIVES:

We evaluated the central auditory pathways in workers with noise-induced tinnitus with normal hearing thresholds, compared the auditory brainstem response results in groups with and without tinnitus and correlated the tinnitus location to the auditory brainstem response findings in individuals with a history of occupational noise exposure.

METHOD:

Sixty individuals participated in the study and the following procedures were performed: anamnesis, immittance measures, pure-tone air conduction thresholds at all frequencies between 0.25–8 kHz and auditory brainstem response.

RESULTS:

The mean auditory brainstem response latencies were lower in the Control group than in the Tinnitus group, but no significant differences between the groups were observed. Qualitative analysis showed more alterations in the lower brainstem in the Tinnitus group. The strongest relationship between tinnitus location and auditory brainstem response alterations was detected in individuals with bilateral tinnitus and bilateral auditory brainstem response alterations compared with patients with unilateral alterations.

CONCLUSION:

Our findings suggest the occurrence of a possible dysfunction in the central auditory nervous system (brainstem) in individuals with noise-induced tinnitus and a normal hearing threshold.     

Precortical filtering and selective attention: an evoked potential analysis

Attention-related changes in the human auditory brainstem response and the short-latency somatosensory evoked potential (SLSEP) were demonstrated in separate experiments. In Experiment 1, ABRs were recorded during conditions in which subjects awaited the presentation of either auditory or somatosensory target stimuli. In Experiment 2, median nerve SLSEPs were recorded in a similar task context. Analyses of ABR and SLSEP component amplitudes and latencies revealed that the auditory nerve (wave II) and rostral brainstem (wave V) components of the ABR, and the cervical component (N12) of the SLSEP, were facilitated when attention was directed toward stimuli that were presented in the same sensory modality and receptive field as the EP-eliciting stimuli. These results suggest that central mechanisms can modulate the transmission of auditory and somatosensory information at an early, precortical stage and that these mechanisms play a role in auditory and somatosensory selective attention.     

Evaluation of asymptomatic central neuropathy in type I diabetes mellitus

OBJECTIVES: Diabetic neuropathy is recognized as the most common clinical picture of nervous system disorders caused by diabetes mellitus (DM). Although peripheral and autonomic nervous system involvements are frequently encountered, there exists a few data about the incidence of central diabetic neuropathies. Central nervous system degeneration is a well known pathology in diabetic patients in the long term. It is possible to reveal central nervous system involvement at the early stages by using evoked potentials (EP). The aim of this study is to evaluate the auditory, visual and sensorial abnormalities in type I diabetic patients, who also have normal nerve conduction studies, with somatosensory, brainstem auditory and visual EP studies (SEP, VEP BAEP); to determine the frequency of these abnormalities and to investigate the relationship between other variables such as age, gender, duration of the diabetes and degree of the metabolic control. PATIENTS AND METHODS: A total of 36 asymptomatic type I DM children, ages ranging between 6-17 (mean age 11 +/- 3.24) taking insulin treatments were included in this study. Control group was made up of healthy children. EPs were evaluated and comparisons were made between the two groups. RESULTS: In a large group of diabetic children (47.2%), independent from parameters such as age, gender, glycemic control degree, auditory and visual deficits, retinopathy, joint movement limitation; but dependent on the peripheral SEP pathologies and disease duration there were central electrophysiological disturbances. In 13 (36.1%) of the patients SEP pathologies; in 9 (25%) of the patients VEP pathologies and in 14 (38.9%) of the patients BAEP pathologies were detected. Conclusion: Besides independent from peripheral pathologies, central nervous system involvement could also be observed in diabetic children. EP changes can be detected in asymptomatic patients that would be a predictor of future symptoms.     

Effect of the ketamine/xylazine anesthetic on the auditory brainstem response of adult gerbils

The auditory brainstem response (ABR) is a test widely used to assess the integrity of the brain stem. Although it is considered to be an auditory-evoked potential that is influenced by the physical characteristics of the stimulus, such as rate, polarity and type of stimulus, it may also be influenced by the change in several parameters. The use of anesthetics may adversely influence the value of the ABR wave latency. One of the anesthetics used for ABR assessment, especially in animal research, is the ketamine/xylazine combination. Our objective was to determine the influence of the ketamine/xylazine anesthetic on the ABR latency values in adult gerbils. The ABRs of 12 adult gerbils injected with the anesthetic were collected on three consecutive days, or a total of six collections, namely: pre-collection and A, B, C, D, and E collections. Before each collection the gerbil was injected with a dose of ketamine (100 mg/kg)/xylazine (4 mg/kg). For the capture of the ABR, 2000 click stimuli were used with rarefaction polarity and 13 stimuli per second, 80 dBnHL intensity and in-ear phones. A statistically significant difference was observed in the latency of the V wave in the ABR of gerbils in the C and D collections compared to the pre-, A and E collections, and no difference was observed between the pre-, A, B, and E collections. We conclude that the use of ketamine/xylazine increases the latency of the V wave of the ABR after several doses injected into adult gerbils; thus, clinicians should consider the use of this substance in the assessment of ABR.     

无尾两栖类蟾蜍和鸣禽锡嘴雀听觉中枢及其神经通赂的比较研究

本研究采用HRP示踪技术对无尾两栖类蟾蜍（Bufogargarizans）和鸣禽锡嘴雀（Ooccothraustescoccothraustes）从外周到听觉中枢的通路逐级进行了追踪比较研究.结果表明（1）无尾两栖类内耳囊听觉神经纤维上行投射到延髓同侧的背侧前庭核,它是听觉上行通路的第一级中枢,由此核中继后再投射到上橄榄核．以对侧为主;上橄榄核再发出纤维投射到中脑同侧的半环隆枕,后者是第三级中枢,此结果说明：无尾两栖类从外周到中脑听觉中枢的神经通路已较完整地形成;（2）鸣禽锡嘴雀的耳蜗听神经上行投射到听觉通路的第一级中队即延脑同侧的前庭外则核和角核,角核又发出纤维通过外侧丘系直接投射到对侧的中脑背外侧核．说明鸣禽鸟除了具备两栖类的听觉中枢及神经通路外．已进化形成独特的听觉神经通路即延脑的角核至中脑的背外侧核。     

Two-dimensional spectral processing of sequential evoked potentials

The processing of sequential evoked potentials (EPs) is investigated using two-dimensional processing techniques. Two-dimensional EP arrays or images are formed by stacking sequential recordings. Processing is accomplished in the frequency domain by 2-D low-pass filtering using Gaussian filters. Auditory brainstem responses (ABRs), which are the early auditory EPs, are used to investigate the effects of the 2-D filtering on real data. Gaussian filtering improves signal-to-noise ratios by reducing high frequency noise effectively in both intra-EP and inter-EP dimensions. Applications to intra-operative monitoring are simulated with real ABR data.     

弱智儿童听觉中潜伏期反应和40Hz相关电位

目的：对弱智儿童４０Ｈｚ听觉相关电位（４０ＨｚＡＥＲＰ）、听觉中潜伏期反应（ＭＬＲ）和听性脑干反应（ＡＢＲ）检测结果进行比较和评估。方法：在作过ＡＢＲ测试的基础上，对６５例（１３０耳）弱智儿童和３０例（６０耳）正常儿童记录４０ＨｚＡＥＲＰ和ＭＬＲ，对两组各项结果进行比较。结果：弱智组４０ＨｚＡＥＲＰ和ＭＬＲ波形出现率在２０ｄＢ（ｎＨＬ）声强刺激时明显低于正常组（Ｐ＜０．００１）；４０ＨｚＡＥＲＰ反应阈较正常儿童增高（Ｐ＜０．０１）；弱智组ＭＬＲ波潜伏期较正常儿稍延长；ＭＬＲ各波振幅较正常组明显降低（Ｐ＜０．０５）。４０ＨｚＡＥＲＰ检测弱智组的波形出现率、反应阈值等与正常组儿童的差异小于ＡＢＲ。结论：弱智组平均听力较正常儿童差；４０ＨｚＡＥＲＰ在评价弱智儿童听力时敏感性比ＡＢＲ高，更能检测出患者存在的低频残余听力