Rapid Increase in Neural Conduction Time in the Adult Human Auditory Brainstem Following Sudden Unilateral Deafness

Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.     

Hearing in Noise Test Brazil: standardization for young adults with normal hearing

IntroductionIndividuals with the same ability of speech recognition in quiet can have extremely different results in noisy environments.ObjectiveTo standardize speech perception in adults with normal hearing in the free field using the Brazilian Hearing in Noise Test.MethodsContemporary, cross-sectional cohort study. 79 adults with normal hearing and without cognitive impairment participated in the study. Lists of Hearing in Noise Test sentences were randomly in quiet, noise front, noise right, and noise left.ResultsThere were no significant differences between right and left ears at all frequencies tested (paired t − 1 test). Nor were significant differences observed when comparing gender and interaction between these conditions. A difference was observed among the free field positions tested, except in the situations of noise right and noise left.ConclusionResults of speech perception in adults with normal hearing in the free field during different listening situations in noise indicated poorer performance during the condition with noise and speech in front, i.e., 0°/0°. The values found in the standardization of the Hearing in Noise Test free field can be used as a reference in the development of protocols for tests of speech perception in noise, and for monitoring individuals with hearing impairment.     

关于生化自动分析仪噪音核查和反应限核查的几点讨论

生化自动分析仪在进行噪音核查和反应限核查之前，均已完成线性核查，已确定线性反应区，从吸光度-时间回归线计算出每分钟吸光度变化速度（△A／min）。在此基础上进行噪音核查（Noise Check）和反应限核查（Reaction Limit Check）。     

舒血宁注射液治疗突发性耳聋的疗效评价

目的：观察舒血宁注射液治疗突发性耳聋的疗效。方法：用舒血宁注射液治疗60例突发性耳聋，金纳多注射液作为对照。结果：舒血宁注射液，治疗突发性耳聋总有效率为94．3％，其中痊愈率114％；显效率45．7％；有效率37.1％，与进口金纳多注射液无明显差别。结论：舒血宁注射液是治疗突发性耳聋有效、安全、经济的新药物。     

乡镇中,小学教室噪声卫生防护距离的研究

本文对乡镇中，小学的交通噪声进行了调查研究，结果表明，在９：００～１６：４５时间内，中学的Ｌｅｑ值为８０ｄＢ（Ａ），Ｌ５０为７２ｄＢ（Ａ），小学的Ｌｅｑ值为８０５ｄＢ（Ａ），Ｌ５０为７３ｄＢ（Ａ）。文章还对不同距离的噪怕衰减情况进行统计分析，并制订出乡镇中，小学教室内噪声不超过５０ｄＢ（Ａ）防护距离为１２０米，不超过４５ｄＢ（Ａ）防护距离为２２０米。     

一种具有高信噪比的脉搏波光电传感器的研制

目的：探讨研制一种生理信号光电传感器。方法：利用光电传感器检测通过指端毛细血管后的光强度的变化，将光信号转换成电信号，再经过电信号1/V转换、放大、滤波处理。结果：获得了清晰稳定的指端容积脉搏波。结论：高信噪比的光电传感器可用作于临床监测和生理信号分析处理系统。     

Isolated and combined effects of prolonged exposures to noise and whole-body vibration on hearing,vision and strain

Summary This study was carried out in order: (1) to examine the effects of isolated and combined prolonged exposures to noise and whole-body vibration on hearing, vision and subjectively experienced strain, and (2) to check the combined effects with repeated exposures. Six male subjects were exposed twice to noise (N) at 92 dBA, whole-body vibration (V) in the Z-axis at 4 Hz and 1.0 ms^–2 rms, and noise and vibration (NV) for 90 min with each condition. Temporary threshold shifts of hearing (TTS) and their integrals (ITTS) were measured at 4, 6, 10, and 12 kHz. Visual acuity was examined by means of a very sensitive test. Cross-modality matching (CMM) of the handgrip force was used to judge the subjectively experienced strain. NV induced a clear tendency of higher TTS and ITTS than N, with several significant differences most pronounced at 10 kHz. With repeated exposures, the effect of NV decreased, while the reactions to N and V remained unchanged. The individual reactions to NV differed. The influence of the duration of exposures on vision depended on the condition; N caused time-dependent changes, whereas V did not. CMM-data increased with the duration of the exposure during V and NV. N was generally judged to be more straining than V; NV caused higher strain than V during the first 30 min of exposure only. Correlations between different effects suggest certain links between them. Additionally, less motivation — daily obtained by a questionnaire — often correlated with higher ITTS during N and NV. The results also illustrate the combined effects on the individual susceptibility, repetition of exposure, the kind of response, and, possibly, the actual psychic state.Abbreviations CMM cross-modality matching - MVC maximum voluntary contraction force - N exposure condition: noise level 92dBA, no whole-body vibration - NV exposure condition: combined exposure to noise with a level of 92 dBA and wholebody vibration with 4 Hz, 1 ms^–2 rms - V exposure condition: whole-body vibration with 4 Hz, 1 ms^–2 rms - TTS temporary threshold shift - ITTS integral of temporary threshold shift - WBV whole-body vibration in the common sense This work was done in the Temporary International Research Team on Combined Effects of Noise and Vibration of the Council of Mutual Economic Assistance of the Socialist Countries. The authors gratefully acknowledge the help and assistance of L.-M. Brumm, Y. Bening, M. Godau, G. Weber, and R. Vizcaino.     

外伤性截瘫合并耳聋11例临床分析

初步分析了11例外伤性截瘫合并耳聋患者,指出外伤性截瘫多有慢性肾功能不全、肾性贫血等并发症。这些并发症对耳聋的发生有一定的影响,但长时间或反复使用耳毒性药物是一个不可忽视的重要因素。作者对此提出了预防耳聋的一些具体措施,可供临床参考或借鉴。     

Characterization and prediction of gradient acoustic noise in MR imagers

Gradient acoustic noise has been measured and characterized for an epoxy-potted, shielded gradient assembly in a 1.5 T MRI system. Noise levels vary by 10 dB or more as a function of longitudinal position in the scanner and reflect the pattern of forces applied to the gradient assembly. The noise level increases slightly (1–3 dB) with a patient in the scanner. The spectrum of the noise is similar (but not identical) to the spectrum of the input signal. A gradient-pulse-to-acoustic-noise transfer function was obtained by using a white noise voltage input to the gradient system. The transfer function enabled us to accurately predict acoustic noise output for a pulse sequence consisting of a series of trapezoidal pulses on a single axis and for a clinical fast spin echo sequence with gradients present on all three axes.