152^mm加农炮对听器损伤的调查

对参加实战的××式１５２ｍｍ加农炮兵撤出战斗后４个月的４７名９４耳进行了听器损伤的调查，结果表明耳聋症状发病率为２４．５％（以耳计，下同）；耳鸣发病率为１９．２％，多为低音调间歇性耳鸣。鼓膜内陷发病率为６６．０％。ＰＴＡ有改变者为１２．８％，高频听力损失（ＨＦ）为３６．２％。且以６０００Ｈｚ受损最明显，占受损耳的８７．０％。分析了４７名１５２ｍｍ加农炮兵听器损伤较轻的原因主要是发射炮弹时个人对耳的防护较好。     

丹参对低气压环境下噪声性听器损伤的防护作用及机理研究

目的探讨丹参对模拟低气压环境下豚鼠噪声性听器损伤的防治作用及其机理。方法48只健康豚鼠随机分为低气压噪声暴露1d及7d两大组,又各分为正常对照组、阳性对照组、丹参治疗组及防治组。后3组均置于模拟高原5500m低气压环境,110dBSPL白噪声刺激;防治组和治疗组分别于造模前3天和出舱当天开始每日肌肉注射丹参注射液(1.3mlkg)。然后检测各组的听性脑干反应(ABR)反应阈,观察耳蜗铺片的形态学改变,检测血清丙二醛(MDA)、超氧化物歧化酶(SOD)和血粘度的变化,并进行统计学比较。结果出舱后各组均有不同程度ABR阈移,暴露7d组较1d组重,以4kHz阈移明显。随出舱时间延长阈移减轻,暴露7d出舱14d后,治疗组和防治组与阳性对照组比较,各观察指标均有统计学差异(P<0.05),形态学改变与听力变化一致。治疗组和防治组间无显著差异。血清MDA浓度随暴露时间的延长而增加,防治组显著低于阳性对照组及治疗组(P<0.05),治疗组于7d及14d时亦低于阳性对照组(P<0.05);血清SOD活性则随暴露时间延长而下降;用药的两组SOD均高于阳性对照组。全血粘度值阳性对照组明显升高,暴露前用药可减轻血粘度的上升而且恢复较快。结论丹参对低气压噪声环境下的听器损伤具有一定的防治效果,可能与其改善微循环和血液流变学特性、抗氧化自由基作用,从而减轻低气压噪声暴露后的氧化损伤有关。     

葛根素对急性低气压环境下噪声性听器损伤的防治作用

目的探讨葛根素对模拟急性低气压环境下噪声性听器损伤的防治作用.方法将60只听力正常豚鼠随机分为正常组、阳性对照组、葛根素防治组和葛根素治疗组.后3组置于模拟高原海拔5 500 m低气压环境,130 dB SPL白噪声持续刺激8小时;防治组和治疗组每日腹腔注射葛根素注射液(150 mg/kg).观察各组的听性脑干反应(ABR)反应阈、耳蜗形态学改变、血液流变学和血清丙二醛(MDA)、超氧化物岐化酶(SOD)含量的变化.结果出舱后8小时,各组ABR阈移最大,对照组、防治组在1 kHz的阈移分别为33.67±5.40、26.50±4.76 dB,在8 kHz的阈移分别为59.33±5.20、48.67±4.70 dB(P＜0.01);高频听力损失较低频严重(P＜0.01).以后各组ABR阈移逐渐恢复,给药两组恢复程度均较对照组明显(P＜0.01).形态学改变与听力变化一致.防治组血清MDA含量显著低于对照组,用药的两组血清SOD均高于对照组.对照组血液流变学全血粘度值明显升高,与用药两组比较有显著性差异.结论葛根素对急性低气压环境下的听器损伤具有一定的防治效果,可能与其改善微循环和血液流变学特性、抗氧化自由基的作用有关.     

听器冲击伤发生机制研究现状与展望

冲击波由时相交替的超压和负压组成。本综述着重介绍了冲击波超压和负压对听器的致伤机制及其影响因素，并对今后的研究方向进行展望。     

内耳色素与爆震性听损伤

目的 探讨内耳色素与爆震性听损伤的关系。方法 选用豚鼠４８只,分为：白化豚鼠爆震组,杂色豚鼠爆震组,正常对照组。爆震前及爆震后６小时、１、２、７、１４、２１天测定Ａ、Ｂ组豚鼠ＡＢＲ阈值。处死豚鼠做耳蜗铺片、耳蜗树脂包埋半薄切片、耳蜗扫描电镜制样,观察耳蜗内色素及耳蜗损伤情况。结果 光镜下杂色豚鼠可见耳蜗内色素颗粒,而白化豚鼠未见。爆震后白化豚鼠听力损伤比杂色豚鼠严重,其听力恢复亦较杂色豚鼠慢。爆震     

噪声性听损伤的微循环研究及其临床意义

本文综述近年来有关噪声与内耳血流研究的进展,探讨噪声对耳微循环的影响,观察内耳生理、生化及新陈代谢功能的变化,为临床寻找合理的治疗途径提供参考。     

外周听器损伤所致听觉中枢改变的研究进展

耳蜗核、上橄榄核复合体、外侧丘系、下丘共同组成听觉脑干中枢.下丘是耳蜗与大脑之间听觉信号传输的重要中转站,解剖位置恒定,易于定位和进行电生理记录,是研究皮层下听觉中枢功能的重点.本文拟就正常下丘神经元对纯音刺激的反应特点,以及外周听器损伤后下丘神经元的生理学改变和神经递质改变等研究进展进行综述.     

新生儿多种听损伤高危因素共存时的听性脑干反应特征分析

目的探讨新生儿高胆红素血症与缺氧缺血性脑病(hypoxic—ischemic encephalopathy，HIE)、极低出生体重(very low—birth weight，VLBW)分别或同时存在时的听性脑干反应(auditory brainstem response，ABR)特点，为早期治疗干预提供参考。方法299例(598耳)高危新生儿分为单纯高胆红素血症组、单纯：HIE组、高胆红素血症 HIE组、高胆红素血症 VLBW组、HIE VLBW组、高胆红素血症 VLBW HIE6组，对每组患儿予ABR检测。结果当新生儿高胆红素血症与HIE、VLBW三种高危因素同时存在时，其异常发生率、重度异常发生率、平均反应阈均较单纯高胆红素血症和单纯HIE显著提高，异常耳中的ABR各波缺失率、反应阈增高的发生率同样亦存在显著增高的现象。结论当新生儿高胆红素血症与缺氧缺血性脑病、极低出生体重同时存在时，听损伤的几率相应增加，听损伤的程度也随之加重。此类患儿更应列为及早干预、重点随访的对象。     

听器冲击伤诊断、治疗和防护研究现状与展望

听器在遭受冲击波暴露时极易受到损害。由于听器冲击伤不仅发生在战争时期 ,而且在和平时期的军事训练和演习中 ,也有较高发生率 ,所以其诊断、治疗和防护是军事医学研究的重点之一。外耳冲击伤其临床表现和治疗与机体其它部位同类伤基本相同[1] 。通常所说的听器冲击伤 ,一般指中耳伤和内耳伤。本文将就二十多年来有关中耳和内耳冲击伤的诊断、治疗和防护等方面的主要研究进展综述如下。1　听器冲击伤的诊断1.1　听器严重受损的表现 :①听力明显减退甚至完全丧失 ;②鼓膜完全穿孔或接近完全穿孔 ;③听骨链损伤 ;④伴有严重眩晕或平衡失调。…     

Influence of acoustic deprivation on recovery of hair cells after acoustic trauma

The purpose of this study was to investigate how the recovery of the cochlea, after acoustic trauma, might be influenced by acoustic stimulation or deprivation. In anaesthetized adult chinchillas, both ears were simultaneously exposed to a traumatizing acoustic stimulus (2 kHz tone, at 117 dB SPL for 15 min). Probe microphones positioned in both bullae were used to ensure identical exposure to the two ears; this was important because the experiment relies on within-animal controls. Cochlear action potential thresholds across frequency (CAP audiograms) were used to verify the similarity of threshold shifts to the two ears. Immediately following, a unilateral ossiculectomy was performed which resulted in one cochlea being acoustically deprived during the recovery period, whilst the other was not. In groups of animals with recovery periods of 1, 3, 6 and 12 weeks, both the acoustically deprived and the normally stimulated cochleas were examined with scanning electron microscopy. To quantify hair cell damage, we used a damage scale based on stereociliar integrity; for each cochlea, a standard region 5.5–8.5 mm from the apex was studied in detail. We found that after acoustic trauma, hair cell damage to the cochlea which is deprived of sound during the recovery period, is significantly greater compared with that in the normally stimulated, contra-lateral cochlea. Our results suggest that mechanical activation of the inner ear acts to inhibit long-term degenerative processes, or influence repair of partially damaged hair cells.     

The protective effects against noise trauma by sound conditioning in rats

Objective To investigate the protective effects of sound conditioning against subsequent high-level noise trauma in rats. Method Rats were exposed to a 4 kHz octave band noise at 95 dB SPL for 10 hours, then to a traumatic exposure dose (105 dB SPL for 13 hours) delivered 12h later. Control animals were exposured to the traumatic dose only. ABR thresholds were obtained before and after noise exposure. Result Animals that had been sound conditioned demonstrated less ABR threshold shift compared to those that had not. Conclusion Moderate level sound exposure appears to have a toughening effect on the rat cochlea (or"conditioning") leading to de-creased hearing loss from subsequent traumatic exposure.     

Otoacoustic emissions and persistent tinnitus after acute acoustic trauma

OBJECTIVES: To follow up the auditory status of military personnel after an acute acoustic trauma and to identify the possible predictive value of hearing thresholds and otoacoustic emissions during the first 24 hours after the acoustic trauma. STUDY DESIGN: A group of 24 young military subjects, aged 22 +/- 2.3 years, without any otologic problem before the acoustic trauma, were examined at three time intervals after an accidental acoustic trauma caused by the discharge of a firearm: 24 hours, 72 hours, and 15 days. METHODS: Each subject was submitted to medical examination and to a questionnaire detailing the circumstances of the acoustic trauma. Pure tone audiometry was performed from 1 to 8 kHz per half octave. Transiently evoked otoacoustic emissions were recorded in the nonlinear mode at 80 dB pSPL, and distortion product otoacoustic emissions were recorded from 1 to 6 kHz, using a distortion product-gram type procedure, at 65/55 dB SPL, with f2/f1 = 1.22. Two groups of subjects were defined: group 1 (n = 8) represented subjects with short-lasting tinnitus (<72 h) and group 2 (n = 16) subjects with long-lasting tinnitus (>72 h). RESULTS: Hearing thresholds did not differ significantly between these two groups 24 hours after the acoustic trauma. However, otoacoustic emissions showed significantly lower amplitudes 24 hours after the acoustic trauma in subjects showing a longer lasting tinnitus. CONCLUSION: Otoacoustic emissions appear to be a better predictor of the persistence of tinnitus than hearing thresholds alone 24 hours after an acute acoustic trauma.     

单侧环杓关节损伤嗓音声学检测

目的 :探讨计算机声学检测在诊断及治疗单侧环杓关节损伤患者中的应用价值。方法 :采用计算机嗓音声学测试系统 (Dr .SpeechScienceforWindows)对 5 0例正常成人及 30例单侧环杓关节损伤患者持续元音[a]信号进行检测 ,对其主要声学参数及声谱图特征进行比较分析 ,观察杓状软骨拨动治疗后嗓音声学性质变化。结果 :单侧环杓关节损伤嗓音各项声学参数值均较正常值明显增高 ,差别有显著意义 ;声谱图表现中高频区谐波及共振峰损害 ,声能减弱或消失 ,噪声成分增加。固定声带的位置直接影响嗓音声学性质 ,NNE更能客观反映声带的位置及声门闭合程度。杓状软骨拨动后 33%痊愈者显示声学参数及声谱图恢复正常 ;47%好转者表现声学参数值下降 ,声谱图谐波及共振峰逐渐恢复 ,噪声减少 ;2 0 %无效者术后声学特征无明显改变。结论 :计算机声学分析各项参数均可作为评价环杓关节损伤嗓音损害程度的定量指标 ,NNE可作为客观反映声带位置及声门闭合程度的定量参数。声谱图和声学参数结合 ,有助于对环杓关节损伤疗效及预后的客观评价。     

Sensorineural high-frequency hearing loss after drill-generated acoustic trauma in tympanoplasty

Summary Tympanoplasty can cause a sensorineural hearing loss by a mechanism of acoustic trauma. Although this lesion appears to be relatively infrequent in clinical practice, we believe that its low apparent incidence is caused when clinicians fail to assess the auditory frequencies above 8000 Hz. Twenty-four patients with normal bone-conduction audiometric thresholds scheduled for tympanoplasty were assessed with an electro-stimulation, bone-conduction high-frequency audiometer which can measure hearing frequencies up to 20 kHz before and after surgery. A measurable hearing loss was found in the upper limits of the audible frequencies in 9 patients (37.5%), and was considered important in 4 of them (16.7%). This hearing loss was recorded above the upper frequency limit of conventional audiometers. The findings in this study indicate that drilling of the temporal bone can impair the hearing level in the high frequencies in a significant number of patients. High-frequency audiometry is a very sensitive tool to assess any damage caused to the inner ear by surgical procedures carried out in the middle ear and temporal bone.Presented at the First European Congress of Oto-Rhino-Laryngology and Cervico-Facial Surgery, Paris, 26–29 September 1988     

Selectivity for temporal characteristics of sound and interaural time difference of auditory midbrain neurons in the grassfrog: A system theoretical approach

The selectivity for temporal characteristics of sound and interaural time difference (ITD) was investigated in the torus semicircularis (TS) of the grassfrog. Stimuli were delivered by means of a closed sound system and consisted of binaurally presented Poisson distributed condensation clicks, and pseudo-random (RAN) or equidistant (EQU) click trains of which ITD was varied. With RAN and EQU trains, 86% of the TS units demonstrated a clear selectivity for ITD. Most commonly, these units had monotonically increasing ITD-rate functions. In general, units responding to Poisson clicks, responded also to RAN and EQU trains. One category of units which showed strong time-locking had comparable selectivities for ITD with both stimulus ensembles. A second category of units showed a combined selectivity for temporal structure and ITD. These units responded exclusively to EQU trains in a nonsynchronized way. From the responses obtained with the Poisson click ensemble so-called Poisson system kernels were determined, in analogy to the Wiener-Volterra functional expansion for nonlinear systems. The kernel analysis was performed up to second order. Contralateral (CL) first order kernels usually had positive or combinations of positive and negative regions, indicating that the contralateral ear exerted an excitatory or combined excitatory-inhibitory influence upon the neural response. Ipsilateral (IL), units were characterized by first order kernels which were not significantly different from zero, or kernels in which a single negative region was present. A large variety of CL second order kernels has been observed whereas rarely IL second order kernels were encountered. About 35% of the units possessed nonzero second order cross kernels, which indicates that CL and IL neural processes are interacting in a nonlinear way. Units demonstrating a pronounced selectivity for ITD, were generally characterized by positive CL combined with negative IL first order kernels. Findings suggested that, in the grassfrog, neural selectivity for ITD mainly is established by linear interaction of excitatory and inhibitory processes originating from the CL and IL ear, respectively. Units exhibiting strong time-locking to Poisson clicks and RAN and EQU trains had significantly shorter response latencies than moderately time-locking units. In the first category of units, a substantial higher number of nonzero first and second order kernels was observed. It was concluded that nonlinearr response properties, as observed in TS units, most likely have to be ascribed to nonlinear characteristics of neural components located in the auditory nervous system peripheral to the torus semicircularis.     

Noise-noise effect upon the spreading of the posttraumatic progressive necrosis in the organ of Corti

Summary Progressive necrosis of the organ of Corti caused by a disturbance of the ionic composition of the Cortilymph resulting from the infiltration of endolymph into the organ of Corti after traumatization of its barrier against the scala media, is greatly intensified by posttraumatic stimulation with noise of physiological intensities. This effect is attributed to oscillation of the cochlear partition, with resultant greater blending of the Cortilymph and the endolymph. Stimulation augments necrosis fourfold towards the base of the cochlea and twofold towards the helicotrema. Posttraumatic stimulation is one of the factors which markedly potentiate the regressive effect of acoustic trauma.     

Enhanced evoked response amplitudes in the inferior colliculus of the chinchilla following acoustic trauma

Evoked response amplitude-level functions were measured from electrodes in the inferior colliculus of the chinchilla before and after exposure to a 2 kHz pure tone of 105 dB SPL. The exposure produced approximately 20–30 dB of permanent threshold shift from 2 to 8 kHz, but little or no hearing loss at higher or lower frequencies. Generally less than 60% of the outer hair cells were missing in the region of hearing loss. The amplitude-level functions measured at 4 and 8 kHz generally showed a loss in sensitivity at low sound levels, a reduction in the maximum amplitude and sometimes steeper than normal slopes. The amplitude-level functions measured at 2 kHz also showed a loss in sensitivity; however, the maximum amplitude was often greater than normal. Even though there was no loss in sensitivity at 0.5 kHz, the amplitude-level function was steeper than normal and the maximum amplitude of the evoked response was almost always substantially larger than normal. The enhancement of the evoked response amplitude from the inferior colliculus does not appear to originate in the cochlea, but may reflect a reorganization of neural activity in the central auditory pathway.     

Regeneration of hair cell stereociliary bundles in the chick cochlea following severe acoustic trauma

Examination of pure-tone acoustic damage in the chick cochlea revealed a significant amount of hair cell recovery over a 10 day period following the exposure. The recovery included both a regeneration of stereociliary bundles to replace those that were lost and a reshuffling of the mosaic pattern of the hair cell surfaces that survived. Ten-day-old chicks were exposed to a 1500 Hz pure tone at 120 dB SPL for 48 h and their cochleae were processed for scanning, transmission and light microscopy at 0 h, 24 h. 48 h, 4 d, 6 d and 10 d after exposure. Immediately after exposure the damaged region exhibited two types of hair cell trauma. The first was a defined area of complete hair cell loss and the second was an area where the hair cells survived but exhibited varying amounts of stereocilia injury. After 48 h of recovery, new hair cells were identifiable in the region of hair cell loss and with time they underwent a progressive maturation of their stereociliary bundles. The surviving hair cells showed a dramatic rearrangement and expansion of their surfaces but exhibited no repair of the damaged stereociliary bundles. These results suggest that the chick cochlea is capable of a significant amount of recovery and regeneration following acoustic trauma.     

Steady state EP is not responsible for hearing loss in adult chickens following acoustic trauma

The steady state DC endocochlear potential (EP) in young chicks shows a large decrease after acoustic overstimulation followed by a rapid recovery that parallels the recovery of threshold (Poje et al., Hear. Res. 82 (1995) 197–204). These results raise a question as to whether or not the EP could account for the hearing loss and make a significant contribution to the recovery of the threshold. In contrast to results in young chicks, we show that acoustic overstimulation, which causes extensive hair cell damage, does not cause a decrease in the steady state EP in adult chickens. However, there is a significant reduction in the negative EP seen during anoxia which persists even after 4 weeks of recovery. Thus, our results indicate that the steady state EP cannot account for the hearing loss observed in adult chickens.