应用后效和逆转掩蔽试验做听分析器定位诊断

后效(residual)掩蔽系指在一对声音中,由于头一个声音最强影响,第二个声音的阈值升高的现象。逆转掩蔽则是在后面的第二个声音较强声音影响下,前面的声音阈值升高现象。这两种掩蔽只在前后两个声音间隔在1～50ms时表现的最为明显,间隔延长则效果减弱。作者用做被掩蔽的声为2000Hz纯音,而掩蔽声为含有被掩蔽纯音频率的窄带噪声(1600～2500Hz)。为使掩蔽作用的大小统一,在不同受试者应用能引起相同响度的掩蔽声强。10     

弱噪声前掩蔽对下丘神经元频率调谐的影响

目的 探讨在加入弱噪声前掩蔽的条件下，下丘神经元对声信号的频率调谐（frequency—tuning）的改变。方法12只小鼠在自由声场条件下，选用相当于纯音听阈上5dB强度不同时程（40、60、80、100ms）的弱包络白噪声作为前掩蔽声，观察其对神经元频率调谐的影响。结果弱噪声前掩蔽使大部分神经元的频率调谐曲线（frequency tuning curve，FTC）锐化（P〈0．01），并有随掩蔽声时程的延长而锐化程度增加的趋势（P〈0．05）。通过计算FTC的反转斜率（inverse—slope，IS），发现弱噪声前掩蔽对高频边的抑制率明显高于低频边，大部分神经元的高频边反转斜率（IShigh）减小，且有随掩蔽声时程延长而减小程度增加的趋势（P〈0．01）；而低频边反转斜率（ISlow）的变化无规律。掩蔽声还使神经元对探测声的反应阈值升高（P〈0．0001，n=31），且随着掩蔽声时程的延长而升高幅度增大。结论弱噪声前掩蔽使神经元FTC发生锐化、阈值升高，此效应随掩蔽声时程的延长而加强。     

压耳式及插入式耳机给声诱发听性脑干反应

目的比较以压耳式及插入式耳机给声诱发的听性脑干反应(ABR)的差异。方法以TDH-39P压耳式和ER-3A插入式耳机给声,通过真耳测试短声在外耳道的频谱图,对一组听力正常青年人(男30耳,女24耳)进行短声诱发ABR测试,并观察对侧给予白噪声掩蔽后ABR反应阈的改变。结果两种给声方式诱发出极为相似的ABR波形,两者反应阈及潜伏期均无显著性差异(P>0.05)。采用插入式耳机对侧加40～70dBSPL强度的白噪声对ABR的阈值及阈上10dB强度下波V潜伏期均无显著性影响(P>0.05)。真耳分析测试结果显示两种耳机给声方式下外耳道短声的频谱图极为相似,仅强度相差3dB(0.5～4kHz)。结论插入式和压耳式耳机给声方式的ABR测试结果之间无显著性差异。为此,建议临床中应准备两种给声方式并获取相应的正常值,以便使用时灵活选择。插入式耳机对侧给声的ABR掩蔽不存在中枢掩蔽现象。     

听力正常人群噪声竞争条件下声源定位能力研究

目的 空间听觉对于感知周围环境至关重要。真实世界的听力经常涉及具有多个声源的嘈杂环境。本研究拟对听力正常受试者进行水平方位的声源识别测试,探索不同噪声条件对声音定位能力的影响,比较获得适用于嘈杂环境下声源定位测试的噪声条件。方法 本研究为横断面研究。一共纳入28名听力正常受试者,测试阵列由前方37个间隔5°的扬声器组成,刺激声信号为0.25,0.5,1,2,4,8 kHz啭音,强度为50 dB SPL。测试条件包括安静、白噪声35 dB SPL(WN35)、白噪声40 dB SPL(WN40)、言语噪声40 dB SPL(BN40)。采用均方根误差(Root-mean-square error, RMSE)为评估指标。结果 受试者安静条件下的声源定位能力明显优于噪声条件（安静-WN35:Z=3.461,P=0.001;安静-WN40:Z=4.440,P=0.000;安静-BN40:Z=3.803,P=0.000）。WN35条件下的结果明显优于WN40条件下的结果（Z=2.687,P=0.007）。WN40和BN40条件之间没有显着差异（Z=1.207,P=0.227）。在噪声条件下,受...     

正常气骨导听性脑干反应及其应用

［摘要］目的：研究骨导听性脑干反应(ABR)的波形特点及正常的气、骨导ABR Ⅴ波潜伏期-强度曲线及相应的反应阈值，为临床气导ABR（AC ABR）和骨导ABR(BC ABR)的联合应用提供参考依据。方法：利用Nicolet spirit型诱发电位仪、EAR 3A插入式耳机和Radioear B 71骨振动器对一组听力正常年轻人（男32耳、女24耳）进行短声气骨导ABR测试，并观察对侧给予白噪声掩蔽对BC ABR阈值及潜伏期的影响。结果：气骨导ABR相应强度下波形相似波Ⅴ潜伏期－强度曲线表明，随着刺激强度逐渐减低，潜伏期逐渐延长。骨导Click的潜伏期要比气导Click潜伏期延长的程度大，BC ABR反应阈比气导ABR高。对侧70?dBSPL以下强度宽带噪声的使用对BC ABR阈值及阈上10?dB强度下波Ⅴ潜伏期均无显著影响（P＞0.05）。结论：(1) BC ABR波形特点与相应刺激强度的AC ABR极为相似。BC ABR与AC ABR潜伏期-强度函数曲线可望联合用于传导障碍及其程度的评估；(2) 骨导行为的听阈水平超过40?dBHL时，BC ABR难以引出，对其结果的解释应持慎重态度；(3) 骨导ABR测试时常规加对侧噪声掩蔽，但掩蔽声强度不应超过60?dB。     

耳鸣的心理声学测试方法(1)

耳鸣是在无外界声刺激或其他刺激时产生的一种声音感觉,它是一种自觉症状、主观感觉,迄今尚缺乏一种行之有效的客观检测方法。本文主要介绍目前用于对耳鸣的音调、响度以及掩蔽效应等心理声学测试方法,以达到对耳鸣的基本性质(包括心理声学的特征)、分类及可能原因提供信息,帮助确定需要治疗的患者(尤其是选择适应于耳鸣掩蔽治疗     

不同刺激速率和掩蔽强度对听力正常婴幼儿骨导听性脑干反应的影响

目的观察不同的刺激速率以及对侧不同强度的白噪声掩蔽对婴幼儿骨导听性脑干反应(ABR)的影响。方法对18例(36耳)正常婴幼儿分别在27.7次/秒(无掩蔽、等值掩蔽、升值20 dB掩蔽、升值40 dB掩蔽)和55.1次/秒(无掩蔽)的刺激速率下行骨导ABR测试,对结果进行比较。结果 18例(36耳)受试婴幼儿气导ABR反应阈均值为15.29±9.71 dB nHL,在35 dB nHL及以下刺激强度下均可记录到清晰、稳定、分化良好、重复性好的骨导ABR波形,骨导ABR反应阈均值为7.93±5.04 dB nHL;骨导短声刺激速率从27.7次/秒增加到55.1次/秒时,ABR波Ⅴ潜伏期明显延长(P<0.01);刺激速率为27.7次/秒、对侧不同强度的白噪声掩蔽时,骨导ABR波Ⅴ潜伏期以及反应阈差异无统计学意义(P>0.05)。结论骨导ABR测试受骨导刺激强度及刺激速率等的影响,在听力正常婴幼儿不受对侧耳有无掩蔽的影响。     

刺激强度对听力正常青年人畸变产物耳声发射的影响

目的探讨刺激强度对畸变产物耳声发射幅值及检出率的影响。方法选择听力正常青年14人(26耳),男11耳,女15耳,检测DPOAE幅值,f2/f1=1.2,幅值高于本底噪声3dB SPL有效,按刺激强度分三个试验进行:组1L1=65dB SPL,L2=55dB SPL;组2L1=L2=60dB SPL;组3L1=L2=50dB SPL。对所测三组结果进行统计学处理。结果三组幅值存在显著性差异,组1幅值最强,组3检出率最低,分别与另两组相比有显著性差异(P<0.01)。结论测试畸变产物耳声发射时,选择L1=65dB SPL、L2=55dB SPL作为刺激强度更为合理。     

噪声和听力损失对频率辨别的影响

本文对正常听力者和听力损失者各4名,在安静时和50、60、70、80和90dB SPL泜频(300～500Hz)噪声条件下,分别测试其500、1000和2000Hz的频率辨差阈,测试声均在每个受试者的掩蔽阈值上至少10dB。结果发现:在这三个频率中,正常听力者和听力损失者的频率辨差功能基本上是平行的,显然表明掩蔽噪声对这两组受试者的作用方式是相同的。在安静时,正常听力者在500、1000和2000Hz的频率辨差阈分別为2.72、6.62和9.54dB,而听力损失者则比正常听力者的频率辨差阈大,在最易受损的频率范围内尤为明显。当掩蔽噪声     

内耳拟老化大鼠模型对噪声损伤易感性研究

目的:应用本研究小组建立的内耳拟老化模型,研究其对噪声损伤的敏感性,并探讨线粒体DNA缺失(mtDNA)在大鼠对噪声损伤易感的可能作用.方法:2月龄Wistar大鼠32只随机分为4组,A组每日皮下注射D-半乳糖150 mg/kg体重,持续8周;继而暴露于声强为110 dB SPL的噪声环境中,每日连续刺激4 h,持续2 d.B组每日皮下注射0.9%生理盐水150 mg/kg体重,持续8周,然后给予噪声暴露,噪声条件同A组.C组用药方法同A组,D组用药方法同B组,C组和D组均不予噪声暴露.造模后2周测试ABR反应阈改变,并测试各组大鼠膜迷路总超氧化物歧化酶活力(T-SOD)、丙二醛(MDA)水平,同时应用巢式PCR(nest PCR)方法检测大鼠膜迷路mtDNA 4834缺失突变,并对PCR 产物进行测序.结果:A组大鼠ABR反应阈改变[(66.250±6.409)dB SPL]较B组[(35.625±4.955)dB SPL]明显提高,差异有统计学意义(P<0.01).A组T-SOD显著下降,MDA水平明显提高,与B组差异有统计学意义(P<0.01).大鼠内耳组织mtDNA4834缺失突变率分别为:A组87.5%(7/8),B组12.5%(1/8),C组75.0%(6/8),D组0(0/8).结论:内耳拟老化模型大鼠对噪声性聋易感,大鼠内耳组织mtDNA缺失突变可增加模型大鼠对噪声性听力损伤的易感性.     

Sound source localization

Sound source localization is paramount for comfort of life, determining the position of a sound source in 3 dimensions: azimuth, height and distance. It is based on 3 types of cue: 2 binaural (interaural time difference and interaural level difference) and 1 monaural spectral cue (head-related transfer function). These are complementary and vary according to the acoustic characteristics of the incident sound. The objective of this report is to update the current state of knowledge on the physical basis of spatial sound localization.     

The Masking of Binaural Beats of a Pure Sound with a Differential Sound

This study concerns the masking of binaural beats between a pure tone, stimulating one ear, of f₀ + d frequency (d = 3 Hz) and the differential sound originated in the other ear by stimulation with the mixing of 2 pure tones of frequency f₁, f₂ (f₂ – f₁ = f₀). The masking sound is a third-octave filtered white noise, of nominal frequency f_n variable between 200 and 4000 Hz, and sound pressure also variable. For each f_n and for each constant value of f₀, f₁, f₂, the minimum sound pressure level of the narrow-band noises for masking the beat is measured as a function of the frequency f_n; the sound pressure level of the pure tones is maintained constant at 45 dB. The minimum sound pressure level of the narrow-band noises for masking the normal beats (a pure tone of 315 Hz at the left ear, of 318 Hz at the right ear) is also determined. The latter measurement gives, as expected, a very deep minimum at 315 Hz; from the other measurements it results some oscillations of experimental values, with a mean value generally decreasing as the nominal frequency of the masking noise is increased. This phenomenon is discussed.     

Sound therapy in sudden deafness

Introduction and goalsIdiopathic sudden sensorineural hearing loss is a hearing disorder of unknown cause. The spontaneous recovery rate ranges from 50 to 75% of the patients. Scientific experiments on animals support the present study in patients with sudden deafness treated with sounds.Patients and methodsDuring the period 2003-2009, patients with idiopathic sudden sensorineural hearing loss were administered steroids, piracetam and antioxidants, together with the addition of sounds by means of music and words.ResultsComparing the results of patients treated with medication (n = 65) and those treated with medication and sounds (n = 67), it was observed that patients treated with medication and sounds had higher recovery. Within the group of patients treated with medication and sounds, 25 (37%) experienced complete recovery, 28 (42%) good recovery, 11 (16%) slight recovery and 3 (5%) poor or no recovery.ConclusionThe patients who recovered more than half of their audition accounted for 54% in the group treated with medication and for 79% in the group of patients receiving medication and sounds. Auditory recuperation showed no alterations, at least up to 12 months after therapy.     

Sound localization measured by eye-tracking

Objective: To introduce a new method of measuring sound localization ability based on eye-tracking and to test this method by analysing the influence of mild induced conductive hearing loss on sound localization. Design: Sound signals were presented from different angles, and the participant's responses were measured using an eye-tracking device. For validation, a comparison of responses to visual stimuli was performed. To test the clinical application of this method, a mild conductive hearing loss was simulated, and the impact of this change on sound localization was measured. Study sample: Fifteen participants. Results: The system provided repeatable measurements, and there was a good correlation of sound and visual signals. A large number of trials could be completed fairly rapidly. Following the induced conductive hearing loss, a decline of 5.5° in the accuracy of sound localization in the horizontal plane was found towards the side of the non-impaired ear for frontal presentations. Conclusions: Quantifying sound localization by eye-tracking was found to be feasible, fast and accurate. A mild conductive hearing loss caused a slight degradation of sound localization accuracy within the 30° frontal sector, which is in good agreement with results found using methods requiring more extensive instrumentation.     

Sound code for cochlear implants

This is a review of how various commercially available cochlear prostheses encode speech and complex tones. Arguments in favor of temporal coding through relatively few channels are presented. Advantages of analogue over pulsatile stimuli are explained. Parameters responsible for perception of vowels, consonants, musical pitch and loudness are didactically analyzed. Active rehabilitation is considered an integral part of the coding effort.     

声源定位测试的研究现状

综述听觉系统声源定位的机制及声源定位测试的研究现状。目前,听觉系统对于声音在双耳间形成的特定信号来辨识方向性的机制已研究得较成熟,但听觉中枢如何整合双耳间信号特性来定位的机制尚不明白。研究表明,大部分听障患者在经过听力干预后的声源定位能力都有不同程度的提高,但是使用双侧人工耳蜗或结合使用人工耳蜗和助听器的患者的声源定位能力较单侧使用耳蜗的患者好。     

Sound localization cues of binaural hearing

The ability to localize sound sources in space is of considerable importance to the human safety- and survival-system. Consequently the current scientific interest in improving the safety-standard i. e. in air-traffic control has provided a new momentum for investigating spatial hearing. This review deals with the nature and the relative salience of the localization cues. Localization refers to judgements of the direction and distance of a sound source but here we will deal with direction only. We begin with a short introduction into the so-called Duplex theory which dates back to John William Strutt (later Lord Rayleigh). The idea is that sound localization is based on interaural time differences (ITD) at low frequencies and interaural level differences (ILD) at high frequencies. If the head remains stationary neither a given ITD nor an ILD can sufficiently define the position of a sound source in space. On such a theoretical basis cones of confusion which open outward from each ear can be predicted ambiguously projecting any source on the surface of such a cone onto an interaural axis. Our restricted ability at localizing sound sources in the vertical median plane is another example of possible ambiguity. At the end of the 19th century scientists already realized that occlusion of the pinnae cavities decreases localization competence. As a result of later achievements in physics and signal-theory it became more obvious that the pinnae may provide an additional cue for spatial hearing and that the outer ear together with the head and the upper torso form a sophisticated direction-dependent filter. The action of such a filter is mathematically described by the so-called Anatomical Transfer Function (ATF). The spectral patterning of the sound produced by the pinnae and the head is most effective when the source has spectral energy over a wide range and contains frequencies above 6 kHz, that is it contains wavelengths short enough to interact with the anatomical characteristics of the outer ears. Scientific findings further suggest that spectral patterns like peaks and notches may also be exploited monaurally, albeit an a priori-knowledge at the central-auditive level concerning the corresponding transfer functions and relevant real-world sounds is required. Binaural spectral cues are more likely to play a major role in localization. They are derived from another transfer function, the so-called Interaural Transfer Function (ITF), being the ratio of the ATFs at the two ears. The contributions of all these cues may sometimes not be enough to prevent the listener from opting for the wrong direction. But things can be eased by allowing head-movements: More than 60 years ago science reasoned that small head movements could provide the information necessary to resolve most of the ambiguities. Recent studies have proved that these findings have been accurate all along.     

Sound levels from personal cassette players

Techniques have been devised whereby the levels at which users of personal cassette players listen to tape-recorded sounds through lightweight headphones may be measured and expressed in terms of free-field equivalent continuous A-weighted sound pressure levels. Data have been obtained on over 60 users of such devices who variously listened, in laboratory and field conditions, to music and speech against quiet and noisy backgrounds. The results have been interpreted in terms of noise exposure. Comparison with damage risk criteria indicates that 5% of the sample are listening in such a manner that habitual use would constitute a damage risk to hearing.     

Sound localization with phase audiometry.

A 500 Hz pure tone is presented binaurally with earphones. The tone is adjusted to give a midline impression at confortable loudness level. An electronic variable time delay line unit and a generator for randomizing the shift of the phase lag of the signal to the right or to the left ear, respectively, are used. By shortening the time delay the threshold of the recognition of the phase difference is reached. At every test sequence the tone is first presented in the center of the head without delay and then with delay. The patient runs the test by indicating in which ear the tone is heard. The phase difference is thus gradually reduced from 500 musec down to a threshold value of about 48 musec equal on right and left ears in normal-hearing subjects. The results of phase audiometry on subjects with normal hearing and with different types of hearing losses are in good agreement with the results of sound localization tests in free field. Phase audiometry seems to be of especial value in diagnosing retrocochlear lesions.