Hearing Loss

听力损失

Hearing loss is typically described as being conductive, sensorineural, or mixed.

听力损失通常被描述为传导性、感音神经性或混合型。

Conductive hearing loss refers to an impairment of one's ability to conduct airborne sound through the middle ear to the inner ear. Scar tissue or otosclerosis, the abnormal growth of bone within the middle ear, can lead to restricted movement of the ossicles. Recently it has been shown that there can also be conductive problems with the basilar membrane of the inner ear that reduce the efficiency of energy transfer to the hair cells (Holt).

Sensorineural hearing loss refers to impairment of the sensory unit consisting of the auditory nerve and the hair cells that excite it.

感音神经性听力损失是指由听神经和激发它的毛细胞组成的感受单元的功能障碍。

Sometimes the distinction between these two types of hearing loss can be made with a simple tuning fork test. If the tuning fork cannot be heard when sounded in air, then the base of the tuning fork is placed against the hard bone behind the ear. If the person can now hear it by conduction through the bone, then conductive hearing loss is indicated. It in cannot be heard by either air or bone conduction, then sensorineural loss is indicated.

有时可以通过简单的调谐叉测试来区分这两种听力损失类型。如果在空气中敲响调谐叉时无法听到，那么将调谐叉的底部放在耳后硬骨上。如果此时通过骨传导能听到，则表明存在传导性听力损失。如果通过空气传导或骨传导都无法听到，则表明存在感音神经性听力损失。

Hearing Loss 听力损失
0 to -15 dB 0 到 -15 分贝	Normal range 正常范围
-16 to -25 dB -16 至 -25 dB	Minimal loss 最小损失
-26 to -40 dB -26 至 -40 分贝	Mild loss 轻微损失
-41 to -55 dB -41 至 -55 分贝	Moderate loss 中等损失
-56 to -70 dB -56 至 -70 分贝	Moderate/severe loss 中度/重度损失
-71 to -90 dB -71 至 -90 分贝	Severe loss 严重损耗
> -91 dB -91 dB	Profound loss 深部损失

American Speech and Hearing Association

美国语音和听力协会

The "power of ten" or logarithmic nature of hearing response is evident in the fact that a loss in sensitivity by a factor of 10,000, or -40 decibels, is still at the edge of "minimal loss". By the admittedly simplistic "rule of thumb" for loudness, this -40dB sound would still be 1/16 as loud as the 0 dB reference. 0 dB in this table represents the normal hearing threshold, or 0 dB Hearing Level. The categories of hearing loss are based on measurements at 500, 1000 and 2000 Hz.

“十的幂”或对数性质的听觉响应在事实中显现出来，即灵敏度降低10000倍，或-40分贝，仍处于“最小损失”的边缘。根据 admittedly 简单的“响度规则”，这个-40dB的声音仍比0dB参考声低1/16。表中0dB代表正常听阈，或0dB听力级。听力损失的类别是基于500Hz、1000Hz和2000Hz处的测量结果。

Assessment of hearing loss

听力损失评估

Hearing Aids

助听器

传导性听力损失是指个体将空气传导声波通过中耳传导至内耳的能力受损。耳膜或耳硬化症（中耳内骨异常生长）可能导致听小骨运动受限。最近研究表明，内耳的基底膜也可能出现传导问题，从而降低能量传递到毛细胞的效率（Holt）。

Index

Hearing concepts

Dangers of Loud Sounds

Reference
Holt

ASHA

索引听力概念响声的危险参考 Holt ASHA

HyperPhysics***** Sound

HyperPhysics ***** 声音

R Nave

Go Back

Hearing Aids

助听器

Sometimes a satisfactory level of hearing can be restored by a hearing aid - a combination of a microphone to sense ambient sound, an amplifier, and a tiny speaker that projects the amplified sound into the ear canal. A typical modern hearing aid would employ an electret condenser microphone - small and rugged with a high signal-to-noise ratio. The frequency range of application is typically 100-10,000 Hz. While some assistance may be rendered by bone conduction, this discussion will be limited to hearing aids that operate by sounds produced in the air.

有时，通过助听器可以恢复满意的听力——这是一款结合了麦克风以感知环境声音、放大器以及一个微型扬声器，将放大后的声音投射入耳道的设备。典型的现代助听器会使用驻极体电容式麦克风——这种麦克风小巧且坚固，具有较高的信噪比。其应用频率范围通常为100-10,000 Hz。虽然有些帮助可能通过骨传导实现，但本讨论将限于通过空气传播声音的助听器。

Wearing Styles 穿着风格
ITE	In-the-ear 在耳内
BTE	Behind-the-ear 耳后
ITC	In-the-canal 在通道中
CIC	Completely in-the-canal 完全在耳道内
Body 物体	Worn on body (profound loss) 身体上的伤痕（深刻丧失）

A basic hearing aid may be called a linear circuit aid, implying that it simply amplifies any ambient sound that reaches it. It is important for such a hearing aid to contour the amplification to the nature of the hearing loss of the individual, which typically means amplifying high frequencies more than low frequencies. Presbycusis, the progressive loss of high frequency hearing with age, often calls for amplification of high frequencies with little or no bass boost. A basic hearing aid may have three frequency bands to permit the amplification to be adjusted based on the audiogram.

基本的助听器可能被称为线性电路助听器，这意味着它只是放大到达它的任何环境声音。对于这类助听器来说，重要的是根据个体的听力损失特性来调整放大效果，通常意味着对高频进行更多的放大，而对低频放大较少。老年性耳聋，即随着年龄增长高频听力的逐渐丧失，通常需要对高频进行放大，而低频几乎没有增强。基本的助听器可能有三个频率带，以便根据听力图调整放大效果。

The next step up in sophistication of the hearing aid would be to employ some kind of audio "compression". Compression implies the adjustment of the "gain" or degree of amplification based on the input level, it being a practical fact that louder sounds wouldn't need as much amplification. This compression would reduce the amplification for loud sounds either at the microphone end or at the speaker end. Some types of compression are called "adaptive compression" in that some logic is used to compress some kinds of sounds more than others.

在助听器的复杂性方面，下一步的提升可能是采用某种类型的音频“压缩”。压缩意味着根据输入电平调整“增益”或放大程度，因为事实是较响的声音不需要那么多的放大。这种压缩会在麦克风端或扬声器端对响声进行放大减弱。某些类型的压缩被称为“自适应压缩”，因为会使用一些逻辑来对某些声音进行更大幅度的压缩。

For those hearing aids that use adaptive compression, but not digital logic, some are classified under the headings ASP and K-AMP circuits. The ASP units monitor incoming sounds and automatically change the gain, output and frequency response. The K-AMP approach detects and amplifies only quiet sounds while leaving louder ones unaltered.

对于使用自适应压缩但不采用数字逻辑的助听器，一些被归类为ASp和K-AMP电路。ASp单元监测输入的声响，并自动调整增益、输出和频率响应。K-AMP方法仅检测并放大安静的声音，而让较大的声音保持不变。

Currently under very active development are the digital programmable hearing aids that use a digital signal processor (dsp). They can be programmed to more nearly fit the detailed needs of an individual user and open the door to more sophisticated approaches to assisting the user. Since the understanding of human speech is often the highest priority, and since speech has identifiable characteristics like vocal formants, some steps can be made to program the hearing aid to amplify speech sounds more than some distinctly different other types of sounds. A friend with a digital hearing aid told me something like "I leaned over an expressway bridge and listened to the traffic noise. After a short time there was a kind of burbling sound like the hearing aid was trying to make voices out of this sound." An intriguing idea, that we might get enough sophistication into hearing aids to recognize and selectively amplify the sounds of meaningful human communication.

目前正处于积极开发阶段的数字可编程助听器使用数字信号处理器（DSP）。它们可以被编程以更接近地满足个体用户的具体需求，并为更复杂的辅助方法打开大门。由于对人类语音的理解往往是最高的优先事项，而语音具有可识别的特征，如共振峰，因此可以采取一些步骤，将助听器编程以比一些明显不同的其他类型声音放大语音声音。一位拥有数字助听器的朋友告诉我类似的话：“我靠在高速公路桥上听交通噪声。过了一会儿，有一种像助听器试图将这种声音转化为声音的咕噜声。” 这是一个引人入胜的想法，即我们可能能够将助听器的复杂性提升到能够识别并选择性放大有意义的人类交流声音的程度。

Another approach to hearing assistance is the cochlear implant. Currently very expensive and in the experimental stage, it is one of the future possibilities.

另一种助听方法是耳蜗植入物。目前价格非常昂贵，仍处于试验阶段，是未来的一种可能性。

(Tal Berkowitz is acknowledged for investigative work on this topic.)

（Tal Berkowitz 因对本主题的调查研究工作而受到认可。）