听力测定

定义

An audiometry exam tests your ability to hear sounds. Sounds vary, based on their loudness (intensity) and the speed of sound wave vibrations (tone).

Hearing occurs when sound waves stimulate the nerves of the inner ear. The sound then travels along nerve pathways to the brain.

Sound waves can travel to the inner ear through the ear canal, 耳膜, 中耳骨骼(空气传导). They can also pass through the bones around and behind the ear (bone conduction).

The INTENSITY of sound is measured in decibels (dB):

• 耳语大约是20分贝.
• Loud 音乐 (some concerts) is around 80 to 120 dB.
• 喷气发动机的分贝约为140至180分贝.

Sounds greater than 85 dB can cause 听力损失 after a few hours. Louder sounds can cause immediate pain, and 听力损失 can develop in a very short time.

The TONE of sound is measured in cycles per second (cps) or Hertz (Hz):

• 低音范围约50至60赫兹.
• Shrill, high-pitched tones range around 10,000 Hz or higher.

The normal range of human hearing is about 20 to 20,000 Hz. 有些动物可以听到高达50,000赫兹的声音. 人类的语音频率通常是500到3000赫兹.

选择的名字

听力测定; Hearing test; Audiography (audiogram)

如何执行测试

Your health care provider may test your hearing with simple tests that can be done in the office. These may include completing a questionnaire and listening to whispered voices, 音叉, 或来自耳朵检查范围的声音.

A specialized tuning fork test can help determine the type of 听力损失. The tuning fork is tapped and held in the air on each side of the head to test the ability to hear by air conduction. It is tapped and placed against the bone behind each ear (mastoid bone) to test bone conduction.

A formal hearing testing can give a more exact measure of hearing. 可以进行以下几种测试:

• Pure tone testing (audiogram) -- For this test, you wear earphones attached to the audiometer. Pure tones of a specific frequency and volume are delivered to one ear at a time. You are asked to signal when you hear a sound. The minimum volume required to hear each tone is graphed. A device called a bone oscillator is placed against the mastoid bone to test bone conduction.
• Speech audiometry -- This tests your ability to detect and repeat spoken words at different volumes heard through a head set.
• Immittance audiometry -- This test measures the function of the ear drum and the flow of sound through the middle ear. A probe is inserted into the ear and air is pumped through it to change the pressure within the ear as tones are produced. A microphone monitors how well sound is conducted within the ear under different pressures.
• Tympanometry -- A measure of the vibration of the ear drum and middle ear pressure.

如何准备考试

不需要特别的步骤.

考试的感觉如何

没有不适. 时间长短不一. An initial screening may take about 5 to 10 minutes. 详细的听力测量可能需要大约1小时.

为什么要进行测试

这个测试可以检测 听力损失 在早期阶段. It may also be used when you have hearing problems from any cause.

正常的结果

正常结果包括:

• The ability to hear a whisper, normal speech, and a ticking watch is normal.
• The ability to hear a tuning fork through air and bone is normal.
• 详细的听力测量, hearing is normal if you can hear tones from 250 to 8,25db或更低时，000hz.

异常结果意味着什么

There are many kinds and degrees of 听力损失. 在某些类型, you only lose the ability to hear high or low tones, 或者你只失去空气或骨传导. The inability to hear pure tones below 25 dB indicates some 听力损失.

The amount and type of 听力损失 may give clues to the cause, 还有恢复听力的机会.

The following conditions may affect test results:

• 听神经瘤
• Acoustic trauma from a very loud or intense blast sound
• 年龄相关性听力损失
• Alport综合征
• 慢性耳部感染
• 迷路炎
• 梅尼埃病(又名内耳眩晕
• 持续暴露在巨大的噪音中，如噪音 工作 或从 音乐
• Abnormal bone growth in the middle ear, called 耳硬化症
• 鼓膜破裂或穿孔

风险

没有风险.

注意事项

Other tests may be used to determine how well the inner ear and brain pathways are 工作ing. One of these is otoacoustic emission testing (OAE) that detects sounds given off by the inner ear when responding to sound. This test is often done as part of a newborn screening. A 头部核磁共振 may be done to help diagnose 听力损失 due to an acoustic neuroma.

参考文献

阿蒙森GA. 听力测定. 见:福勒GC编. Pfenninger and Fowler's Procedures for 初级护理. 第四版. Philadelphia, PA: Elsevier; 2020:chap 59.

Kileny PR, Zwolan TA, Slager HK. Diagnostic audiology and electrophysiologic assessment of hearing. In: Flint PW, Francis HW, Haughey BH, et al, eds. Cummings Otolaryngology: Head and Neck Surgery. 7日艾德. Philadelphia, PA: Elsevier; 2021:chap 134.

刘HL，田中C, Pogoda TK，霍尔JW. 听觉、前庭和视觉障碍. 见:Cifu DX编. 布拉多姆的物理医学 & 康复. 6日艾德. Philadelphia, PA: Elsevier; 2021:chap 50.