Pathological auditory adaptation

Introduction Hearing adaptation, short exposure time under strong noise, hearing threshold increased by more than 10dB, and can be recovered after leaving the noise environment for a few minutes. Auditory adaptation is a phenomenon in which sustained sound stimulation causes a decrease in auditory susceptibility. The auditory system generally decreases in a first 1-2 minutes for a stable sound source, and then stabilizes at a level very quickly. The characteristic of auditory adaptation is that it is a balancing process. The study of auditory adaptation is the loudness balance method. That is, pure sound with a certain sound intensity (such as 80 decibels) acts on the left ear, and another sound with the same frequency but variable sound level acts on the right ear at the same time, so that both sounds equal. Then, stop the sound of the right ear and let the left ear continue to listen for 3 minutes. After this adaptation period, the left and right ears are re-equaled, and the equal-order level of the right ear is often lowered, for example, to 60 decibels, and the adaptation amount is 20 decibels.

Cause

Auditory adaptation is a phenomenon in which auditory stimuli are caused by auditory sensation caused by auditory organs for a long time.

an examination

Related inspection

Otolaryngology CT examination of newborn hearing screening

When this phenomenon occurs, it generally appears as a decrease in the stimuli and the sound sensitivity close to its frequency, but this reduction is generally temporary, and the sensitivity of the auditory organ is restored after a short period of time after the stimuli are stopped. normal. Studies have shown that when the sound only acts on one side of the auditory organ, hearing adaptation can occur in both ears. This shows that the mechanism of listening and adaptation is central. If the auditory organ is subjected to a long-term effect of strong auditory stimulation, the resulting decrease in auditory susceptibility often takes a day or night to recover.

Differential diagnosis

Need to be identified with the following symptoms:

Hearing fatigue: When you walk into a strong noise environment, you will feel uncomfortable. After stopping for a while, you will feel the hearing become dull. The slightest sound you can hear will not be heard. This is because your hearing threshold is up. , which causes your hearing to drop. However, as long as you leave the noise environment and rest for a period of time, the human hearing will gradually return to its original state. This phenomenon is called temporary hearing deviation, also known as hearing fatigue. It is only a temporary physiological phenomenon, and the hearing organs are not damaged. If working under strong noise for many years, the inner auditory organs are often stimulated by strong noise, and this auditory fatigue will be fixed and will not return to normal, resulting in permanent hearing loss or hearing threshold shift. This phenomenon is called noise deafness.

Hearing sensation: Hearing sensation, that is, the tympanic membrane muscle that maintains the tympanic membrane tension is dominated by the pterygoid nerve of the trigeminal nerve branch. The sacral muscle is dominated by the facial nerve, and the two muscles maintain an equilibrium relationship. When the facial nerve is paralyzed, the iliac muscle is paralyzed. Therefore, the tympanic membrane is relatively tense, the tympanic membrane tension is high, and the tiny sound produces strong vibration, which causes hypersensitivity. It is seen in the lesion of the facial nerve above the branch of the sacral muscle.

Hearing impairment: Hearing impairment refers to a structural defect of the auditory organ due to congenital or acquired causes, or a partial or total malfunction of the function, resulting in difficulty in listening or recognizing the sound; the criteria for identification are as follows:

(1) After receiving a self-conscious pure tone hearing test, the hearing frequency of the good ear is more than 25 decibels.

(2) Those who are unable to accept the previous paragraph's self-conscious pure tone hearing test, who are determined by his or her perceptual hearing test.

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