Audiometry is to determine whether audition is normal or not, and the degree and nature of dysaudia. Audiometry is of vital importance for the diagnosis and treatment of otic diseases. The peaceful environment free from noises is advisable for audiometry. There are the following methods.
1. Phone test
The test is to determine the patient’s auditory acuity of phone so that the severity of hypoacusis can be determined. The examinee closes his eyes and assumes the lateral sitting position, with the examined ear facing the examiner while the external orifice of the other ear is stopped up with the finger. The examiner is 6 m away, whispering. If the examinee can hear the whisper 3 m away from the examiner, the audition of the examinee is expressed as 3/6. Use the same method to determine the hearing of the other ear.
2. Audiometer test
As a simple method, the test can estimate the degree of hypoacusis roughly. The examinee assumes the lateral sitting position peacefully, with the eyes closed. Then he stops up the external ear orifice of one ear tightly with the finger. The examiner stands behind the examinee, holds an audiometer and approaches the ear to be examined step by step from the place far away until the sound of the audiometer is heard. Repeat the test several times and record the distance where the sound of the audiometer is heard. If the normal ear can hear the sound 100 cm away while the examinee can hear it 60 cm away, the hearing of the examinee is expressed as 60/100. Use the same method to determine the hearing of the other ear.
3. Tuning fork test
The test is the main method to determine the nature of hyposcusis. The commonly-used tuning fork is one with the frequency of 256 times / sec, or 512 times / sec.
4. Audiometer test
This is a more accurate method with the application of instruments. It can not only determine the mature of hypoacusis, but also the severity of hypoacusis. The audiometer can produce a number of sounds with different frequencies, and can also control the intensity of sound. Every frequency of the normal hearing is zero decibel. As for the patient with conduction deafness, the loss of low-pitched sound in air conduction is more serious than that of high- pitched sound, while the bone conduction is normal; as for the patient with nerve deafness, the loss of high-pitched sound in air conduction is severer than that of low-pitched sound, while the loss in bone conduction is equal to the loss in air conduction, or the loss in bone conduction is more; as for mixed deafness, the loss of low-pitched sound is at the same level as that of high-pitched sound in air conduction, or the loss of high-pitched sound is more, while the loss in bone conduction is less than that of air conduction.