An Audiometry or hearing test is an evaluation of the sensitivity of a person’s sense of hearing. Audiometry is performed to test a person's ability to hear the sound frequencies necessary for speech. The test is carried out by a trained specialist called an audiologist with an instrument called an audiometer.
Our ear is divided into three parts. External ear, Middle ear and Inner ear. According to involvement of different parts of ear, deafness type & severity varies which can be confirmed by Audiometry.
There are three types of deafness / hearing loss.
Audiometry test is a basic test to identify and diagnose type and severity of hearing problems.
There is no need of any specific preparations.
The ears are routinely examined with an otoscope before audiometry testing to determine if there are any blockages in the ear canal. If excessive wax is present, the patient is sent to a doctor for removal of the wax. It should be cleaned before subjecting patient to audiometry.
A person with normal hearing should be able to recognize and respond to all of the tone frequencies and the different volumes used during the audiometry test in both ears. Normal speech is generally spoken in the range of 20-50 decibels.
According to severity of deafness, it is divided into :
The pattern of responses displayed on the audiogram are used by the audiologist to determine if a significant hearing loss has occurred and if the patient might benefit from further testing for differential diagnosis, hearing aids, or corrective surgery. The pattern of responses displayed on the audiogram are used by the audiologist to determine if a significant hearing loss has occurred and if the patient might benefit from further testing for differential diagnosis, hearing aids, or corrective surgery.
Any hearing problems found may be investigated by physicians and treated by physicians or speech-language pathologists, depending on the nature of the problem. An unexplained difference between the two ears in the tone test or the speech test may warrant another test, called an auditory brain stem response (ABR) to look for a possible acoustic tumor. Or, a difference in hearing between the two ears may be explained by case history information, such as noise exposure. If necesssary, imaging studies, such as a CT scan, will be ordered by physicians and performed by radiologic technologists.
Audiometry is a very safe & simple OPD procedure. Audiometry tests are carried out in a soundproof testing room equipped with audiometry equipment such as an audiometer, earphones, special headband, and a small listening booth for the audiologist. Audiometry equipment consists of devices emitting sounds or tones, like musical notes, at various frequencies, or pitches, and at various levels of loudness. The audiologist may need to decrease and increase the loudness of the tone a few times to establish the patient's hearing threshold. Patient is explained about the procedure and head phones is given. Sounds of different frequencies are emitted. Pt suppose to say whether he/she can hear or not. The test results are plotted by the audiologist, and they show hearing loss as a function of frequency. Such a plot is called an audiogram and it usually shows the low frequencies or tones at one end and the high frequencies at the other end. A typical audiogram also reports results for both the left and right ears, since it is not unusual for levels of sensitivity to sound to differ from one ear to the other. The audiogram also plots the volume of the tones used for the test: from soft, quiet sounds at the top of the plot to loud sounds at the bottom. Hearing is measured in decibels, the unit of a logarithmic scale of sound intensity.