While humanities hearing may be incredibly weak compared to some of our mammalian cousins it is still a very vital part of our world view. To lose your ability to hear would put you in a soundless world. Imagine not being able to understand what people are saying to you anymore or even not being able to hear your favorite song ever again? Most musicians would be absolutely devastated if they went deaf(though some like Beethoven would keep on marching forward). Aside from deafness there is even the chance of gradually losing your hearing. Imagine a person screaming at you at the top of their lungs and it only sounding like a whisper? This is a very real problem for some unfortunate people. Luckily we have tests for hearing loss today, and with their help we can prevent a lot of suffering from hearing loss. This article will cover history of a few hearing loss tests and how they work.
There are several different kinds of hearing loss. Three to be exact. These types of hearing loss are neural/sensorineural hearing loss, conductive hearing loss, or a combination of both forms of hearing loss. Conductive hearing loss is the result of sound not being conducted properly in the instruments of the outer ear, middle ear or both. This is usually a mild impairment but can range up to a fairly moderate impairment. Even with conductive hearing loss the inner ear can still receive sound waves so if the sound is loud enough it can generally still be heard. More severe forms of conductive hearing loss exist. This is called otosclerosis. Otosclerosis occurs because of abnormal bone growth near the ear that can cause canal obstruction as the result of hearing damage. Generally with conductive hearing loss the patient will still be able to make out general speech and other noises but may require a form of amplification such as a hearing aid.
The next kind of hearing loss is neural or sensorineural hearing loss. This is the result impaired function of the auditory nervous system. This can range from a very mild hearing problem to total deafness. This kind of hearing loss is usually due to the insensitivity of the cochlea or inner ear. There are many different problems with various parts of the inner ear or the various nerves of the eart. This can involve problems with the hair cells in the cochlea, problems with the cranial nerve, problems with the vestibulocochlear nerve, or portions of the brain that perceive audio. With this kind of hearing loss people may be able to hear but quality can be very poor.
The first hearing loss test is the Rinne test. This test compares the way sounds are percieved when they are transmitted either by air or bone conduction. This test is used to quickly tell if a person is suffering from conductive hearing loss but it is totally ineffective at detecting neural or senorineural hearing loss. For this reason the Rinne test should always be used in conjunction with the second test, the Weber test. The Rinne hearing loss test was named after a german otologist named Heinrich Adolf Rinne. The procedure of the Rinne test is very simple. The doctor places a tuning fork which usually vibrates at either 512 or 256hz on the mastoid of the patient. This tests their ability to recognize sound through conduction on the skull which tells them how well they can hear on the inner ear. Afterwards the same tuning fork is struck again and placed outside the ear of the patient to test if they can hear sound that is conducted through the air. This tests how well their outer and middle ear are working. This tests value has been heavily questioned, especially as an effective hearing screening test.
The Weber test is another test for hearing loss. It was primarily used as a screening test to be used quickly. The weber hearing loss test is designed to test one-sided conductive hearing loss and also one-sided sensorineural hearing loss. This test is named after Ernst Heinrich Weber, a German scientist.
The performance of this test is also highly questionable. The procedure of the Weber test is done by taking a tuning fork, same as in the Rinne test, and striking it and placing it in the middle of the patient's forehead. The patient is then asked in which ear the noise is heard louder. This test can quickly tell if a patient has hearing loss in one ear but not the other because a health person should hear the sound as the same volume in both ears. This test can also check if a patient has one-sided conductive hearing loss. If a patient has a conductive hearing problem in one ear they will hear the sound as much louder in the damaged ear rather than the healthy ear. This is because the inner ear in the ear with conductive damage will pick up the sound easily because the tuning fork is placed on the bone of the patient. However the healthy ear will mostly pick up the sound traveling through the air and will not perceive the sound to be nearly as loud. If you do not understand then you can easily test this by performing the test on yourself and plugging one ear.
The Bing test is similar to the Weber test. This hearing loss test was devised by another German otologist by the name of Albert Bing. This test is very much like the weber test except that it uses a low frequency tuning fork and is used to test for the Occlusion effect rather than unilateral hearing loss. The occlusion effect is an effect that occurs when the outer portion of a person's ear canal is covered with an object. The person will then hear a booming type sound similar to an echo when they hear their own voice. This allows a person to hear sounds they don't notice which normally escape right out of the ear drum.