Why and in what cases does one need hearing protection?

Acquiring the correct hearing protection when needed is often neglected and is sometimes the reason why individuals find themselves struggling with hearing impairments. Many people in South Africa participate in leisure or work activities that expose them to excessive noise. This exposure to excessive noise can be very damaging to a person’s ears, and may in some cases even cause irreversible damage. This is even truer for those who have a pre-existing hearing problem.

Even exposure to noises one may not think are damaging to the ears can cause problems. For example, if a person is often exposed to the sound of constant, heavy traffic (equalling on average 85 decibels), the chances are good that it will (with time) permanently damage their inner ear hair cells. The same can be said for persons who work with loud machinery on a daily basis.

Exposure to loud music is even more damaging to the ear, as it may reach up to 140 decibels (120 dB is the pain threshold)! This is a common problem, mainly due to the fact that many people listen to loud music in their leisure time, either through their earphones/headphones, speakers or at a concert.

Last, but not least, exposure to sudden, loud bursts of noise (such as a gunshot or explosion) causes the greatest damage to the ear since these noises often reach or exceed 150 decibels. In these cases, the damage to the ear can be instantaneous and permanent.

After an otoscopic examination has been completed, a tympanometer is used to measure the pressure and volume of the outer and middle ear. Tympanometry enables us to reliably test the function of the outer and middle ear. We also measure acoustic reflexes and according to these we have an indication of how well the middle ear muscles react to loud stimuli. When the Otoscopy and the tympanometry are completed and the results come back clear, the patient is ready for his or her hearing test to begin.

These tests are conducted in a device called a sound booth, and the standard and most common sound booth test, is known as the pure tone audiometry test. This test measures a patient’s air and bone conduction thresholds by playing pure tones to the patient through earphones that are connected to an exterior audiometer. Up to 16 different frequency bands are tested (depending on results), ranging between 250hz to 8000hz are used to test a patient’s hearing sensitivity.

After the pure tone audiometry tests are conducted, two different speech tests are conducted. These consist of Speech Reception Threshold testing and Speech Recognition Testing. These tests give audiologists an indication of how well a person would perform using speech, which is ultimately the signal that we listen to.

Another test that may or may not be conducted according to the case history or the test battery, would be a speech in noise test. This test is also conducted in a soundproof booth with an audiometer, and this test indicates how well a person performs in a noisy environment and can give us guidance on the treatment route that we need to undertake.