We hear sounds everyday, sounds like those of traffic, television, radio and other surroundings. Usually we hear these sounds at very controlled volumes so that it’s comfortable for our ears to receive it. But when the sound is too loud or a loud sound is played for too long, sensitive parts of our ear are exposed to these sounds, which damages them, thus causing Noise-induced Hearing Loss (NIHL), one of the more common types of hearing loss found in the modern world.
These harmful sounds, which are called noises, harm hair cells present in our ears. Hair cells are responsible for converting sound energy to electrical energy, which is then sent to the brain. These hair cells are very sensitive and once damaged cannot grow back again.
The cause can be exposure to either a very impulsive loud sound such as an explosion, which has a hard-hitting effect, or continuous exposure to loud sounds over a period of time, such as noise generated in mining and woodworking areas. To understand the nature of the sounds, which cause NIHL, we need to understand the nature of sound. Sound is measured in decibels. The noise from a fridge is 45 decibels, an average conversation is 60 decibels and heavy traffic noise can go up-to 90 decibels. According to a study, sound of more than 75 decibels can cause NIHL. Sounds such as that of a lawnmower, motorcycles or hedge cutter/ strimmer, which come in the range of 120-150 decibels, are known to cause NIHL. Sound’s which are less than 75 decibels, even after a long exposure do not hold a threat.
Exposure to such sounds not only causes damage to the hair cells but also damages auditory organs of the ear. The subtlest effect of NIHL is the occurrence of tinnitus-a ringing, buzzing or roaring in the ears- which might become severe with time. And this may occur in one or both ears together.
Another side effect of NIHL is temporary occurrence of hearing loss. If a person regains hearing after a certain time, it is called the temporary threshold shift, which in most cases disappears within 12-38 hours of occurrence.
The symptoms are not very clear and one has to observe with time as they increase gradually. With time the person starts hearing distorted and muffled sounds and might find it hard to interpret speech. In some cases the affected might not even realise. The best method is to conduct a hearing test.
As this is a hearing loss disorder there is no specific age of the affected people. Sports and recreational activities such as shooting, hunting, woodworking or other activities such as standing too close to speakers in a concert or performing in a live band might also cause Noise induced hearing loss.
NIHL’s prevention and cure are sorely dependent upon how careful an individual is. People should have good hearing habits in their everyday life so as to have a healthy life. Some of the precautions that can be taken are:
- One should know which noises cause it
- One should be alert to such noises
- One should wear earplugs and other safety equipment while visiting areas with higher noise exposure risks
- Spread the awareness, inform others