One of the main causes of hearing loss is exposure to loud sounds. It can happen from occupational noise (factory, lawnmower), leisure activities (sports arena, firearms) music (bar, concert) or accidental exposure such as a fire cracker explosion close by the ear. Hearing damage can happen from a one time event such as a loud concert or cumulative over time in a loud work environment. Headphones and earphones pose a great risk of noise exposure because the sound is directed right into the ear.
When sound waves are transmitted through the middle ear cavity to the inner ear for processing, the loudness of the sound waves is represented by the intensity of the vibrations against the oval window leading to the inner ear (cochlea). The cochlea is a shell-shaped structure that has channels of fluid inside. The movement against the oval window initiates a movement of fluid back and forth over tiny hair cells (cilia) housed within, in a highly organized fashion. When the intensity is so great, the cilia get damaged. Normal movement is no longer possible so sounds need to be louder to generate a response resulting in a hearing loss. Damage to the inner ear structures can also result in tinnitus (noises heard in the absence of external sounds).
Preventing hearing loss from noise exposure is accomplished by using earplugs whenever possible and turning sound levels down. Once a hearing loss has occurred, continued exposure to excessively loud levels will further damage hearing. Regularly scheduled hearing tests are a good way to monitor hearing status.
