Every day, we experience sound in our environment, such as the sounds from television and radio, household appliances, and traffic. Normally, these sounds are at safe levels that don’t damage our hearing. But sounds can be harmful when they are too loud, even for a brief time, or when they are both loud and long-lasting. These sounds can damage sensitive structures in the inner ear and cause noise-induced hearing loss (NIHL).
NIHL can be caused by a one-time exposure to an intense “impulse” sound, such as an explosion, or by continuous exposure to loud sounds over an extended period of time.
When exposed to loud noise over a long period of time, a person may slowly start to lose their hearing. Because the damage from noise exposure is usually gradual, this might not be noticable, or the signs of hearing loss are ignored the until they become more pronounced. Over time, sounds may become distorted or muffled, and it might difficult to understand other people when they talk or have to turn up the volume on the television. The damage from NIHL, combined with aging, can lead to hearing loss severe enough that hearing aids could be needed to magnify the sounds around to help them hear, communicate, and participate more fully in daily activities.
NIHL can also be caused by extremely loud bursts of sound, such as gunshots or explosions, which can rupture the eardrum or damage the bones in the middle ear. This kind of NIHL can be immediate and permanent.
Loud noise exposure can also cause tinnitus—a ringing, buzzing, or roaring in the ears or head. Tinnitus may subside over time, but can sometimes continue constantly or occasionally throughout a person’s life. Hearing loss and tinnitus can occur in one or both ears. Sometimes exposure to impulse or continuous loud noise causes a temporary hearing loss that disappears 16 to 48 hours later, although researched show there may be residual long-term damage to the hearing function.
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National Institute of Deafness and Other Communication Disorders. Noise-Induced Hearing Loss. 2017
Metideiri M, Torres S. Noise-Induced Hearing Loss (NIHL): literature review. 2013