Noise-Induced Hearing Loss
Noise and hearing loss
When the ears are exposed to extremely loud noises, or to prolonged loud noises, inner ear structures can be damaged, leading to noise-induced hearing loss.
What constitutes a loud noise?
Noise is characterized by intensity measured in decibels, pitch measured in hertz (Hz, which means cycles per second), and duration. Normal conversation levels occur at about 60 decibels. Continual exposure to more than 85 decibels can be dangerous. Pitch is the frequency of sound vibrations per second. The lower the pitch (deeper sound), the fewer vibrations per second.
According to the American Academy of Otolaryngology-Head and Neck Surgery, noise is damaging if:
How does a loud noise cause hearing loss?
Loud noises can cause damage to the hair cells in the inner ear and to the hearing nerve, called sensorineural hearing loss or nerve deafness. (Sensorineural hearing loss also can be caused by infection, head injury, aging, certain medications, birth defects, tumors, problems with blood circulation or high blood pressure, and stroke.)
Damage can occur from a brief, intense noise such as an explosion, or from continuous loud noises such as noises in a loud work environment. Hearing loss from loud noises may be immediate or occur slowly over years of continuous exposure.
Immediate hearing loss is often accompanied by tinnitus, or ringing in the ears or head. Immediate hearing loss can occur in one or both ears and often involves severe damage to the inner ear structure.
Prolonged exposure to noise can actually change the structure of the hair cells in the inner ear, resulting in hearing loss. Tinnitus, which is the sound of ringing, roaring, buzzing, or clicking inside the head, often occurs with prolonged noise exposure damage, as well.
Hearing loss from noise can be permanent or temporary.
Noises that cause hearing loss
Hearing loss can occur after a one-time exposure to a loud noise or after repeated exposure to varying loud noises. Exposure to loud noises can occur at work, at home, or at play. Examples of noises that can cause hearing loss either immediately or over time include:
Other noisy machinery
Preventing noise-induced hearing loss
When you know you will be exposed to loud noises, either temporarily or over a longer period, using ear plugs or ear muffs can help prevent hearing loss. Ear plugs, which fit into the outer ear canal, and ear muffs, which fit over the entire outside of the ear, decrease the intensity of the sound that reaches the eardrum. Other preventive measures include:
Protect small children from loud noises.
Be aware of hazardous noises in your environment.
Know which noises are too loud and can cause damage.
Undergo a medical examination to measure hearing.
Which noises can affect hearing?
Level of safety
Type of noise
Danger: Permanent hearing loss may occur
Firecrackers; rock concert
Chain saw; snowmobiles
Warning: Gradual hearing loss may occur over time