Approximately 36 million Americans have hearing loss. One in three developed their hearing loss because of exposure to noise and loud sounds. Noise-induced hearing loss is caused by damage to the delicate hair cells of your inner ear. Once the hair cells are destroyed by exposure to harmful sounds, they cannot grow back, resulting in permanent hearing loss. Check out the NIDCD for detailed information regarding the mechanisms of noise-induced hearing loss.
NIHL (Noise-Induced Hearing Loss) can be caused by a one-time exposure to loud sound as well as by repeated exposure to sounds at various loudness levels over an extended period of time.
Sound is measured in units called decibels. Decibel levels begin at zero, which is near total silence and the weakest sound our ears can hear. By comparison, a whisper is 30 decibels and a normal conversation is 60 decibels. An increase of 10 means that a sound is 10 times more intense, or powerful. To your ears, it sounds twice as loud. The sound of an ambulance siren at 120 decibels is about 1 trillion times more intense than the weakest sound our ears can hear. Sounds that reach 120 decibels are painful to our ears at close distances.
Scientists believe that, depending upon the type of sound, the pure force of its vibrations at high decibel levels can cause hearing loss. Recent studies also show that exposure to sounds at harmful decibel levels triggers the formation of molecules inside the ear that damage hair cells. These destructive molecules play an important role in hearing loss in children and adults who listen to loud noise for too long.
Harmful sounds may be present at work, at home, or during leisure activities. Two types of sounds are primarily responsible for noise induced hearing loss: 1) very loud sounds that are sudden or impulsive (e.g., fireworks) and 2) moderately-loud sounds of longer duration (e.g., music over an extended period of time). A sound is dangerous if:
- It is painful or causes “ringing” in your ears.
- You have to should over the sound or noise in order to be heard.
- It causes a temporary decrease in hearing.
Can NIHL be prevented?
NIHL is 100 percent preventable. All individuals should understand the hazards of noise and how to practice good hearing health in everyday life. To protect your hearing:
- Know which noises can cause damage (those at or above 85 decibels).
- Wear earplugs or other hearing protective devices when involved in a loud activity (special earplugs and earmuffs are available at hardware and sporting goods stores).
- Be alert to hazardous noise in the environment.
- Protect the ears of children who are too young to protect their own.
- Make family, friends, and colleagues aware of the hazards of noise.
- If you suspect hearing loss, have a medical examination by an otolaryngologist (a physician who specializes in diseases of the ears, nose, throat, head, and neck) and a hearing test by an audiologist (a health professional trained to measure and help individuals deal with hearing loss.