Causes of Hearing Loss
Hearing loss happens for many reasons. Some people lose their hearing slowly as they age. This condition is called presbycusis. Doctors do not know why presbycusis happens, but it seems to run in families.
Another cause is the ear infection otitis media, which can lead to long-term hearing loss if it is not treated.
Hearing loss can also result from taking certain medications. "Ototoxic" medicines damage the inner ear, sometimes permanently. Some antibiotics are ototoxic. Check with your doctor if you notice a problem while taking a medication.
Heredity also is a cause of hearing loss, but not all inherited forms of hearing loss take place at birth. Some forms can show up later in life. In otosclerosis, which is thought to be a hereditary disease, an abnormal growth of bone prevents structures within the ear from working properly. A severe blow to the head also can cause hearing loss.
One of the most common causes of hearing loss is loud noise. Loud noise can permanently damage the inner ear. Loud noise also contributes to tinnitus, which is a ringing, buzzing, or roaring sound in the ears.
Already, 26 million American adults between 20 and 69 years of age have permanently damaged their hearing due to exposure to loud noise at work or in leisure activities.
When we are exposed to harmful noise — sounds that are too loud or loud sounds that last a long time — sensitive structures in our inner ear can be damaged, causing noise-induced hearing loss (NIHL). These sensitive structures, called hair cells, are small sensory cells in the inner ear that convert sound energy into electrical signals that travel to the brain. Once damaged, our hair cells cannot grow back.
Scientists believe that, depending upon the type of noise, the pure force of vibrations from loud sounds can cause hearing loss. Recent studies also show that exposure to harmful noise levels triggers the formation of molecules inside the ear that contribute to hair cell damage and NIHL.
When a person is exposed to loud noise over a long period of time, symptoms of NIHL will increase gradually. Over time, the sounds a person hears may become distorted or muffled, and it may be difficult for the person to understand speech. Someone with NIHL may not even be aware of the loss, but it can be detected with a hearing test.