How can sound produce hearing loss

These bones are called the hammer or malleus , anvil or incus , and stirrup or stapes. They help sound move along on its journey into the inner ear. The vibrations then travel to the cochlea, part of the inner ear. The cochlea looks like a tiny snail shell. It is filled with liquid and lined with tiny hairs. The sound vibrations make the tiny hairs move.

There are two types of hair cells: the outer and inner cells. The outer hair cells take the sound information, make it louder and tune it. The inner hair cells change the sound waves into electrical signals. The hearing nerve then sends the signals to the brain, letting you hear.

There are many reasons why a person may not be able to hear. Hearing loss can run in some families, or a baby may be born with a problem with how the ear formed. Other causes of hearing loss include:. Ear infections and fluid behind the eardrum can cause hearing loss. When the infection goes away, hearing gets better. Doctors can do hearing tests at regular checkups or any time there is a concern that a kid does not hear well.

The doctor will send a baby or child with hearing loss to an audiologist. An audiologist say: ah-dee-AHL-uh-jist is someone who does hearing tests and helps people with hearing loss. The audiologist checks hearing by doing different types of tests. They even have hearing tests for babies! Maybe you've already had a hearing test?

You probably wore headphones and had to raise your left or right hand to show that you could hear in each ear. The kind of treatment depends on the type of hearing loss, what caused it, and how bad it is. In fact, our brains are capable of storing the neural equivalents of acoustic patterns like music, voices, danger sounds, and environmental sounds.

This similarity makes it much easier for us to recognize and process both familiar and unfamiliar sounds. Hearing loss occurs when sounds that are typically loud become softer and less intelligible; this is a result of our brain being misled through a loss of audibility. Information also becomes distorted as it reaches the brain, disrupting the quality of our hearing. Head trauma, neurologic disease, medical disorder or the process of simply aging, can result in alterations in the ability of the brain to process stimuli effectively.

This can lead to symptoms that reflect hearing loss; such symptoms may include inattention, inappropriate responses, and confusion. Our brain works with our ears in an incredible way, processing neural events into our hearing and all that it involves. A recent study found evidence of high-frequency hearing loss in nearly one third of a cohort of college students. To be perceived, sounds must exert a shearing force on the stereocilia of the hair cells lining the basilar membrane of the cochlea.

When excessive, this force can lead to cellular metabolic overload, cell damage and cell death. Concurrent exposure to ototoxic substances, such as solvents and heavy metals, may increase the damage potential of noise. Individual susceptibility to noise-induced hearing loss varies greatly, but the reason that some persons are more resistant to it while others are more susceptible is not well understood.

Recent animal experiments suggest that free oxygen radicals may mediate noise damage to hair cells. A teenaged girl was seen for a school physical examination. Screening audiometry performed in the office revealed a dB mild elevation of hearing thresholds at 4, Hz.

In response to questioning, the girl reported spending several hours a day listening to music through head-phones. The previous night, she had spent several hours at a rock concert without wearing hearing protection.

Audiogram findings in the patient in illustrative case 1. The area below the curves represents sound levels that the patient could still hear. Although complete recovery from a given episode can occur, repeated episodes of such shifts occurring after noise exposures give way to permanent threshold shifts because hair cells in the cochlea are progressively lost.

A year-old factory worker consulted his family physician because of ringing in his ears and depression that began soon after the onset of the tinnitus. He had seldom worn hearing protection at work, where he had to shout to communicate with co-workers. Away from work, he had difficulty understanding conversations in crowded rooms, and he said he often argued with his wife about the volume of the television set. His physical findings were normal.

An office audiogram showed a high-frequency hearing loss Figure 2. The patient was referred to an audiologist, who confirmed a sensorineural hearing loss that was probably caused by excessive noise exposure, with superimposed age-related changes.

A hearing aid was prescribed. Audiogram findings in the patient in illustrative case 2. This case shows that noise-induced hearing loss can interfere with speech discrimination and social functioning. Tinnitus is a common symptom of noise overexposure, and it further interferes with hearing acuity, sleep and concentration. These impairments have been associated with social isolation, depression and an increased risk of accidents.

Although no studies have evaluated the efficacy of educating patients about noise-induced hearing loss, family physicians can easily screen for excessive noise exposure during health maintenance visits Table 2.

Adolescents and their parents should be counseled about exposure to amplified music. Adults should be asked about firearms, noisy hobbies and noise exposure at work. Noise-induced hearing loss is permanent and only partially treatable, yet virtually percent preventable. Excessive noise should be avoided when possible. Hearing protection should be used correctly and consistently during exposure to excessive noise. Patients should be made aware of the availability of hearing protection and ways to use it correctly.

Do you need to turn up the television volume? Do you ask people to repeat sentences? Encourage patient to seek treatment. Advise patient to use hearing protection and avoid excessive noise lifelong to limit further hearing loss. A patient who reports significant exposure to noise should be informed that noise-induced hearing loss, although permanent and not fully treatable, is virtually percent preventable. The clinician can motivate patients to maintain their hearing health and thereby reduce the risk of hearing disability as they grow older Tables 2 and 3.

Key factors in this effort are learning to avoid excessive noise when possible and correctly using hearing protection when necessary. Hearing protectors, including earmuffs, disposable earplugs and custom-fitted earplugs, can provide 20 to 40 dB of attenuation when used correctly. Physicians can obtain samples from manufacturers and keep them in the office for distribution and demonstration of techniques for proper use.

Counseling about hearing protection is effective, although there is no evidence in favor of physician counseling. The Council for Accreditation in Occupational Hearing Conservation conducts courses in audiometry and hearing conservation for audiologists, audiometric technicians and medical professionals. Council for Accreditation in Occupational Hearing Conservation.

Wells St. Telephone: The National Hearing Conservation Association is a membership organization of professionals engaged in hearing conservation; the group also produces educational materials. National Hearing Conservation Association. Kenyon Ave. The League for the Hard of Hearing produces educational materials and programs about the noise hazards of toys and other common noise sources.

League for the Hard of Hearing. Telephone: voice or TTY. Sight and Hearing Association. Paul, MN Telephone: or The Occupational Safety and Health Administration OSHA mandates that employers provide hearing conservation programs for their employees in workplaces where noise levels equal or exceed 85 dB A for an eight-hour time-weighted average. An occupational hearing conservation program includes engineering and administrative controls to reduce noise exposures, employee training in the use of hearing protection and annual audiometry for all workers who are exposed to noise.

Physicians providing occupational health services to a company may supervise the hearing conservation program, review abnormal audiograms and advise the program administrator. The U. Preventive Services Task Force recommends periodic screening of older adults for hearing impairment. Standardized questionnaires for hearing handicap are available Figure 3.

Identification of elderly people with hearing problems. ASHA ;— If the clinician suspects hearing loss, a careful history of symptoms such as hearing loss, discharge, tinnitus and vertigo should be obtained; the ears should then be examined, and audiometry performed. The physical examination of the ears should assess presence of cerumen impaction or evidence of middle ear disease.

The Weber and Rinne tests, performed with a Hz or 1,Hz tuning fork can provide clues to whether the loss is conductive or sensorineural. In the Weber test Figure 4 , sound will lateralize to the side away from a sensorineural loss and toward a conductive deficit. The Rinne test Figure 5 will demonstrate air conduction better than bone conduction if the loss is sensorineural.

If available, office tympanometry can also help detect conductive hearing problems. Weber test. The physician can clarify this test by performing the test on himself or herself, plugging one ear with a finger to simulate a conductive loss. The Weber test is only useful if there is an asymmetric hearing loss. If hearing is symmetric, the patient perceives the sound in the middle of the forehead.

Rinne test. Holding a Hz or 1,Hz vibrating tuning fork against the mastoid process, the physician asks the patient to indicate when the sound can no longer be heard.