Hearing Loss 101
Signs of Hearing Loss
The signs of hearing loss can be subtle and emerge slowly, or early signs of hearing loss can be significant and come about suddenly. Either way, there are common indications and hearing impaired signs. You should suspect hearing loss if you experience any of the signs below.
- require frequent repetition.
- have difficulty following conversations involving more than 2 people.
- think that other people sound muffled or like they're mumbling.
- have difficulty hearing in noisy situations, like conferences, restaurants, malls, or crowded meeting rooms.
- have trouble hearing children and women.
- have your TV or radio turned up to a high volume.
- answer or respond inappropriately in conversations.
- have ringing in your ears.
- read lips or more intently watch people's faces when they speak with you.
- feel stressed out from straining to hear what others are saying.
- feel annoyed at other people because you can't hear or understand them.
- feel embarrassed to meet new people or from misunderstanding what others are saying.
- feel nervous about trying to hear and understand.
- withdraw from social situations that you once enjoyed because of difficulty hearing.
- have a family history of hearing loss.
- take medications that can harm the hearing system (ototoxic drugs).
- have diabetes, heart, circulation or thyroid problems.
- have been exposed to very loud sounds over a long period or single exposure to explosive noise.
Types of Hearing Loss
A comprehensive audiologic evaluation must be completed in order to determine the types and severity of hearing loss to make appropriate recommendations for each patient. Audiologic data from testing provides a clinical foundation for recommendations on hearing aids and other assistive devices suitable for treating the types of hearing impairments listed below.
In general terms, there are two types of hearing loss, conductive and sensorineural. A combination of both is also seen as a mixed hearing loss. Each is discussed below.
Conductive Hearing Loss:
Conductive hearing loss is caused by any condition or disease that impedes the conveyance of sound in its mechanical form through the middle ear cavity to the inner ear. A conductive hearing loss can be the result of a blockage in the external ear canal or can be caused by any disorder that unfavorably effects the middle ear's ability to transmit the mechanical energy to the stapes footplate. This results in reduction of one of the physical attributes of sound called intensity (loudness), so the energy reaching the inner ear is lower or less intense than that in the original stimulus. Therefore, more energy is needed for the individual with a conductive hearing loss to hear sound, but once it's loud enough and the mechanical impediment is overcome, that ear works in a normal way. Generally, the cause of conductive hearing loss can be identified and treated resulting in a complete or partial improvement in hearing. Following the completion of medical treatment for cause of the conductive hearing loss, hearing aids are effective in correcting the remaining hearing loss.
The audiometric profile that indicates a conductive hearing loss is the presence of air-bone gaps (better hearing by bone conduction than by air conduction), excellent word recognition at a comfortable listening level, and evidence of a middle ear dysfunction on immittance. For situations where a blockage is noted in the external ear canal, hearing testing is deferred until the canal is cleared.
Sensorineural Hearing Loss:
The second type of hearing loss is called sensorineural hearing loss. This word can be divided into its two components - sensory and neural - to allow us more clarity in specifying the type of hearing loss. The comprehensive audiometric assessment and supplemental tests can yield the information needed to differentiate between a sensory and a neural hearing loss, although they can co-exist in the same ear. Neural hearing loss is another name for retrocochlear hearing loss.
Sensorineural hearing loss results from inner ear or auditory nerve dysfunction. The sensory component may be from damage to the organ of Corti or an inability of the hair cells to stimulate the nerves of hearing or a metabolic problem in the fluids of the inner ear. The neural or retrocochlear component can be the result of severe damage to the organ of Corti that causes the nerves of hearing to degenerate or it can be an inability of the hearing nerves themselves to convey neurochemical information through the central auditory pathways.
The reason for sensorineural hearing loss sometimes cannot be determined, it does not typically respond favorably to medical treatment, and it is typically described as an irreversible, permanent condition. Like conductive hearing loss, sensorineural hearing loss reduces the intensity of sound, but it might also introduce an element of distortion into what is heard resulting in sounds being unclear even when they are loud enough. Once any medically treatable conditions have been ruled out, the treatment for sensorineural hearing loss is amplification through hearing aids.
Mixed Hearing Loss:
A mixed hearing loss can be thought of as a sensorineural hearing loss with a conductive component overlaying all or part of the audiometric range tested. So, in addition to some irreversible hearing loss caused by an inner ear or auditory nerve disorder, there is also a dysfunction of the middle ear mechanism that makes the hearing worse than the sensorineural loss alone. The conductive component may be amenable to medical treatment and reversal of the associated hearing loss, but the sensorineural component will most likely be permanent. Hearing aids can be beneficial for persons with a mixed hearing loss, but caution must be exercised by the hearing care professional and patient if the conductive component is due to an active ear infection.