The Sense of Hearing

The ability to hear is a gift we don't value enough. It is such an integral part of life that people often take it for granted. Correcting hearing loss can significantly improve the quality of life.

Signs of Hearing Loss

About 1 in 10 people has some degree of hearing loss. It tends to develop slowly, so you may gradually adjust to reduced hearing, and not notice much. Think about it for a moment. You may have a hearing loss if:

  • family complain the TV or radio is too loud
  • people seem to mumble when they speak
  • you hear people speaking, but can't quite understand what they are saying
  • you ask people to repeat what they said more often
  • understanding conversation in a group or noisy restaurant is more difficult for you than for others
  • listening intensely is frustrating and tires you quickly
  • people say you talk loudly
  • you have a hard time telling where sounds are coming from
  • your ears ring or roar
How Do We Hear?

Sound is collected by the outer visible part of the ear and travels through the ear canal. It then strikes the eardrum, causing it to vibrate.  This vibration causes the three tiny bones in the middle ear space to vibrate. The bones mechanically increase the sound pressure level as they conduct the sound through the middle ear space (normally filled with air) to the membrane at the entrance of the inner ear.

The inner ear is a fluid and membrane filled space hollowed out of bone in the skull. As the first membrane is vibrated, the inner ear fluid starts to move, causing movement of another membrane that has tiny nerve endings attached. This converts the sound into an electrical impulse, which the nerve endings pass on to the auditory nerve. The nerve sends it to the brain for processing. 

Courtesy of the Better Hearing Institute, a tour of the ear video is available here:

Ear diagram
Types and Causes of Hearing Loss

Conductive: This type of hearing loss is due to a blockage or reduction of sound transmission through the ear canal or middle ear space. Hearing may be impaired for all or some pitches, often low pitches. Common causes include earwax buildup, a perforated eardrum, damaged middle ear bones, infection and fluid in the middle ear space. This fluid may develop due to swollen or blocked Eustachian tubes (an air passage between the middle ear space and the upper part of the throat, behind the nose). Colds or allergies can cause the Eustachian tube to swell, and enlarged adenoids can block the opening.

Conductive hearing loss is the most common type found in children, but is found in only about ten percent of adults. It can be a minimal, mild, moderate or moderately-severe degree of hearing loss, but it can usually be successfully treated or at least improved with medical or surgical treatment.

Sensorineural: This type of hearing loss is due to a problem with the inner ear nerve cells that create the electrical impulses or the auditory nerve that transmits them. They can be damaged by things like loud noise exposure, trauma, metabolic diseases that reduce blood flow or affect blood chemistry (hypertension, atherosclerosis, diabetes, etc.), autoimmune disorders, viruses, exposure to certain drugs, a genetic tendency for nerve cell degeneration with aging, or very rarely, a non-cancerous tumor (affecting the auditory nerve).

Most adult hearing loss is sensorineural. It can be any degree of hearing loss, and may affect some or all pitches (often high pitches). It is not usually able to be helped with medical or surgical treatment, but more than ninety percent of the time it can be improved with hearing aids. A cochlear implant—a device that can generate electrical impulses—is a surgical treatment which is only appropriate for severe to profound hearing losses that don't receive enough help from hearing aids.

Other Types of Hearing Loss: A mixed hearing loss has more than one cause, and is a combination of conductive and sensorineural hearing loss. Another type of hearing loss is central, which is a problem with the way the brain processes or interprets sound.

Diagnosis of Hearing Loss

Audiologists are the professionals trained to identify, treat, and prevent hearing loss. Their role is both a clinical and a counseling one. Holding a master's or doctoral degree, they are well qualified to diagnose the degree and type of hearing loss and to determine whether medical evaluation is necessary.  

A comprehensive hearing evaluation typically includes:

  • a review of personal and family hearing history
  • a review of medical history and medications that may affect hearing
  • an ear exam to rule out earwax, infection, and other ear canal or eardrum abnormalities (sometimes earwax may be removed)
  • pure tone thresholds—measurement of the softest level each ear can hear tones of various pitches, first with earphones and then with a device placed on the bony area behind your ear
  • speech recognition thresholds—measurement of the softest level each ear can understand speech (usually easy two-syllable words)
  • word recognition scores—measurement of the percentage of special one-syllable words each ear can understand when the volume is just right.

Sometimes the evaluation may include other painless procedures. These are the most common:

  • Most comfortable and uncomfortable listening levels—often done as a quick measure of whether the inner ears have an abnormal response to increases in loudness
  • tympanograms—measurement of how well the eardrums move, to determine the health status of the eardrum and middle ear space
  • acoustic reflex thresholds—determination of whether a protective reflex can be triggered by brief sounds at expected levels
  • reflex decay—a ten second measurement of the acoustic reflex to see if the muscle contraction it causes can be sustained over time
  • otoacoustic emissions—detection of tiny sounds produced by inner ear nerve cells in response to other sounds, to determine how well the inner ear functions

At the conclusion of the evaluation, the results will be reviewed with you, and recommendations will be made.

Prevalence of Hearing Loss
  • 1 out of 10 Americans have a hearing loss—that’s more than 31,000,000 people.
  • 3 out of 1000 children are born with hearing loss.
  • 1.4 million children have hearing loss.
  • 15% of “baby-boomers” (ages 45-64) have hearing loss.
  • 29% of people over age 65 have hearing loss.
  • The majority (65%) of people with hearing loss are below retirement age.
  • The majority (60%) of people with hearing loss are males.
Degrees of Hearing Loss

Hearing is measured in deciBels (dB) using tones of various pitches (pure tone frequencies labeled in Hertz, or Hz). Hearing loss may be labeled with one of the following degrees, but often the degree of hearing loss will be different for some pitches than for others. (Audiologists generally avoid classifying hearing loss using percent, as the percent of loss formula was developed for legal compensation reasons and is misleading for real life use.)

Normal (15dB or less in children, 25dB or less in adults) 

Minimal (16-25dB): A term used for hearing loss in children that might be called slight or borderline-normal in adults. The normal range is smaller in children, because their hearing needs to be very good during language and listening skills development. To reduce the risk of educational difficulties, children with minimal hearing loss may need treatment or monitoring.

Mild (26-40dB): A person with mild hearing loss typically is unable to hear soft sounds and has difficulty understanding speech in noisy environments. The term "mild" is a bit misleading. It doesn't mean treatment isn't needed. Mild hearing loss in children MUST be treated, as it can lead to language development or learning difficulties, and fatigue from straining to hear in the classroom. Adults with active lifestyles or demanding jobs will notice significant benefit from getting treatment for their mild hearing loss. Others adults may benefit socially and emotionally from staying in contact with all the little sounds of life that surround us.

Moderate (41-55dB): With moderate hearing loss, a person is unable to hear soft and moderately loud sounds and has considerable difficulty understanding speech, especially in background noise. Treatment is recommended for moderate or worse hearing loss.

Moderately-severe (56-70dB): A person with moderately-severe hearing loss is unable to hear normal level or slightly loud speech.

Severe (71-90dB): With severe hearing loss a person is unable to hear most sounds, and speakers must raise their voice considerably to be heard.

Profound (91dB or greater): A person with profound hearing loss may be able to hear some very loud sounds, but communicating is very difficult. When hearing loss is profound at most pitches, a person is often considered to be deaf.

Treatment of Hearing Loss

Medical and/or Surgical Treatment:

Audiologists will recommend medical evaluation as necessary, but as a general rule, see a physician right away if you have: 

  • pain or discomfort in one or both ears
  • active drainage from one or both ears
  • sudden or ongoing dizziness
  • sudden hearing loss in both, or especially in only one ear (you may have a rare kind of sensorineural hearing loss that might be helped with medication if started soon enough).

If medical evaluation is recommended, your primary care physician is usually a good place to start. He or she may be able to remove earwax, treat common disorders like ear infections, and determine whether referral to an ear specialist is necessary. An ear specialist (otologist or otolaryngologist) is primarily a surgeon, and can determine whether surgery is necessary. The specialist can also evaluate and treat more unusual ear disorders, and remove deeply impacted earwax.

Hearing Aids: If medical or surgical treatment won't help in your case, or doesn't help enough, the odds are that hearing aids will help. Ninety to ninety-five percent of sensorineural hearing loss can be helped with hearing aids, at least to some degree. About eighty percent of hearing aid users wear hearing aids in both ears. People often put off getting hearing aids, but once they have been successfully fit with hearing aids they don't want to be without them. Successful fitting requires careful selection, precise programming, counseling and follow-up fine-tuning as the brain adjusts to hearing well again. Please see our hearing aids page for a thorough discussion of this topic. You may also want to see the frequently asked questions section.

Assistive Listening and Alerting Devices: These devices help you with sounds and situations that you cannot hear, or hear well enough. Some of them supplement hearing aids, while others are used instead of hearing aids. Ask your audiologist about which devices may be appropriate for you and compatible with your hearing aids, if applicable.

Speechreading and Auditory Training: Speechreading is a term that means lip reading plus use of body language, context, and other cues. Only about thirty percent of speech sounds are visible on the lips. Some people become good speechreaders on their own, but it can also be taught.

Auditory training is often used to help hearing impaired children learn to make maximum use of their residual hearing, but it can also help adults tune into sounds they may otherwise miss.

Ask your audiologist about availability of classes or individual training in your area. There are also good videos available to help you learn speechreading skills.

Cochlear ImplantsCochlear Implants:  When hearing loss is severe or profound, and sensorineural, a cochlear implant may be recommended if hearing aids cannot help enough. This device consists of both external and internal (surgically implanted) components. External components include a microphone and digital sound processor (which often looks similar to a behind-the-ear hearing aid), and a transmitting coil (a little further behind the ear) that attaches magnetically to an internal component, a receiving coil under the skin. The other internal component is a partially coiled "array" of electrodes inserted into the inner ear.

A cochlear implant bypasses the damaged or missing nerve cells in the inner ear and directly stimulates surviving neurons in the auditory nerve. It does not restore normal hearing. Instead, it can give a deaf or severely hard-of-hearing person a useful representation of sounds in the environment and help him or her to understand speech.

Tinnitus relief

Tinnitus

Most of the time, tinnitus is the perception of sound that isn't really there. In rare cases, other people can hear it coming from your ear canal. Most people describe it as a ringing or buzzing sensation, or like "crickets." It can be quite bothersome. It is often associated with hearing loss. Although there are about 50 different causes of tinnitus, tinnitus and hearing loss are often both caused by exposure to loud sound. While there are no known cures, it is possible to get it to "fade away" so that it is not so bothersome. Use of hearing aids, when appropriate, often helps by giving the brain other sounds to focus on. Some hearing aids have sound generators built in that produce white noise (or pink noise, speech noise, ocean waves, etc.) that may be more pleasant to listen to and may give some relief from the tinnitus.

Over time, and with proper counseling and product programming, the tinnitus may cease being a problem. The first step is a medical quality hearing evaluation to try to determine the cause. Often having an ear, nose, and throat physician review the test results helps put your mind at ease. Once you know it isn't anything serious that needs medical treatment, you can learn to stop noticing it, like people who live next to a railroad track stop noticing the trains. It sounds difficult, but Dr. Boatz has been able to do it for her own case of tinnitus. Come get a hearing evaluation and talk to her about your tinnitus.

Contact us today to start your journey towards better hearing.

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Terre Haute, IN 47802

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