Type of Hearing Loss

Type of Hearing Loss

Approximately 37.5 million Americans suffer from hearing loss. 1

Hearing loss affects people of all ages—one in eight people over 12 years of age in the United States has significant hearing loss2. Hearing loss is the third most common health problem in the United States. Untreated hearing loss can affect your ability to understand speech and can negatively impact your social and emotional well-being—hearing impairment can decrease your quality of life!

Signs you may have a hearing loss:

  • Difficulty hearing people in noisy environments such as a restaurant, shopping mall, in cars, or at the movie theater.
  • People seem to "mumble" all the time.
  • Family, friends, or colleagues often need to repeat themselves when speaking with you.
  • You have trouble hearing people when they are not facing you or are in another room.
  • You have trouble following conversations.
  • You have ringing, buzzing, or hissing sounds in your ears.

What causes hearing loss?

  • Exposure to excessive loud noise.
  • Ear infections, trauma, or ear disease.
  • Damage to the inner ear and ear drum from contact with a foreign object (cotton swabs, bobby pins, etc.).
  • Illness or certain medications.
  • Deteriorating hearing due family history, noise exposure, or age.

How to protect your hearing:

  • Wear hearing protection when around loud sounds. There are different types of hearing protection such as foam earplugs, earmuffs and custom hearing protection devices. Contact your local audiologist for custom hearing protection devices.
  • Turn down the volume when listening to the radio, the TV, MP3 player, or anything through ear buds and headphones.
  • Walk away from the noise.
  • And, other than hearing protection, do not put anything in your ear!

Reference

  1. Blackwell DL, Lucas JW, Clarke TC. Summary health statistics for U.S. adults: National health interview survey, 2012 (PDF). National Center for Health Statistics. Vital Health Stat 10(260). 2014.
  2. Lin FR, Niparko JK, Ferrucci L. Hearing loss prevalence in the United States. Arch Intern Med. 2011 Nov 14; 171(20): 1851-1852.

Did you know there is more than one type of hearing loss? Changes to different parts of the hearing system will result in one of three types of hearing loss: sensorineural, conductive, or mixed.

Types of Hearing Loss Sensorineural Hearing Loss

Sensorineural hearing loss (SNHL) results from changes in the inner ear (cochlea) and/or the auditory nerve. More often than not, these changes cause permanent hearing loss that is not treatable with medicine or surgery. Some of the known causes of SNHL include the following: age, noise exposure, genetics, malformations of the inner ear, benign tumor, illnesses, medications known to be toxic to the ear, and injury/trauma. Hearing aids are a common solution used to assist with this type of hearing loss.

Conductive Hearing Loss

Conductive hearing loss (CHL) results from changes in the outer ear and/or middle ear. With a CHL, sound is not able to travel (be conducted) efficiently down the ear canal, through the eardrum, and along the ossicles (middle ear bones). Some of the more common causes of CHL include the following: fluid in the middle ear, ear infection in either the outer and/or middle ear space, allergies, a hole in the eardrum, ear wax (cerumen) blockage, benign tumor, a foreign object in the ear canal, and the absence or malformation of the outer and/or middle ear. This type of hearing loss is often corrected with medical management or surgery. In some cases, hearing aids may be recommended.

Mixed Hearing Loss

Mixed hearing loss (MHL) results from the presence of both a SNHL and CHL at the same time. For example, a person with noise-induced SNHL may get a head cold that causes fluid in the middle ear. During the time the fluid is present, a CHL is occurring in addition to the already present SNHL. Sometimes MHL can improve with medical management, while other times, it is permanent.

How is Hearing Loss Diagnosed?

Hearing loss is diagnosed with a battery of tests that determines how soft you can hear and how well sound travels through the auditory system. The test battery may include, but is not limited to audiometry, tympanometry, acoustic reflex thresholds, speech-in-noise testing, and otoacoustic emissions. Typically, the audiologist completes the testing in a sound booth or sound treated room. Some tests require you to sit quietly while others require your participation. The audiologist will be able to determine if you have hearing loss and if so, the type and degree of hearing loss on the day of your evaluation.

It is estimated that the annual incidence of sudden sensorineural hearing loss is 1 in 5000 people or about 4000 new cases per year in the US 1.

Sudden sensorineural hearing loss is defined as a rapid onset of hearing loss over a 72-hour period. It usually occurs in one ear and can be associated with other symptoms such as dizziness and ringing in the ear (tinnitus). It can affect people at any age, but it is most common in adults between 50-60 years of age.2 Sudden sensorineural hearing loss is a serious condition and should be treated as a medical emergency.

A comprehensive hearing test performed by an audiologist can help to diagnose sudden sensorineural hearing loss. In addition, a thorough work up performed by an Ear, Nose, and Throat physician is necessary. Further testing may include an MRI, blood tests, and balance tests.

Causes of sudden sensorineural hearing loss.

Ninety percent of sudden sensorineural hearing loss cases are idiopathic, meaning the cause is unknown. It is suspected that there may be an injury to the hearing organ (cochlea) that causes swelling or blockage of blood flow. Many cases of sudden sensorineural loss happen after a person has suffered from a viral or bacterial infection. 1, 2 Other reported causes of sudden sensorineural hearing loss include autoimmune disease, lime disease, acoustic neuromas and multiple sclerosis.

Treatment of sudden sensorineural hearing loss

Medical treatment should be obtained as soon as possible to better the prognosis of sudden sensorineural hearing loss. The most common treatment is a course of corticosteroids such as oral prednisone and/or intra-tympanic steroid injections. The majority of people with sudden sensorineural hearing loss will recover some degree of the loss and small percentage of people will have symptoms that worsen. 2,3

After treatment, if hearing loss remains, then hearing aids, implantable devices and/or assistive listening technology can help manage the residual hearing loss.

If you suspect that you may have sudden sensorineural hearing loss, seek medical help right away.

References

  1. Sudden Deafness NIH Pub. No. 00-4757 July 2013
  2. Wazen and Ghossaini; Hearing Review, December 2003, Sudden Sensorineural Hearing Loss special issue;
  3. Kuhnn et al; Sudden Sensorineural Hearing Loss; September 2011; A Review of Diagnosis, Treatment, and Prognosis.

What is Hidden Hearing Loss?

Hidden hearing loss a relatively new term. It describes hearing loss that cannot be measured by standard hearing tests, even though patients report difficulty hearing, especially in background noise.

How is hidden hearing loss measured?

There is no standard test protocol to detect hidden hearing loss. A person with hidden hearing loss may have normal results on a standard hearing test battery. An audiologist may elect to do additional testing that evaluates a patient's hearing abilities in the presence of background noise to better understand the patient's difficulty.

The cause of Hidden Hearing loss

There is still plenty of research to be done in this area, but initial research suggests that hidden hearing loss is caused by damage to cells in the hearing organ (cochlea) in the inner ear. These cells connect the hearing organ to the brain. Once damaged, these cells are no longer able to send information to the brain. This can cause the brain to not receive a clear sound signal and to not interpret the sound correctly.

What to do if you think you have hidden hearing loss.

If you suspect that you may have a hearing loss, then you should schedule an appointment with an audiologist for further evaluation. If hidden hearing loss is suspected, communication strategies and assistive listening devices may be used to help in difficult listening situations.

Protecting your hearing is the most important step in preventing hidden hearing loss. What steps can you take to prevent hidden hearing loss?

  • Wear proper hearing protection (earmuffs, earplugs) when in noisy environments such as: concerts, sporting events, fireworks displays, and car races. Hearing protection comes in a variety of sizes and textures to provide optimal fit. Custom-made earplugs can be obtained from an audiologist.
  • Set volume limits on your portable devices.
  • Walk away from loud sounds.

References

Otman, H. (2017, Feb 28) Second Cause of Hidden Hearing Loss Identified- Hearing Research By Michigan Medicine.

It is estimated that half of children born with hearing loss have a genetic cause.1 Genes make up DNA -units of heredity that are passed from parents to children. If a gene does not form normally, it is called a mutation. Some of these mutations cause hearing loss.

Genetic hearing loss can be the result of non-syndromic or syndromic genetic mutations. Non-syndromic hearing loss is a hearing loss that occurs with no other symptoms. These mutations account for about 70% of cases of genetic hearing loss. Non-syndromic hearing loss can vary from person to person, even within the same family. Hearing loss can affect one (unilateral) or both (bilateral) ears and can range from mild to profound degrees of hearing loss. The hearing loss may also be stable or progressive, meaning that it can change over time.

Non-syndromic hearing loss is inherited in one of the following patterns:

  1. Autosomal recessive
  2. Autosomal dominant
  3. X-linked
  4. Mitochondrial
  1. In an autosomal recessive inheritance pattern, the mutated gene is inherited from each parent. Most instances of non-syndromic hearing loss are inherited through an autosomal recessive pattern. There are currently more than 60 known genes that can cause autosomal recessive non-syndromic hearing loss. The most common cause of autosomal recessive non-syndromic hearing loss is because of a genetic mutation in the GJB2 gene which is a member of the Connexin protein family.2
  2. An autosomal dominant inheritance pattern occurs when the mutated gene is inherited from only one parent. More than 30 genes have been associated with autosomal dominant non-syndromic hearing loss.2
  3. In an X-linked inheritance pattern, the mutated gene on the X chromosome passes from the mother to the son and results in male children having a hearing loss. Approximately half of X-linked non-syndromic hearing losses are the result of a mutation in the POU3F4 gene.2 There have also been mutations identified in at least 3 others genes.
  4. Mitochondrial genetic disorders are caused by mutations in DNA. Very few mutations have been identified in mitochondrial non-syndromic hearing loss and their role in hearing and hearing loss is still being studied.

References

  1. "Hearing Loss in Children." Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 18 Feb. 2015.
  2. "Nonsyndromic Hearing Loss - Genetics Home Reference." U.S. National Library of Medicine, National Institutes of Health, 6 Feb. 2018.

Age-Related Hearing Loss

One in three people older than age 60 have hearing loss; one in two people older than age 85 have hearing loss.1

Hearing loss related to age is called presbycusis. It is a combination of changes to the

  • Structures of the inner ear
  • Blood flow to the inner ear
  • Hearing nerve
  • How the brain processes speech and sound

Presbycusis typically is a high-pitched hearing loss that can be noticed by subtle changes in hearing over time.

Common Signs of Hearing Loss

  • Asking people to repeat what they say.
  • Feeling like others are always mumbling or not speaking clearly.
  • Difficulty hearing or understanding speech in noisy environments.
  • Missing words or phrases on the telephone.
  • Turning the volume up on the television or radio louder than normal.

Hearing loss due to aging can be worsened by other factors such as diabetes, poor circulation, noise exposure, and certain medications.

  • 25 percent of adults between the ages of 65 and 75 years suffer from hearing loss.1
  • 50 percent of adults 75 years and older suffer from hearing loss.1

Prevention

Although hearing loss with age is common, there are some steps you can take to prevent your hearing loss from getting worse. Daily considerations include avoiding loud sounds and using ear protection when exposed to loud sounds.

The "use it or lose it" principle applies to our ears. Unmanaged hearing loss can lead to deteriorated understanding of speech over time. Dealing with hearing loss early rather than later or putting it off is highly recommended.

People with unmanaged hearing loss often experience a decreased quality of life. Unmanaged hearing loss can lead to sadness, depression, anxiety, paranoia, and poor social relationships. Hearing loss can also lead to more fatigue because of your increased effort to understand speech.

Hearing loss is managed using technology and improving communication strategies. Your audiologist can help you determine if hearing aids, cochlear implants, or other assistive listening devices are appropriate for you.

References

National Institute on Deafness and Other Communicative Disorders (NIDCD)

Facts about Noise-Induced Hearing Loss

Approximately 40 million American adults may have hearing loss resulting from noise exposure. Noise-induced hearing loss is caused by damage to the hair cells found in the inner ear. Hair cells are small sensory cells that convert the sounds we hear (sound energy) into electrical signals that travel to the brain. Once damaged, our hair cells cannot grow back, which results in permanent hearing loss.

Hearing protection decreases the intensity, or loudness, of noise and helps preserve your hearing.

Harmful sounds are those that are too loud and last too long or are very loud and sudden. For example, exposure to a one-time intense "impulse" sound such as an explosion, or continuous exposure to loud sounds over an extended period of time such as at a concert may be harmful. The louder the sound, the shorter the amount of time you can safely be around it.

You may encounter harmful sounds at work, at home, and during recreational activities. If you work in a hazardous noise environment, speak to your supervisor or compliance officer about OSHA recommendations on your amount of noise exposure.

Sound is dangerous if:

  • You have to shout over background noise to be heard
  • The noise is painful to your ears
  • The noise makes your ears ring
  • You have decreased or "muffled" hearing for several hours after exposure

Noise-induced hearing loss can be caused by sudden or prolonged exposure to any sound over 85 dB. Sound loudness is measured in units called decibels (dB).

60 dB

Normal conversations, dishwashers

80 dB

Alarm clocks

90 dB

Hair dryers, blenders, lawnmowers

100 dB

MP3 players at full volume

110 dB

Concerts (any music genre), car racing, sporting events

120 dB

Jet planes at take off

130 dB

Ambulance, fire engine sirens

140 dB

Gun shots, fireworks, custom car stereos at full volume

Protect your hearing:

  • Wear hearing protection when around sounds louder than 85 dB.  There are different types of hearing protection such as foam earplugs, earmuffs, and custom hearing protection devices
  • Contact your local audiologist for custom hearing protection devices.  These include special hearing protection for musicians and hunters.
  • Turn down the volume when listening to the radio, television, MP3 player, or anything through earbuds and headphones.
  • Walk away from the noise.

National Institute on Deafness and Other Communication Disorders (NIDCD)

Do you think you or someone you know may have a hearing loss? Find an audiologist.