In terms of our ability to communicate with others, hearing is our most critical sense.
Even relatively mild hearing loss can seriously disrupt how we interact and connect with others. Without healthy hearing, the consequences for our social and mental health — and physical health, in some cases — become greater, and overall quality of life can plummet.
Healthy hearing requires a number of processes in the inner ear and brain to work properly in order to correctly interpret the sounds you hear. Inner-ear problems, or ear problems in general, can prevent crucial pieces of sound information from reaching the brain, leading to confusion and an inability to understand what is being said.
Commonly, an ear problem in the outer or middle ear is referred to as a conductive hearing loss, while inner-ear problems or brain-processing difficulties are referred to as sensorineural hearing loss. These are two distinct types of hearing loss with differing treatment methods.
Why Binaural Hearing Is Important
Binaural hearing refers to the brain’s ability to integrate information from both ears at once, which greatly improves overall communication and the ability to understand where sounds come from in relation to your body’s position. Hearing with both ears helps us to listen in noisy, complex environments and to hear speech sounds in noise.
It’s difficult to get by with only one healthy ear (unilateral hearing loss), particularly in educational settings. For example, children with unilateral hearing loss are far more likely to be forced to repeat a grade. Additionally, individuals with unilateral hearing loss find that speech comprehension suffers greatly, falling to only about 30 to 35 percent of what can be heard with two healthy ears.
The 3 Primary Types of Hearing Loss
Sensorineural Hearing Loss (SHL): SHL is typically the result of damage to the delicate hair cells in the inner-ear organ (the cochlea) that are responsible for picking up sounds. When these hair cells — or the nerves they connect to — are damaged or destroyed by repeated exposure to loud noise, hearing becomes more difficult. Because hearing damage usually affects the highest frequencies first, loud-noise exposure can result in permanent high-frequency hearing loss.
What Is Sensorineural Hearing Loss?
Sensorineural hearing loss refers to any reduction in hearing sensitivity or sound clarity that is caused by damage to the delicate structures of the inner ear or the nerve pathways that carry the sound signal from the inner ear to the auditory-processing area of the brain. Sensorineural hearing loss is the most common type of hearing loss and affects 28 million Americans.
Sensorineural hearing loss is usually cumulative and occurs slowly. Exposure to very loud noise is the most common cause of sensorineural hearing loss, followed by aging (presbycusis). Certain medications and health conditions such as diabetes and heart disease are also known causes of sensorineural hearing loss.
Hearing aids are the primary treatment for sensorineural hearing loss as medical or surgical intervention is rarely possible. Correctly fit hearing aids stimulate the affected nerves in the inner ear and fill in the Sound Voids that most sufferers experience. Today’s hearing aid technology can even address “high-frequency” sensorineural hearing losses that were once thought to be untreatable. If hearing loss is severe, a cochlear implant may be recommended.
Since sensorineural hearing loss is often caused by exposure to loud noises, we highly recommend the use of hearing protection if you find yourself around loud noises frequently. If you are diabetic, keep your blood glucose levels well controlled. A healthy diet and regular exercise are necessary to prevent the onset of heart disease and other medical problems that are also identified with hearing loss. A healthy lifestyle, excellent nutrition, and the use of well-fit hearing protection will help you hear for life.
Conductive Hearing Loss: This type of hearing loss is typically the result of an infection or blockage in the outer or middle ear. Otitis media (middle-ear infections) can sometimes cause difficulty hearing due to a fluid buildup. Swimmer’s ear or a buildup of earwax may create a blockage outside the eardrum. This type of hearing loss is typically reversible once the infection or blockage clears, or once necessary surgery is performed.
What Is Conductive Hearing Loss?
A conductive hearing loss occurs when there is a problem with one or more of the parts of the ear that conduct sound into the inner ear.
The ear canal, the eardrum, and the tiny bones in the middle ear make up the conductive system, and any hearing loss caused by a problem in one or more of these areas is called a conductive hearing loss.
Unlike a sensorineural hearing loss, a conductive hearing loss occurs because the sound entering the ear is reduced or dampened by the obstruction; there is no damage to the delicate nerves in the inner ear.
A conductive hearing loss can often be partially or completely reversed with medical intervention.
There are many potential causes of conductive hearing loss, with some causes being easier to treat than others.
Malformation of the outer- or middle-ear structures, a middle-ear infection in which fluid accumulates behind the eardrum, abnormal bone growth in the middle ear, a hole in the eardrum, or poor Eustachian tube function may be responsible for conductive hearing loss.
Rarely, there may be more serious causes of conductive hearing loss, and these conditions, if left unidentified and untreated, may have profound medical consequences.
Treatment for conductive hearing loss varies based on the circumstances. Antibiotics or antifungal medications are usually prescribed for ear infections, whereas surgery is usually an option for malformed or abnormal outer- or middle-ear structures and other physical problems.
Hearing aids are often the best answer when surgery is not possible, because they significantly improve hearing and are convenient.
Though usually not necessary, implantable hearing devices such as a bone-anchored hearing aid are an excellent alternative if neither surgery nor a traditional hearing aid are feasible options.
Mixed Hearing Loss: Individuals with mixed hearing loss typically suffer from some combination of SHL and a semipermanent conductive hearing loss, such as a malfunction of one of the ossicles (tiny bones that conduct sound) in the middle ear. Hearing may improve after the conductive portion of the hearing loss is resolved through treatment or surgery. SHL is usually permanent.
What Is Mixed Hearing Loss?
When both conductive and sensorineural hearing loss are present at the same time and in the same ear, it is referred to as mixed hearing loss or “combined-type” hearing loss.
In this case, there is likely to be damage to the outer or middle ear as well as to the inner ear or auditory nerve.
Causes of mixed hearing loss vary wildly. Typically, the sensorineural hearing loss is already present, and the conductive hearing loss develops later and for an unrelated reason. Very rarely, a conductive hearing loss can cause a sensorineural hearing loss.
As with sensorineural and conductive hearing losses, only a thorough diagnostic hearing and medical evaluation can identify a specific cause.
Medication or surgery may be the answer to the conductive portion of the mixed hearing loss, but these interventions cannot treat the sensorineural portion of the hearing loss.
Many people who suffer from a mixed hearing loss will receive medical treatment for the conductive hearing but will have to use a hearing aids to treat the remaining sensorineural component of their hearing loss.
Mild to severe sensorineural hearing loss can be helped through the use of hearing aids.
Other Forms of Hearing Loss
- Unilateral Hearing Loss: Hearing loss that occurs in only one ear is referred to as unilateral hearing loss. This can be present at birth, may happen spontaneously, or can occur over the course of several days (referred to as sudden hearing loss). Unilateral hearing loss may delay or otherwise affect speech and language development, and children may have difficulty identifying where sounds are coming from (localization), hearing speech in noisy situations, and hearing from longer distances. Children who are born with unilateral hearing loss can achieve success academically, economically, and socially by focusing on communication development.
- Sudden Hearing Loss: This is a sudden loss of hearing, either entirely or partially, within a 24-hour period — or immediately. Degrees of deafness vary, and while sudden hearing loss typically resolves itself within two weeks, it’s possible that hearing may never return. Treatment may include steroids to support the recovery of hearing, but patients who see no change within two weeks are unlikely to see improvement. Those who suffer from a sudden hearing loss should consult their physician immediately, as faster treatment greatly increases chances of a full recovery. About 85 percent of those who seek treatment will recover some of their hearing.
- High-Frequency Hearing Loss: Those with high-frequency hearing loss can usually hear vowels just fine, but consonant sounds — like f, s, t, and z — become difficult to hear. High-frequency hearing loss is often difficult to diagnose, because it occurs slowly over several decades, like most forms of sensorineural hearing loss. Early signs are an inability to hear higher-octave sounds, like a bird chirping or the voice of a woman or small child. Difficulty conversing in groups or hearing speech in background noise also indicate the possibility of a high-frequency hearing loss. Using hearing protection prior to being exposed to loud noises will help prevent high-frequency hearing loss, while hearing aids are an effective treatment.