Hearing loss affects individuals of all ages, ethnicities, and lifestyle habits. The different types of hearing loss also have various degrees of impairment, in addition to the unique configurations seen. The various types of hearing loss have different causes, may have different severities, and may have different treatments available.
Asking what type of hearing loss do I have and searching for an answer may require the assistance of a doctor. However, there are key indicators that can aid in the process of figuring it out.
Here, we will differentiate among the types of hearing loss to give insight into what causes each, what defines each type, and what the forms of treatment are. Individuals can compare the listed symptoms and causes to see if any reflect their given circumstances.
How Many Types of Hearing Loss Are There?
Different organizations recognize different numbers of hearing loss. Some report three distinct types of hearing loss, whereas others state there are 4 types. The Center for Disease Control recognizes four main types which are conductive hearing loss, sensorineural hearing loss, mixed hearing loss, and auditory neuropathy spectrum disorder.
Reported by the Johns Hopkins Cochlear Center for Hearing and Public Health, over 14% of adults suffer from some form of hearing loss.
Conductive Hearing Loss
Conductive hearing loss is characterized by having an obstruction or damage to the middle portion of one’s ear, which leads to a struggle in proper hearing.
Alternatively, an obstruction may persist in the outer ear which still blocks sounds from reaching the inner ear. Conductive hearing loss is typically unilateral, meaning it only affects one ear.
Conductive hearing loss typically does not cause complete hearing loss. Rather, individuals with conductive hearing loss have trouble hearing the loudness of sounds. Patients may struggle with hearing quiet sounds, voices, or quiet signals. Other symptoms may include the following.
- Pain in the affected ear
- Frustration due to a struggle to hear quiet sounds
- Pressure sensations in the affected ear
- Better hearing in one ear versus the other
- Hearing one’s voice louder
- Muffled hearing
- Ringing in one’s ear—tinnitus
Often, individuals have a wax buildup inside their ear, which hinders sound waves from reaching the necessary parts of the inner ear. Other causes include obstructions stuck in the ear, swimmer’s ear, the narrowing of one’s ear canal—stenosis, or ears that do not fully develop.
Causes that affect the middle ear include abnormal growths of tissue, like a tumor, an injury to the tympanic membrane, extreme ear infections, rapid air pressure changes, a buildup of fluid in the ear, thickening of the tympanic membrane, otosclerosis, blockage of the eustachian tube, or disconnection between the bones of the middle ear from injury or trauma.
Treating an individual for conductive hearing loss can prove difficult if the cause is undetermined. However, once the cause is brought to light, treatment is often easy and painless. For an individual with an obstruction or earwax buildup, an ENT specialist can clean out one’s ears and remove any obstructions or wax buildups.
If the cause of the hearing loss is due to an infection, medication can fight the infection and help to regain hearing. For individuals with permanent conductive hearing loss—from damage or other—hearing aids may be the best treatment.
Sensorineural Hearing Loss
Sensorineural hearing loss is the most common type of permanent hearing loss. This type of hearing loss happens when damage is present in the inner ear, specifically the small hair cells.
Less common, damage to the auditory nerve may occur resulting in sensorineural hearing loss. Sensorineural hearing loss can affect one or both ears, depending on the causes.
Individuals with sensorineural hearing loss struggle with hearing the loudness and the clarity of the sounds. Most patients can hear others speak, but they cannot understand the speech clearly. Patients with a severe degree of sensorineural hearing loss often may be incapable of recognizing voices and common sounds in everyday life. Other symptoms include the following.
- Other’s speech is muffled, slurred, or generally unintelligible
- Difficulty in communicating
- Ringing sensation—tinnitus
- Unable to differentiate sounds in loud and noisy environments
- Occasional feelings of dizziness
- Difficulty hearing high-pitch sounds (children’s voices)
Various causes of sensorineural hearing loss exist, such as genetic diseases that cause children to be born with it. However, most often, aging is the reason for sensorineural hearing loss.
The medical term for age-related hearing loss is presbycusis. This occurrence is characterized by the degeneration of the inner ear’s hair cells. When these hair cells no longer function adequately, sound waves cannot properly process sound waves into electrical signals.
Another main cause of sensorineural hearing loss is damage to the inner ear from exposure to loud noises. The injury and damage can happen gradually, over time, or suddenly, from one excessively loud noise.
Individuals working in factories or warehouses where consistent loud noises occur have a greater risk for developing sensorineural hearing loss. Similarly, military members have high risks due to their involvement with frequent loud noises.
Some other less common causes include the following.
- Side effect from various medicine
- Autoimmune disease
- Bacterial or viral infection side-effects
- Meniere’s Disease—swelling and pressure in the inner ear
- Acoustic Neuroma—a benign brain tumor that develops on the nerve responsible for hearing and balance
As sensorineural hearing loss is permanent, no treatments to regain hearing exist. Damage to hair cells or other inner ear structures is irreparable.
Individuals can receive treatment in the form of hearing aids or cochlear implants to supplement their loss of hearing. Other options include listening devices that alert the affected individual either with loud noise, light, or vibration.
Mixed Hearing Loss
As the name sounds, mixed hearing loss is a mix of both conductive and sensorineural hearing loss. Individuals may have a combination of both. For example, an individual may struggle with age-related hearing loss through natural degeneration of hair cells while an ear infection or other cause exacerbates the problem. Mixed hearing loss may one or both ears, depending on the causes.
The symptoms of mixed hearing loss are similar to the two types discussed above. Individuals will struggle with hearing the loudness of sounds and the clarity of sounds. Other symptoms include the following.
- Difficulty communicating with others
- Difficulty hearing two people talk
- Trouble differentiating voices or sounds in loud environments
- Pressure sensations in the affected ear(s)
- Frustration with hearing
Depending on the predominant type of hearing loss, the causes will differ. An individual struggling with presbycusis who suffers from some sort of physical trauma can often develop mixed hearing loss. Other causes include ear wax buildups, physical obstructions, ear infections, abnormal growths, or injury to the eardrum.
Treating mixed hearing loss can prove difficult until doctors can definitively establish what the primary cause of the hearing loss is. If the majority of hearing loss is conductive, procedures to remove blockages, treat infections, or other medical treatments may prove effective.
However, if the primary source of loss is from sensorineural hearing loss, treatments are fewer. In this case, patients will likely have to use hearing aids to treat their hearing loss.
Auditory Neuropathy Spectrum Disorder
This form of hearing loss is significantly different from other types. Auditory neuropathy spectrum disorder is a form of hearing loss where the patient can receive sound waves successfully, but the signals cannot be sent properly to the brain.
Essentially, this form of hearing loss is resultant of ineffective neural transmission. The disorder can affect individuals of all ages. Children affected by the condition may struggle the most due to not understanding the reasons they cannot hear and communicate.
The disorder is diagnosed by utilizing an auditory brainstem response test and an otoacoustic emissions test. The first measures brain activity in response to sound. The second determines if the ear’s hair cells are functioning properly. If the hair cells seem to be function, but the ABR test is abnormal, doctors can confidently diagnose the patient with auditory neuropathy.
Similar to other types of hearing loss, individuals with auditory neuropathy cannot head the loudness of sounds well. They may also have trouble with the clarity of sounds. Additionally, depending on the case, some individuals may have sounds fade in and out. Other symptoms include the following.
- Difficulty understanding speech
- Difficulty paying attention to conversations
- Frustration with communication
Causes of auditory neuropathy spectrum disorder remain elusive. The condition can result from damage to the inner hair cells, as these cells assist in sending signals to the brain. Damage to the auditory neurons may also cause the condition as these neurons carry the sound from the hair cells to the brain. Lastly, auditory neuropathy may occur as a result of genetic mutations.
Treating an individual with auditory neuropathy remains difficult. Some doctors find prescribing hearing aids or cochlear implants is the best treatment option. Other listening devices such as Telcoil aids, FM systems, or alerting devices may be optimal.
If a child is diagnosed with auditory neuropathy spectrum disorder, doctors recommend the child learns sign language to communicate effectively.