Table of Contents
- Three hearing loss types
- Sensorineural hearing loss
- Conductive hearing loss
- Mixed hearing loss
- Effects of hearing loss
- Gradual and sudden hearing loss treatments
Disabling hearing loss affects 5% of the world’s population — 466 million people, more than the population of the U.S. — and the World Health Organization (WHO) expects that figure to nearly double by 2050.
Hearing loss types differ according to their causes. The three hearing loss types are sensorineural hearing loss (SNHL), conductive hearing loss, and mixed hearing loss.
The effects of hearing loss go beyond difficulty with hearing, affecting everything from how people interact to financial demands on individuals and society.
Because hearing loss can have such far-reaching effects, individuals experiencing hearing loss should seek medical attention as soon as they notice a problem. While many types of hearing loss are irreversible, healthcare professionals can help those experiencing hearing loss to improve their hearing.
The three hearing loss types
Hearing occurs when sound waves enter the ear, move through the auditory canal — the passageway from the outer ear — and hit the eardrum, causing it to vibrate. Those vibrations pass to the ossicles, three bones in the middle ear, which amplify the vibrations.
Hair-like cells in the cochlea, an organ that spirals in the inner ear, pick up the vibrations, sending them through the auditory nerve, or cochlear nerve, to the brain. Individuals with normally functioning hearing interpret these vibrations as sound.
Problems with this process can cause hearing loss. Interruptions in the process also can cause deafness or profound deafness.
Hearing loss results in the inability to hear at normal hearing thresholds, 25 decibels or better in both ears, according to the WHO. A whisper is 30 decibels. The WHO defines disabling hearing loss as the inability to hear sounds at 40 decibels in the better hearing ear in adults and 30 decibels in the better ear in children.
About a third of people between 65 and 75 in the U.S. experience hearing loss, according to the Mayo Clinic, and about one in two individuals over the age of 75 have hearing loss.
Those struggling with hearing loss may be experiencing any of three hearing loss types: sensorineural hearing loss, conductive hearing loss, or mixed hearing loss.
Sensorineural hearing loss
Sensorineural hearing loss (SNHL) is the result of damage to the inner ear’s structures or auditory nerve. SNHL is the most common type of hearing loss.
Conductive hearing loss
Conductive hearing loss occurs when something prevents sounds from penetrating the outer and middle ear. Medicine or surgery often can treat conductive hearing loss.
Mixed hearing loss
Mixed hearing loss is a rare condition caused by a combination of issues related to SNHL and conductive hearing loss. Sometimes individuals experiencing SNHL later also develop conductive hearing loss issues.
Sensorineural hearing loss
More than 90% of all hearing loss in adults is sensorineural hearing loss, according to Healthline. Some people refer to SNHL as “nerve deafness,” although this term does not account for SNHL issues involving damage to the tiny hairs in the cochlea called stereocilia.
What is sensorineural hearing loss?
Damage to the auditory nerve or the structures of the inner ear can lead to sensorineural hearing loss. The stereocilia convert vibrations from sound into signals for the auditory nerve and brain, and injury to the stereocilia causes SNHL.
SNHL can range from mild hearing loss to profound deafness, depending on the damage to the stereocilia. Exposure to sounds louder than 85 decibels, the equivalent to heavy traffic noise heard from inside a vehicle, can harm the stereocilia.
Causes of sensorineural hearing loss
Nerve damage to the inner ear’s structures — created by loud noises, genetics, or aging — can cause SNHL.
Congenital sensorineural hearing loss
SNHL that is congenital, or present from birth, is one of the most common birth abnormalities. Congenital SNHL affects between one and three babies per 1,000, according to a StatPearls report. Genetics causes about half of congenital hearing loss cases, with environmental factors causing the other half. Infections and a lack of oxygen are among the environmental causes of congenital hearing loss.
Loud noises and sensorineural hearing loss
Even one-time exposure to sounds over 85 decibels — such as gunshots or explosions — can cause SNHL. Hearing loss may not be noticeable until damage occurs to 30% to 50% of the ear’s stereocilia, according to Healthline.
Age and sensorineural hearing loss
Age-related SNHL, known as presbycusis, is one of the most common conditions affecting older adults. Presbycusis typically occurs in both ears, affecting both equally. This type of hearing loss is gradual and often results from changes to the inner ear as a person ages, although other changes related to the ear and brain as well as certain medical conditions and medicines can be a factor.
Additional causes of sensorineural hearing loss
- Head trauma
- Ménière’s disease, an inner ear disorder
- Otosclerosis, abnormalities that develop in bone tissue
- Lyme disease, a disease often transmitted through tick bites
Symptoms of sensorineural hearing loss
Sensorineural hearing loss can occur in one or both ears, depending on the cause. The hearing loss may develop gradually or suddenly, within several days.
- Bilateral sensorineural hearing loss — Occurring in both ears, this type of SNHL can be the result of genetics, exposure to loud sounds, and diseases such as measles.
- Unilateral sensorineural hearing loss — This type of SNHL, which affects both ears, can be the result of a tumor, Ménière’s disease, or a sudden loud noise in one ear.
- Asymmetrical sensorineural hearing loss — Asymmetrical SNHL occurs in both ears, but with one side experiencing more hearing loss than the other.
Signs of sudden sensorineural hearing loss
Individuals with sudden SNHL often notice symptoms upon waking. The symptoms of sudden SNHL include the following:
- Trouble hearing sounds when there’s background noise
- Difficulty understanding children’s and female voices
- Dizziness or balance problems
- Trouble hearing high-pitched sounds
- Sounds and voices sound muffled
- Hearing voices but not understanding them
- Tinnitus, or ringing in the ears
Conductive hearing loss
Conductive hearing loss is related to problems with the ear canal, eardrum, or middle ear and its tiny bones — the malleus (“hammer”), incus (“anvil”), and stapes (“stirrup”). These issues interfere with the conduction of sound from the external and middle ear to the inner ear.
What is conductive hearing loss?
Conductive hearing loss differs from SNHL in that, instead of occurring in the inner ear, the hearing loss is caused by sound blockages in the outer and middle ear. The blockages may make it difficult to hear soft sounds and may muffle loud sounds.
The hearing loss can be unilateral, in one ear, or bilateral, in both ears.
Causes of conductive hearing loss
A variety of issues can cause conductive hearing loss, including:
- Ear infections
- Fluid in the middle ear, likely from colds or allergies
- Glue ear, from fluids filling the middle ear so the eardrum cannot move
- Poor function of the eustachian tube, which controls pressure in the middle ear
- A hole in the eardrum
- Benign tumors
- Earwax stuck in the ear canal
- Infections in the ear canal, sometimes called swimmer’s ear
- An object stuck in the outer ear
- Incorrect formation of the outer or middle ear
Ear infections can leave scar tissue, which can affect how the eardrum works. Infection and trauma can cause malfunction of the ossicles in the middle ear. Additionally, a condition called ankylosis can cause hearing loss by fusing the ossicles.
Symptoms of conductive hearing loss
Conductive hearing loss typically affects how an individual perceives loudness rather than clarity. Among the symptoms that suggest this type of hearing loss are the following:
- Sensing one’s own voice sounds different
- Difficulty hearing speech
- Conversations sound muffled
- Strange odor from the ear
- Pain or pressure in one or both ears
- Ear discharge
Mixed hearing loss
Mixed hearing loss occurs due to a combination of conductive damage in the outer or middle ear and sensorineural damage in the inner ear. The condition is the result of the sensorineural hearing loss and conductive hearing loss types happening simultaneously.
What is mixed hearing loss?
With mixed hearing loss, individuals experience difficulty conducting sound to the inner ear and brain and also have damage to the cochlea or auditory nerve. The American Speech-Language-Hearing Association gives the following example of mixed hearing loss: An individual experiencing hearing loss because of loud noises (SNHL) as well as hearing loss due to fluid in the middle ear (conductive hearing loss) would have mixed hearing loss.
Causes of mixed hearing loss
Anything that can lead to sensorineural hearing loss or conductive hearing loss can cause mixed hearing loss. The following is an overview of potential SNHL causes:
- Genetic issues
- Head trauma
- Inner ear malformation
The following summarizes some causes of conductive hearing loss:
- Earwax buildup
- Fluids in the middle ear
- Ear infections
- Perforated eardrum
- Outer or middle ear deformity
Long-term ear infections can cause both sensorineural and conductive damage, because they can harm both the eardrum and the ossicles.
Symptoms of mixed hearing loss
The symptoms of mixed hearing loss mirror those of sensorineural hearing loss and conductive hearing loss. Individuals experiencing mixed hearing loss may have difficulty hearing sounds, and those sounds also may be muffled.
Effects of hearing loss and how it impacts daily life
Hearing loss affects more than an individual’s ability to hear. The effects of hearing loss are functional, social and emotional, and economic.
Functional effects of hearing loss
The functional effects of hearing loss extend to an individual’s ability to learn and work.
Inability to communicate
Hearing loss creates challenges for people as they attempt to communicate with others. This difficulty with communicating can create obstacles to developing and maintaining personal and professional relationships.
Difficulty with learning and working
Because communication plays a key role in learning and working, hearing loss can create problems in those areas. Hearing loss — which can make hearing and using sounds like “s,” “sh,” “l,” and “k” difficult — can lead to effects ranging from hampering academic achievement to disrupting vocational choices.
Increased need for assistance
Students and employees experiencing hearing loss may struggle to get the assistance required to address their challenges. The accommodations required to help ensure success for those with hearing loss are not always available. Assistive devices for hearing loss include tools such as captioning, telephone amplifiers, and flashing and vibrating alarms.
Decline in cognitive function
Hearing loss can lead to a lack of stimulation in the senses that affects the brain’s health. Left untreated, hearing loss can increase the risk of dementia as individuals age.
Stress-related stomach pain
The stress related to hearing loss-related challenges can lead to stomach pain and other health issues. Without treatment, hearing loss can cause stress-induced symptoms such as cramps, pain, diarrhea, and constipation or even longer-term issues such as irritable bowel syndrome (IBS).
Loss of balance
Hearing loss and balance problems are symptoms of ear diseases such as Ménière’s disease. Additionally, hearing loss decreases awareness of one’s surroundings and also can affect brain function for tasks including maintaining posture — which can increase the risk of falls.
Social and emotional effects of hearing loss
Hearing loss has social and emotional effects as well. Difficulty communicating with others can lead to feelings such as:
Hearing loss, particularly when it is chronic, can be linked to anxiety disorders, postpartum depression, and mood and seasonal affective disorders.
Economic effects of hearing loss
The WHO estimates that economic effects of hearing loss total $750 billion annually. Among the costs associated with hearing loss are:
- Healthcare, including hearing devices
- Educational support
- Lost productivity
- Societal costs, including lower-quality education and greater unemployment
The lack of educational support is especially pronounced in developing countries, where children with hearing loss often receive no schooling. Lower-quality education, or no education at all, leads to greater unemployment and underemployment.
Gradual and sudden hearing loss treatments
The negative impacts of both gradual and sudden hearing loss make seeking treatment important. People experiencing hearing loss should contact a healthcare professional for diagnosis and treatment.
Diagnosing gradual and sudden hearing loss
Medical professionals may perform a number of tests to diagnose hearing loss. Among the diagnostic procedures the Mayo Clinic lists are the following:
A physician may check the ear for potential causes of hearing loss, including earwax or inflammation. The exam also evaluates possible structural problems.
Although not as accurate as some other tests, whisper tests are another hearing loss screening option. The test requires the patient to cover one ear at a time to check hearing of sounds at different volumes. Hearing loss screening procedures also could include balance tests, an MRI, or a blood test.
Mobile application tests
Mobile apps such as the World Health Organization’s hearWHO tool allow individuals to test themselves for hearing loss.
Tuning fork tests
Tuning fork tests use two-pronged metal instruments that make sounds when someone strikes them. These tests can help diagnose not only hearing loss but its cause in the ear.
Audiologists, medical professionals who diagnose and treat hearing and balance conditions, may conduct audiometer tests. During the test, the audiologist places earphones on a patient to evaluate whether the individual can hear sounds and words in each ear.
Treating gradual and sudden hearing loss
Gradual and sudden hearing loss treatments range from medical approaches to changes in lifestyle.
Removing wax blockage
Medical professionals can remove earwax with suction. They also can use a tool that removes the wax with a loop.
Surgery can treat eardrum and bone malformations. In cases of multiple ear infections, the physician may insert tubes to drain fluid from the ears.
Hearing aids can treat hearing loss caused by inner ear damage. An audiologist can provide information about this option and different styles of hearing aids. Open-fit hearing aids, for example, open the ear canal to allow low-frequency sounds to enter the ear as usual and high-frequency sounds to be amplified.
Severe hearing loss may call for cochlear implants, electrodes that stimulate the hearing nerve. Audiologists and ear, nose, and throat (ENT) specialists provide information about risks and benefits of this approach.
The most common sudden hearing loss treatment is corticosteroids. Corticosteroids reduce swelling and fight inflammation. Physicians often prescribe corticosteroid pills or give shots directly to the ear.
Antibiotic or antifungal treatment
Some underlying causes of hearing loss, such as ear infections, may be treatable with antibiotic or antifungal medication.
Infants and children can receive early intervention through the Individuals with Disabilities Education Act (IDEA). This federal legislation calls for assistance that can aid development of speech, language, and social skills in children under the age of 3.
Hearing loss resources
Those experiencing hearing loss — or caring for someone who is — can turn to these resources for information and support.
- AG Bell works around the world to provide support, information, and resources to help people with hearing loss hear and speak.
- The Association of Late-Deafened Adults (ALDA) is a resource center for information, referrals, help, and support groups for individuals who became deaf or began experiencing hearing loss as adults.
- Hearing Loss Association of America (HLAA) represents individuals with hearing loss, offering programs and events to help them live successfully.
Explore hearing loss types and treatments
The prevalence of hearing loss does not lessen its potential severity or its many negative effects, so seeking medical attention quickly is crucial. Learning the details about the types of hearing loss — sensorineural hearing loss, conductive hearing loss, and mixed hearing loss — and their treatment can help identify potential issues before they lead to more serious consequences.