Multiple sclerosis (MS) is a disease that directly impacts the body’s central nervous system (CNS), including the brain, spinal cord, and optic nerves.
Since MS is considered a progressive condition, the wide range of signs and symptoms can slowly impact over time and sometimes be overlooked.
While symptoms like fatigue and mobility issues are ever-present in MS, problems with hearing have also been noted by some with MS.
But how common is it? Can MS cause hearing problems?
A Closer Look at Multiple Sclerosis
According to data by the Multiple Sclerosis Association of America (MSAA), in the United States alone, roughly one million people are living with MS.
The condition is more prevalent among women than men.
While anyone can be diagnosed with MS at any stage, most symptoms first present between the ages of 15 to 50. Currently, there is no known cure for MS.
What Is Multiple Sclerosis?
Multiple sclerosis is a chronic condition that adversely affects the body’s central nervous system.
The central nervous system is composed of the brain and spinal cord.
Most evidence points to MS as an autoimmune disorder — the immune system attacks healthy tissues.
Under normal conditions, the immune system is responsible for protecting our bodies against infection and illness.
The two primary immune system cells responsible for this are white blood cells (WBC) and lymphocytes.
Multiple Sclerosis and the Immune System
MS is considered an immune-mediated disease.
This simply means the body’s immune system attacks the wrong target, in this case, the central nervous system.
In MS, the immune system attacks and damages cells and structures within the central nervous system, specifically:
- Nerve fibers under the myelin
- Oligodendrocytes (myelin-producing cells)
Within these structures of the central nervous system, the immune system generates inflammation that damages myelin (demyelination), an insulating layer (sheath) that forms around the nerves of the brain and spinal cord.
In addition to the damage done to the myelin, the nerve fibers that insulate the myelin and the cells that produce them are also damaged or destroyed.
This immune-mediated condition ultimately causes messages within the central nervous system to be altered or stopped indefinitely.
It is this damage to the central nervous system that causes the wide variety of neurological symptoms that are experienced by those with MS.
This damage causes scar tissues (MS lesions) to develop in the affected areas, where the condition gets the name multiple sclerosis or multiple areas of scarring.
MS patients will experience the condition in one of four disease courses (types of MS): Primary progressive MS, secondary progressive MS, relapsing-remitting MS, or clinically isolated syndrome.
One of the most useful tests to diagnose MS is magnetic resonance imaging (MRI).
What Are the Symptoms of Multiple Sclerosis?
The symptoms of MS can vary widely among people. No two individuals will experience MS in the same way or at the same time.
There is no sure way to predict the extent of symptoms or when they will present themselves.
According to the National Multiple Sclerosis Society, the most common symptoms associated with MS include but are not limited to:
- Fatigue – Occurs in roughly 80 percent of those with MS.
- Trouble walking (gait) – Due to weakness, loss of balance, etc.
- Tingling or numbness – Tingling and numbness is often the first symptom.
- Vision problems – Also among the first symptoms for many with MS.
- Bladder and bowel issues – Bladder dysfunction and constipation.
- Spasticity – Feelings of stiffness in limbs; muscle spasms.
- Pain – Pain syndromes are common among those with MS.
- Depression – Can be a primary symptom or triggered by disease changes.
A Closer Look at Hearing Loss
Hearing loss occurs when your auditory system isn’t functioning as it should, and you lose 30 decibels of hearing or more.
As a medical condition, hearing loss is very common. It affects roughly 15 percent of American adults.
Hearing loss can be unilateral (occurring in one ear) or bilateral (occurring in both ears).
Worldwide, disabling hearing loss affects roughly 430 million people, according to hearing loss data by the World Health Organization.
That number may double by 2050.
Signs and symptoms that are associated with hearing loss include:
- Having to increase the volume on the TV or radio constantly.
- Asking people to repeat themselves over and over again in conversations.
- Problems hearing or discerning speech due to background noise.
- Constant trouble understanding speech in noisy environments.
- Reading lips to understand what people are saying.
- Trouble hearing people speak over the telephone.
- Issues discerning speech from high-pitched voices (e.g. children).
What Is the Auditory System?
Hearing loss occurs when there are disruptions in the auditory system or ear structures.
The most integral parts of the auditory system include the outer, middle, and inner ear and the auditory nerve.
These parts help convert sound waves into electrical signals sent to and processed by the brain.
The outer ear is the visible part of the ear we see (pinna). Its primary job is to gather sound waves and direct them into the ear canals.
The middle ear is composed of air-filled cavities. Here, small bones (ossicles) help send sound vibrations to the inner ear.
The inner ear is a network of semicircular canals, hair cells, and nerves.
Hair cells in the inner ear receive the sound vibrations from the middle ear and help send signals to the brain through the auditory nerve.
It is the damage to these hair cells that contribute to hearing loss.
Is There a Connection Between MS and Hearing Problems?
Problems with hearing are an uncommon symptom of MS. Only six percent of those with MS complain of hearing loss directly associated with MS.
Deafness caused by MS is also extremely rare.
Hearing issues can be extremely multifaceted and can generate from various causes. Hearing loss among people with MS might be due to a non-MS issue.
However, that is not to say there can be no connection between MS and hearing issues.
Some suggest that MS could damage the nerve pathways in the auditory system.
This includes auditory pathways to the brain and brainstem necessary for hearing.
Hearing issues could occur as part of an MS exacerbation or MS relapse.
Simply put, this refers to when MS triggers or worsens old symptoms or new ones arise. So, hearing problems could develop during exacerbation, but these are typically short-term.
MS and Sensorineural Hearing Loss
One of the most common forms of hearing disorders is sensorineural hearing loss (SNHL).
Generally, sensorineural hearing loss is due to normal aging.
This age-related hearing impairment occurs when structures, hair cells, and nerve pathways of the inner and auditory system are damaged or degenerate.
MS can exacerbate these hearing problems and contribute to audiological issues like disruptions in the auditory brainstem response.
Aside from losing hearing due to normal aging, sensorineural hearing loss can also be due to other factors. Here are a few.
- Diseases and illnesses like Ménière’s disease, autoimmune inner ear disease, cochlear otosclerosis, chronic ear infections, and benign tumors can cause SNHL.
- Heredity can make you more susceptible to inner ear deterioration from aging.
- Certain medications or side effects from medication can lead to damage to the inner ear.
- Chronic exposure to loud noises can damage the hair cells and contribute to hearing loss.
In most cases, sensorineural hearing loss is permanent.
However, non-surgical healing devices like hearing aids and surgical intervention like cochlear implants are routinely prescribed as effective treatments.
MS and Sudden Sensorineural Hearing Loss
While sensorineural hearing loss is most often a result of aging, a condition known as sudden sensorineural hearing loss (SSHL) can also occur.
SSHL is also known as sudden deafness. In short, SSHL is an unexplained and rapid hearing loss all at once or over a few days.
SSHL typically only affects one ear. Some experience a loud “pop” when SSHL occurs, while others simply wake up to hearing loss one morning.
According to the National Institute of Health, SSHL affects up to six people per 5,000 yearly.
Some symptoms of SSHL include but are not limited to dizziness, a full feeling in the ear, and tinnitus (ringing in the ear).
Potential causes of SSHL include:
- Infections and autoimmune diseases
- Trauma to the head
- Issues with blood circulation
- Exposures to certain medications
Many believe that SSHL could be sparked by neurology-related disorders like MS.
One systematic review states that SSHL could be an early detector of MS.
Treatments for SSHL include corticosteroids, which can reduce swelling and inflammation.
Regardless of the cause, SSHL is a medical emergency, and you should contact your healthcare provider immediately if it occurs.
MS and Tinnitus
Tinnitus is a common condition causing a “ringing in the ear.”
It can also sound like a buzzing, whistling, clicking, or hissing.
The cause of tinnitus can vary, but the most common include aging, medication side effects, and exposure to loud noises.
Tinnitus is often a sign of early stages of age-related hearing loss.
Tinnitus can also be an otolaryngologic symptom of MS, though research suggests that it only occurs in one percent of cases.
Diagnosing Hearing Loss and MS
The only way to truly diagnose hearing loss is through a hearing test.
Audiologists usually perform these and can diagnose the severity.
A neurologist who treats MS may also be able to spot possible damage to auditory pathways and nerves through MRI scans. But they will most likely refer you to an audiologist or ENT physician for hearing-specific treatments.
Multiple sclerosis is a progressive, immune-mediated condition that adversely affects the body’s central nervous system.
Through inflammation, this disease attacks healthy sheathing that insulates the nerves around the brain and spinal cord.
The signs and symptoms of MS vary from person to person and can be unpredictable. While less common, problems like hearing loss have also been reported with MS.
If hearing loss is a symptom for those with MS, the best course of action is to see a neurologist and audiologist.
These professionals can work together to diagnose and treat hearing loss.