A Guide to Sensorineural Hearing Loss
Globally, hearing loss affects 1.5 billion people, including those experiencing either sensorineural or conductive hearing loss (or a mix of the two).
If you are one of the 1.5 billion affected by hearing loss or are worried about any new symptoms that have developed, this article is for you. We'll explain sensorineural hearing loss, what causes it, who's at risk, the signs and symptoms, and potential treatment options.
If you're experiencing issues in relation to hearing loss and are local to Suffolk, consider reaching out to Ear View for professional assistance.
What is Sensorineural Deafness?
Sensorineural deafness, also known as sensorineural hearing loss (SHNL), is a type of hearing impairment caused by damage to the cochlea's tiny hair cells or the auditory nerve.
The tiny hair cells in the cochlea convert sound vibrations into electrical signals and transmit them to the brain via the auditory, where the brain interprets the signals as sound. Damage to these cells or the auditory nerve is permanent as the cells cannot regenerate, resulting in permanent hearing loss.
The term ‘sensorineural deafness' dates back to the early 19th century when audiologists began classifying hearing problems based on where in the ear is affected (e.g.outer, middle, inner). The naming reflects the involvement of sensory (cochlea) and neural (auditory nerve) in the hearing impairment.
However, the history of the study of deafness dates back much further to ancient Egypt in 1500BC where early audiologists recorded remedies for the “Ear that hears badly” in Ebers Papyrus.
What causes Sensorineural Hearing Loss?
Sensorineural hearing loss (SNHL) occurs when the inner ear or auditory nerve is damaged, preventing sound signals from being properly transmitted to the brain.
This type of hearing loss is typically permanent and can be caused by a variety of factors, including age, genetics, exposure to loud noises, infections, ototoxic medications, autoimmune disorders, and congenital and developmental issues.
Ageing
Sensorineural Hearing loss can occur due to the body's natural ageing process. Age-related hearing loss (presbycusis) occurs due to gradual degeneration of inner ear structures - such as tiny hair cells and the auditory nerve - resulting in hearing impairment and deafness.
As we age, other changes in the body include vascular changes (reducing blood flow to the ear) and weakened immune responses, which have been linked to presbycusis.
Genetic mutations
Studies have shown that genetic mutations are a major contributor to sensorineural hearing loss, with hereditary factors accounting for a significant number of cases - with 125 genes identified in connection with hearing loss that occurs without other known medical conditions (otherwise known as nonsyndromic hearing loss). In particular, genes such as GJB2 and SLC26A4.
These genes aid in maintaining the ion balance in the cochlea (GJB2) and inner ear (SLC264A), when these genes mutate they may not function correctly and lead to hearing loss.
Exposure to loud noises
Another leading cause of sensorineural hearing loss is prolonged exposure to loud noises. Excessive loud noise exposure can damage the tiny hair cells in the cochlea and induce neurodegenerative changes in the auditory nerve, resulting in permanent hearing loss.
Infections
Cytomegalovirus is related to the herpes virus and can lead to congenital hearing loss in infants and newborns if the mother is infected during pregnancy.
Bacterial meningitis is an infection that causes inflammation of the protective membranes surrounding the spine and brain. If this inflammation spreads to the inner ear, it can harden the cochlea and result in severe and often permanent hearing loss.
Congenital and developmental
Congenital sensorineural hearing loss can occur due to many prenatal factors, such as maternal infections (as mentioned above, herpes virus) and exposure to harmful substances (smoking, alcohol, certain medications).
These factors can disrupt fetal auditory development and potentially result in hearing issues. Additionally, premature birth can increase the likelihood of sensorineural hearing loss due to undeveloped cochlea structures.
Autoimmune disorders
An autoimmune disorder occurs when the body's immune system mistakenly attacks its healthy cells (including those in the ear), incorrectly identifying them as harmful to the body, like bacteria or viruses.
When this occurs in the ear, it is known as autoimmune inner ear disease (AIED) and can lead to hearing loss.
Some autoimmune disorders that affect the ear are: Rheumatoid Arthritis and lupus, which can cause inflammation in the ear and disrupt function; Vasculitis, which can reduce blood flow to the ear; and Multiple Sclerosis, which can cause nerve damage to the auditory nerve.
Who is most at risk of Sensorineural Deafness?
Sensorineural deafness can occur at any age. However, those most at risk are individuals exposed to the risk factors mentioned above, such as ageing, prenatal infections, genetic predisposition, medical conditions, taking ototoxic medication, and prolonged exposure to loud noises.
Age is a major contributor to hearing loss, with over 50% of the population aged over 50 and 80% of the population over 80 experiencing either conductive hearing loss (problems relating to the outer ear which is often treatable), sensorineural hearing loss (relating to the inner ear and usually resulting permanent hearing loss), or a mixture of the two.
Individuals exposed to loud noises, especially in the workplace, are at an increased risk of developing sensorineural deafness. In Great Britain, it is estimated that 12,000 workers experience work-related hearing problems yearly. Age again plays a factor in hearing loss associated with prolonged exposure to loud noises; a study on noise-induced hearing loss found that workers over 40 and above are more susceptible to hearing issues due to loud noise exposure.
Newborns are also at risk of sensorineural deafness due to various factors, such as genetic conditions, prenatal infections, premature birth, or birth complications.
Those with autoimmune disorders are at an increased risk of sensorineural hearing loss, with one study suggesting that up to 50% of patients with autoimmune inner ear disease experience intermittent hearing loss.
The risk of developing sensorineural hearing loss due to ototoxic medication is significant for those taking chemotherapy drugs, with studies showing that these types of drugs have been linked to hearing issues in 40-60% of treated individuals.
What are the signs and symptoms of Sensorineural Hearing Loss if you have it yourself?
Sensorineural deafness can develop over time or come on suddenly.
Common signs include difficulty hearing people, difficulty hearing on the phone, feeling tired or stressed when having to concentrate, and issues with distinguishing words in noisy environments.
Symptoms can include tinnitus (ringing in the ears), problems with balance, dizziness, and high-frequency sounds becoming harder to hear.
What are the signs and symptoms of Sensorineural Hearing Loss in others?
Signs of hearing loss in others can include the individual having the TV or music turned up to what you would deem uncomfortably loud, asking others to repeat themselves multiple times, and having difficulty hearing on the phone or in noisy environments.
Hearing loss in babies can be hard to spot. However, the government has a checklist on what to look for as your baby grows to check their hearing - including their reactivity to sound and interactions.
Is Sensorineural Hearing Loss gradual or sudden?
Sensorineural hearing loss can be gradual or sudden, depending on the underlying cause.
For example, ageing, exposure to loud noises, and medical conditions affecting the inner ear tend to occur gradually and result in permanent hearing loss.
However, sudden sensorineural hearing loss tends to occur rapidly, often due to viral infections, autoimmune responses, and vascular issues.
This type of hearing loss is considered a medical emergency.
Does Sensorineural Deafness affect one or both ears?
Sensorineural deafness can affect one or both ears.
Unilateral (affecting one ear) sensorineural hearing loss is often a result of viral infections, trauma, or noise exposure.
Bilateral (affecting both ears) sensorineural hearing loss is associated with aging, noise exposure, medication, and predisposed genetic conditions.
Is Sensorineural Deafness Permanent, and will it get worse?
Sensorineural deafness is usually permanent, as it results from damage to the inner ear or auditory nerve. Once the damage is done, it cannot be reversed. However, some sudden occurrences of sensorineural hearing loss can occasionally improve if treated promptly.
Is having Sensorineural Deafness a wider health risk?
Some studies suggest that sensorineural deafness can have a wider health risk as those with untreated hearing impairment may experience cognitive declines; as the brain has to work harder to process sound, the risk of dementia developing may be increased.
Sensorineural hearing loss can increase the likelihood of mental health problems as it can increase social isolation due to difficulties in communication, leading to withdrawal of social interactions.
Additionally, as sensorineural hearing loss can cause dizziness and balance problems, it can add to the likelihood of falls which could lead to injury.
How is Sensorineural Deafness diagnosed?
Sensorineural deafness is diagnosed through clinical evaluation and hearing tests.
A GP will physically examine the ear to rule out any potential external causes, such as ear wax build up or middle ear infections.
If no external factors are found, a hearing test will be performed. In some cases, an MRI may be used to identify if any structural abnormalities are affecting the auditory nerve.
What treatments can work for Sensorineural Deafness?
Sensorineural hearing loss is often permanent, but several treatments, such as hearing aids, cochlear implants, assistive listening devices and micro suction ear wax removal can help manage symptoms and improve hearing.
Hearing aids work by amplifying sound and enhancing speech clarity, making communication easier. They are typically suitable for individuals experiencing mild to moderate hearing loss.
Cochlear implants are surgical devices that bypass damaged hair cells and directly stimulate the auditory nerve. They are most suitable for those with severe sensorineural hearing loss.
Assisted listening devices are devices that have been modified to help individuals hear more easily in specific environments, such as amplified telephones.
Micro suction ear wax removal gently removes impacted ear wax. While it is not a direct treatment for sensorineural hearing loss, it can improve overall hearing clarity.
What's the next step if the above treatments don't work?
If treatments aren't working, it's essential to consult with an audiologist to explore alternative treatment options and reassess the severity of symptoms.
If symptoms do not alleviate, more advanced hearing tests, such as a comprehensive hearing assessment or imaging tests (MRI and CT), may be necessary to help identify potential causes.
If symptoms are caused by an underlying health condition, such as an autoimmune disorder or diabetes, ensuring these conditions are managed correctly may help slow progression or avoid further hearing impairment.
If symptoms have started or progressed since taking ototoxic medication, it is important to consult with a doctor; in some cases, it may be possible to look at alternative medicines.
If all treatment options are exhausted or symptoms are severe, exploring lifestyle adjustments and support may be suitable. For example, speech therapy, sign language, or lip reading can help with communication or joining a support group for emotional and well-being support.
In summary…
Sensorineural deafness can significantly impact daily life; understanding its causes and treatments is the first step toward better hearing health.
From genetics to the natural ageing process to exposure to loud noises, the underlying causes for this condition vary greatly - but so do the treatment options.
Whether it's hearing aids, cochlear implants, or a few lifestyle adjustments, there are ways to improve your hearing and communication and maintain your quality of life.
If you are experiencing gradual sensorineural hearing loss symptoms, it is essential to contact a doctor as soon as possible. Remember, any sudden hearing loss is classed as a medical emergency and requires immediate intervention.
An often overlooked factor in hearing health is excessive earwax, which can often exacerbate hearing problems. Micro suction is a safe, effective, and painless method for removing earwax. Removing hard or excessive earwax can improve hearing clarity.
