When you consider the fact that researchers have identified more than 400 genetic syndromes linked to hearing loss, it’s kind of mindboggling. Like so many other conditions and diseases, your genes and family heritage can play a role in hearing loss. Hearing genes can mutate or ageing can make some of your genes more susceptible to ear damage or deterioration. Genetic hearing loss may affect the inner ear (sensorineural hearing loss), impact the outer or middle ear (conductive hearing loss), or be mild or severe. Some types of genetic hearing loss only affects males, while others impact females. When babies are born with hearing loss, it’s referred to as congenital. When you develop genetic hearing loss later in life, it may be called adult-onset or progressive, since your hearing gets worse with age.

Hearing impairment caused by disorders is called syndromic hearing loss. This is typically related to malformations of your external ear, along with the presence of additional malformations in other organs or organ systems. If you have no visible deformities of your outer ear or any related medical conditions, this is called non-syndromic hearing loss. Problems in your middle or inner ear are a likely cause of non-syndromic hearing loss. Select syndromes linked to genetic hearing loss:

1. Alport syndrome
2. Branchiootorenal syndrome
3. Jervel and Lange Nielsen syndrome
4. Mohr-Tranebjaerg syndrome
5. Neurofibromatosis 2
6. Pendred syndrome
7. Refsum disease
8. Stickler syndrome
9. Usher syndrome (all three types)
10. Waardenburg syndrome

Advancements in genomics have helped identify more than 6,000 causative variants in more than 150 genes responsible for hearing loss. While thousands of gene therapy clinical studies have been conducted, the risk of serious side effects has hampered its current application for hearing loss. 

Noise-induced hearing loss (NIHL) is caused by overexposure to loud noise, from your work environment or leisure activities you enjoy. About 9% of all adult-onset hearing loss is thought to be caused by occupational noise. While noise is usually defined as an unpleasant sound, even beautifully melodic music may lead to NIHL if it is loud enough. If your occupation involves operating loud machinery or you go to loud sporting events or rock concerts, you could develop related hearing problems.

And speaking of music, occupational exposure to loud music is a problem for some living legends. Who guitarist Pete Townsend is nearly deaf and the band’s lead singer Roger Daltrey also suffers from hearing loss. And Eric Clapton has said in interviews that his hearing loss is related to cranking up amps during his youth.

Research studies underscore how a career in music can be harmful to hearing. A German study that analyzed the health insurance records of 7 million people from 2004 to 2008 found working musicians were nearly four times more likely to suffer from NIHL than those in any other profession. And an Australian study was even more specific, analyzing the hearing of 144 professional French horn players. Researchers found 11–22% of players showed some degree of NIHL. It seems that French horn players are among the professional orchestra musicians most at risk of developing this type of hearing loss.

1. Ototoxicity
   Ototoxicity refers to medications that have the potential to damage your hearing. Ototoxic medications damage sensory cells located in your inner ear, which can result in hearing loss, tinnitus (ringing in your ears), or balance disorders. This damage may be reversible and temporary, but in some cases, it is irreversible and permanent.
   Due to underreporting of ototoxic events and very few long-term studies, it’s unknown how many people suffer from this type of hearing loss. Of the more than 200 different medications with hearing-related side effects, common culprits include aspirin in very high doses, nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen, aminoglycosides (the most widely prescribed antibiotic), certain chemotherapy drugs, and loop diuretics. 
   
   
2. Chemotherapy
   If you or a loved one have ever been on chemotherapy, you know firsthand that the challenging side effects can take a huge toll, physically and emotionally. Platinum-based chemotherapy (e.g. cisplatin) is known to cause nerve damage/pain and ototoxicity, resulting in tinnitus and hearing loss. According to a 2019 study, a large percentage of patients on chemotherapy (80.4%) reported tinnitus in messages they posted to online patient forums. Hearing loss was common, but only seven patients reported reduced tolerance to sound. Experts believe pre-existing hearing problems increase the risk of chemotherapy-related hearing issues, yet only 28.1% of those who experienced ototoxicity mentioned having prior hearing deficits.
   It’s not surprising that the study found ototoxic effects were associated with a lower quality of life, fear, isolation, and depression. Patients also expressed frustration because they were not adequately warned about these side effects.
   In general, when patients complete chemotherapy, hearing and balance problems may clear up, however, in some cases, medication-related hearing loss is permanent. 

If you’ve ever incurred a traumatic brain injury (TBI), including a concussion, perhaps you experienced hearing issues. Most people with head injuries suffer some temporary cognitive, motor, or sensory issues. Some experience permanent physical, intellectual, or behavioral deficits. Trauma-related damage can cause conductive and sensorineural hearing loss, central auditory processing problems, balance issues, and tinnitus.

The most extensive research on this topic has been conducted on veterans with warfare-related head trauma. A retrospective review of 250 veterans with mild TBI found 87% experienced some degree of hearing loss. Blast injuries caused more hearing issues than other types of TBI.

When your head is subjected to a sudden and violent blow, this can cause a complex mixture of diffuse and focal lesions in your brain. One of the possible side effects is damage to any point within your auditory pathway. The eardrum, middle ear, and inner ear are the most common sites of peripheral injury because they are in a direct line of the trauma. The hair cells are the most vulnerable elements of your inner ear. When they’re damaged, you may experience sensorineural hearing loss and tinnitus. You’ll likely have difficulty distinguishing between multiple sound sources or understanding conversations if there is background noise.

Most common TBI-Related Hearing-Related Symptoms are:

1. Otalgia (ear pain)
2. Tinnitus
3. Feeling of fullness in the ears
4. Loudness sensitivity
5. Distorted hearing
6. Hearing impairment

Hearing loss may improve at some point post-injury, however, in some cases, it can persist or worsen. The good news is a variety of treatment options can improve the quality of life for people with TBI-related hearing issues.

But what illnesses and diseases cause hearing loss? There are several illnesses and diseases that can cause hearing loss, including specific types of brain tumours, viruses, cholesteatoma, Meniere’s disease, otosclerosis, and Paget’s disease. Although many of these conditions are rare, it’s important to keep in mind that more common and preventable viruses can lead to hearing loss. 

1. Brain tumours.
   The most common type of benign brain tumor that can impact hearing is an acoustic neuroma (also called vestibular schwannoma) because it develops on nerves leading from your inner ear to the brain. While they’re slow-growing, these tumours can cause tinnitus and hearing loss. Other far rarer tumours that can impact hearing include paraganglioma and endolymphatic sac tumours.
   
   
2. Viruses.
   If you become infected with meningitis, mumps, scarlet fever, measles, rubella, herpes simplex 2, HIV, or West Nile, you may experience hearing loss. Ear infections impact one in 10 children with measles, which can lead to permanent hearing loss.
   
   
3. Cholesteatoma.
   A skin growth that occurs in the middle ear behind the eardrum, this condition is usually linked to repeated infections. Over time, a cholesteatoma can increase in size, destroying the delicate surrounding bones of your middle ear. Although rare, hearing loss, dizziness, and facial muscle paralysis can occur as a cholesteatoma grows.
   
   
4. Meniere’s disease.
   This is a chronic, incurable vestibular (inner ear) disorder associated with an abnormally large amount of fluid in your inner ear. If you have this disease, you may experience fluctuating hearing loss or tinnitus that eventually progresses to sudden attacks of vertigo and dizziness. It’s currently unknown what triggers Meniere’s disease. Theories include circulation problems, viral infections, allergies, an autoimmune reaction, migraines, and a genetic connection.
   
   
5. Otosclerosis.
   A rare, abnormal growth of the bone of the middle ear, this disorder is often inherited. The growth prevents sound from passing to your inner ear. If you suffer from this growth, you’ll likely experience conductive hearing loss, however, sensorineural hearing loss is also a possibility.
   
   
6. Paget’s disease.
   This chronic inflammation of the bone primarily affects older adults. Most people (70–90%) don’t have any symptoms. Progressive hearing loss in both ears is the most frequently seen complication of Paget’s disease.