THE EARS SPEAK TO BE HEARD: HEARING LOSS SIGNS, CAUSES AND TREATMENT

There is little in life more frustrating than losing the ability to hear. Temporary hearing loss is bound to occur at some point in every person’s life. It was estimated that one in every five people suffered from hearing loss in 2019, totaling up to 1.57 billion of the planet’s population.^[1]

As aging is the number one risk factor for hearing loss, it’s important for everyone to take care of their ears. The following article describes how hearing works, signs to watch out for, types of hearing loss, available treatment options and best practices for optimal hearing.

How Does the Ear Hear?

The human ear is a vital organ, responsible for maintaining both hearing and balance. When sound waves are present in the environment, the ears convert sound waves into electrochemical impulses through a process known as transduction.^[2]

The ear is divided into three segments:

• The outer ear is more or less visible and extends inwards towards the tympanic membrane, which demarcates the start of the middle ear. Sound waves are converted into tympanic vibrations after traveling through the outer ear to the inner ear. Ear wax is produced in the outer ear to prevent external material from entering. Occasionally this may reduce hearing capacity.
• The middle ear consists of an air-filled chamber that is divided into two by the tympanic membrane or ear drum. Inside the middle ear, three very small bones reside which transmit vibrations to the inner ear. This chamber is also connected to the nose and throat through the Eustachian tube, which prevents pressure buildup in the ear.
• The inner ear contains the cochlea. The word is a Greek derivative for snail shell, which is precisely what the cochlea resembles. The cochlea is responsible for converting sound waves into electrical impulses that are then sent to the brain via the vestibulocochlear nerve. The cochlea contains thousands of ear “hairs” that move in response to sound vibrations^[3], transforming sound waves into hydraulic energy.

Hearing Loss Signs

Sometimes it can be difficult to distinguish between hearing loss, depression and cognitive decline.

Classic signs of hearing loss include:

• Needing to use a higher than usual volume setting in order to hear
• Frustration when socializing
• Difficulty with language comprehension
• Confusion in a noisy environment
• Depression

Hearing loss is often mistaken in the elderly for cognitive decline. Recent research has shown that the two may be connected, however a patient with hearing loss should never be treated for cognitive decline without a comprehensive assessment.

Types of Hearing Loss

Hearing loss can occur when any part of the ear involved in sound transduction begins to malfunction. It may also occur as a result or potential cause of cognitive decline, where auditory processing in the brain is affected.^[4]

There are two main types of hearing loss: conductive and sensorineural. Those with hearing loss may present with either or a combination of both.

Conductive

Conductive hearing loss pertains to loss of function of ear components which facilitate sound transmission to the inner ear. It can include having compaction in the outer ear, perforation of the eardrum or issues that prevent the bones in the middle ear from functioning properly. This type of hearing loss is not as common as sensorineural hearing loss in the elderly, typically affecting young people more on average.

Common types of conductive hearing loss include:

• Infection. Prolonged ear infections can cause conductive hearing loss in several ways, namely by increasing inflammation and swelling in any part of the ear canal. Ear infections are risk factors for both ossicular misalignment and cholesteatoma (see below).
• Ossicular Misalignment. This occurs when the little bones in the middle ear become misaligned. It is most commonly caused by head injuries.^[5]
• Cholesteatoma. Characterized by a benign cyst-like growth on or near the eardrum. This often forms as a result of chronic infection or repeated eardrum perforation, after which the ear battles to drain subsequent congestion as efficiently. This results in chronic middle ear pressure that pulls the eardrum the wrong way, forming a space in which a cyst forms from dead skin cells.^[6]
• Otosclerosis. This condition refers to a benign bone growth in the middle ear.^[7] Typical manifestations include hearing loss of low tone sounds, tinnitus, speaking very softly and/or hearing one’s voice as louder, worsening of symptoms over time and finding it easier to hear when background noise is present. All these signs contradict classical hearing loss.
• Tympanic Perforation. When the ear drum bursts, it typically results in temporary conductive hearing loss. Common causes include head injury and ear infections.
• Outer Ear Obstruction. Foreign bodies lodged in the ear and compacted ear wax can both result in outer ear obstruction, resulting in conductive hearing loss. Removing the cause of the obstruction typically resolves the problem.
• Surfer’s Ear. Also known as external auditory exostoses, surfer’s ear is caused by a slow progressive benign bone growth in the outer ear which tends to form due to repeated excessive cold water exposure.  Surfers, divers, swimmers, sailors and others who frequently are exposed to cold water are prone to developing surfer’s ear. Unlike otosclerosis, surfer’s ear is often asymptomatic or mildly symptomatic, but may become severe over the course of years. It typically increases the risk of ear infection and ear wax compaction.^[8]

Hearing aids and/or surgical intervention are common treatment options for many of the above types of conductive hearing loss. Infection-induced hearing loss tends to resolve with an appropriate antibiotic treatment.

Sensorineural

Sensorineural hearing loss occurs when there is a neurological problem with auditory processing. The cochlear and vestibulocochlear nerve are generally implicated in this type of hearing loss, however the parts of the brain involved in auditory processing may contribute as well.

Types of sensorineural hearing loss consist of the following:

• Presbycusis. This is merely a fancy term for age-related hearing loss, most commonly affecting elderly individuals with a form of age-related cognitive decline. A hearing aid or cochlear implant are common prescriptions for treating presbycusis.
• Cerebellopontine Angle Tumor or Growth. The cerebellum and the pons are both critically involved in maintaining balance, a function that is shared by the hairs of the inner ear. A tumor or growth in the cerebellum, pons or the area that connects the two (cerebellopontine area) can result in sensorineural hearing loss.
• Autoimmune Inner Ear Disease. This is an autoimmune condition of the inner ear that may be standalone, or caused by a systemic autoimmune disease. Damage to the inner ear creates scar tissue and progressive fibrosis, eventually resulting in cochlea malfunction and deafness. Balance may also be affected by this condition. Corticosteroids are often prescribed for immune suppression; however, they often demand lifetime usage to prevent relapses.^[9] Cochlear implants may help resolve hearing loss in half of those with the condition, whereas the other half may experience more pronounced ear damage as a result.^[10]
• Meniere Disease. An endolymphatic inner ear condition, Meniere disease is characterized by hearing loss, vertigo, and tinnitus. It is believed to be caused by excessive fluid buildup in the ear and nearby lymph glands. Other autoimmune conditions are associated with Meniere Disease and include rheumatoid arthritis, ankylosing spondylitis and systemic lupus erythematosus.^[11]
• Excess Loud Noise Exposure. Acute exposure to a sound above 130dB or chronic exposure to sounds above 85dB can lead to hearing loss or deafness. Acute exposure with sudden hearing loss may resolve within a few hours to a few days.
• Ear Toxin Exposure. Toxins that damage the ear promote hearing loss and dizziness. Chemical pollutants, heavy metals and certain medications are all known to be ototoxic. Medications that may affect hearing by inducing either tinnitus or hearing loss include loop diuretics, NSAIDS, chemotherapy drugs, aminoglycoside antibiotics and quinine antimicrobials (prescribed for malaria and other chronic illnesses). ^[12]
• Injury. Head or neck injuries can also cause sensorineural hearing loss, if a nerve that facilitates hearing is damaged.
• Infection. Ear infections of the inner ear can cause sensorineural hearing loss, particularly when the vestibulocochlear nerve becomes inflamed.

Hearing Loss Risk Factors

Aging is perhaps the number one risk factor for hearing loss, as well as chronic exposure to loud sounds and cold water. Head injury, chronic ear or systemic infections and autoimmune diseases are also risk factors for hearing loss.

Metabolic diseases and those that affect cardiovascular function increase the risk for hearing loss by reducing the function of ear hairs and nerves.^[13]

Other risk factors for hearing loss include:

• Dementia and other neurological conditions that may affect auditory function. All-cause dementia and hearing loss are closely related in the aged population. Some studies have suggested that hearing loss may promote cognitive decline and/or vice versa. The areas of the brain involved in auditory processing very often coincide with those that process speech, language comprehension, and other sensory stimuli.^[14] More research is underway to investigate the relationship between dementia and hearing loss.
• Medications. Antibiotics such as aminoglycosides gentamicin and streptomycin, quinine-based medications including chloroquine, erythromycin, and tetracycline. Painkillers and medications used to break a fever (antipyretics) such as NSAIDs, acetaminophen and salicylates. Chemo drugs such as bleomycin, carboplatin and cisplatin. Other medications that may be ototoxic include phosphodiesterase inhibitors, loop diuretics, hydrocodone, and misoprostol.^[15]

Those being treated for kidney disease, congestive heart failure, malaria and other similar infections, severe tooth decay, and cancer are commonly prescribed some of the above medications.

• Pollutants: Carbon monoxide, tobacco smoke, lead, mercury, tin, nitriles, and solvents such as toluene and trichloroethylene.

Those who work and live in industrial areas are exposed to the above toxins, sometimes in combination with loud repetitive sounds. Builders, repair men, welders, painters, those involved in textiles, farm laborers working with pesticides, and petroleum handlers are at a higher risk for ototoxicity.

Auditory Testing and Diagnostics

Hearing loss may occur as a result of outer, middle or inner ear dysfunction or a combination.

A hearing specialist will employ several diagnostic tests to check for hearing loss, as well as to understand the nature of the problem. A physical examination of the ear will also be taken as well as the patient’s medical history.

Speech Testing

Speech testing generally involves making use of a form of speech to ascertain a patient’s degree of hearing. These tests are often employed before making use of more sophisticated diagnostic tools. Examples include:

• Direct question. The audiologist simply asks the patient if they battle with hearing loss and gauges the response. A patient may even be tested in this manner the moment they walk into the office.
• Finger rub test. The audiologist rubs their fingers together gently near each ear, recording whether the patient can hear it. Hearing loss is suspected if 3 out of 6 attempts go by unnoticed by the patient.
• Whispered voice test. The audiologist stands behind the patient and whispers number or letter combinations a few times in a row. The patient needs to repeat what they hear. Hearing loss is suspected if the patient fails to accurately repeat 3 of 6 attempts.

Tuning Fork Testing

Tuning fork testing involves the use of a tuning fork to ascertain specific aspects of hearing. A tuning fork is a small device that when struck, vibrates and emits a tone of a precise pitch. Two tuning fork tests are commonly employed:

• Rinne Test. The audiologist strikes a tuning fork and places it on the bone behind an ear. The patient then indicates when they no longer hear the sound, which often occurs before the fork has finished vibrating. The fork is then moved parallel to the ear for the patient to hear again. If the patient fails to hear the fork when parallel to the ear, it indicates that they have conductive hearing loss.
• Weber test. A tuning fork is struck and placed in the middle of the patient's forehead. The patient then indicates if they can hear the sound on one or both sides.

Pure Tone Testing

Sometimes referred to as audiometry, pure tone testing makes use of an electronic audiometric device that is able to detect the sensitivity of a person’s hearing. Often such devices resemble headphones. Several tones are produced and the patient signals to the practitioner when they are able to hear the sound. ^[16]

Each tone played back to the patient is at a different pitch and volume to assess whether the patient can hear loud or soft sounds better; as well as what range of frequency can be detected and by which ear. In this way, a physician can accurately assess the hearing capacity of each ear.

Variations of this test are available for children who might struggle to sit still with headphones. A sound booth with speakers on the inside may also be used; however, no distinction can be made between the ears with this type of pure tone testing.

Forms of pure tone testing are available online and through various apps; yet these may not be that accurate as they may be subject to ambient sound interference and distortion.

Tympanometry

This test reveals how well the ear drum works. A small device is placed into each ear that is able to test the eardrums movement. This test can assess whether the eardrum moves too much, too little or not at all. It can also be used to check if the person has a perforation or burst eardrum, an ear infection, earwax compaction or fluid buildup in the middle ear.^[17]

Oto-Acoustic Emission Testing

The ears produce sounds of their own through the movement of ear hairs. These are referred to as oto-acoustic emissions and can be measured with an appropriate audiometic device[1] . Those with tinnitus tend to produce more oto-acoustic emissions on average, while those with hearing loss produce less.^[18]

This type of test is often used to check for hearing abnormalities in newborns. Some audiologists may implement oto-acoustic emissions for checking the condition of the ear hairs in elderly patients who are suspected to have age-related hearing loss. Unlike the other tests above, this is a very accurate way to assess whether the patient has an inner ear problem or not.

Four types of oto-acoustic emission tests are available:

1. Spontaneous. This test checks for spontaneous hair cell emission in the absence of sound.
2. Transiently Evoked. A test for the oto-acoustic response to sounds of a short duration, often clicks or tone bursts.
3. Stimulus-Frequency. Evaluates how well the ear echoes the tone of the sound it hears.^[19]
4. Distortion-Product. Assesses the way the ear responds to two sounds at once.

Transiently evoked emission testing and distortion product emission testing are the two most commonly used by audiologists.^[20]

Auditory Brainstem Response Testing

This test is most often used to check for hearing loss in infants, newborns or those who cannot be tested through conventional audiometry. Electrodes are placed in direct contact with skin on the head while sounds are played back to the patient. The electrodes read brain activity, and are connected to a computer which records the result. The person undergoing this test does not need to be awake during the test, which makes it a lot easier to check for hearing loss, particularly in very young children.

Typically sounds at only one loudness level are checked. If a sound does not register in the brain, more specific diagnostics will be required.^[21]

Treatment Options

• Ear Irrigation

Ear irrigation involves the use of either a special irrigation device or syringe with IV catheter filled with warm water and sometimes an ear wax-softening agent. The water is injected into the ear, loosening the earwax near and on the eardrum. A small container is deployed to catch the water and earwax as it leaves the ear. Sometimes leftover pieces are removed afterwards with special instruments (e.g. cerumen spoon).

There is no known difference between the effectiveness of jet irrigation and syringe irrigation. Making use of a cerumen softening agent improves the success of ear irrigation.^[22]

Contraindications

Those with surfer’s ear, a history of middle or inner ear disease, a burst eardrum or other wound in the ear, or a foreign body in the ear canal should not opt for ear irrigation. Other contraindications include being unable to sit upright or sit still.^[23]

• Hearing Aids

Hearing aids are devices that are fitted onto or into the ear that serve to amplify or enhance faulty aspects of hearing. The basic components of almost all hearing aids consist of a microphone, an amplifier, a receiver and a battery. Together these parts synergistically mimic the way in which the ear receives sound and can be applied to the majority of hearing losses.^[24]

Hearing aids often work hand-in-hand with assistive listening devices which are designed to amplify sound being emitted from the device for the hearing aid to pick up. Specialized headphones, speakers and other electronic devices have been created for this purpose. Some theatre houses have similar technology to help those with hearing aids to better listen to a film.

Over-the-counter hearing aids are available for mild to moderate hearing loss, however they typically work by correcting problems associated with the outer ear. Middle ear and inner ear hearing aids are also available for severe hearing loss, and usually require surgical implantation. 

In spite of their wide availability, it’s important to see an audiologist for a diagnosis and hearing aid prescription.

Contraindications

Hearing aids can lead to needing regular ear irrigation, which is another factor to consider. Those who suffer hearing loss as a result of earwax compaction or infection should not consider hearing aids, as these may increase the problem.

• Ear Surgery

Hearing aids are not always able to resolve hearing loss, in which case surgery may be a viable treatment option. There are many types of ear surgery, with each one able to correct a very niche hearing problem. Examples include^[25]:

• Acoustic neuroma surgery removes tumors of the middle and inner ear in order to improve hearing.
• Cyberknife radiosurgery is a specialized noninvasive surgical technique that uses a high intensity laser “knife” in order to destroy brain tissue that would have otherwise required surgical removal in order to enhance hearing.
• Inner ear reconstruction rebuilds parts of the inner and/or middle ear that didn’t form optimally during fetal development.
• Myringotomy refers to surgery that opens the eardrum in order to drain fluid properly.
• Labyrinthectomy removes diseased parts of the cochlea, known as the labyrinth, which are involved in balance. This surgery improves symptoms of vertigo and enhances balance.
• Ear implant surgery inserts an ear implant, either to improve cochlear or ear bone function.
• Tympanoplasty changes and restores the function of the eardrum or middle ear bones in order to enhance hearing.

Contraindications

Ear surgery is contraindicated where it may worsen a separate condition. For instance, tympanoplasty is not suitable for someone who is suffering from an ear growth. Many forms of ear surgery are also not recommended for children, the elderly, those with ear infections, and those who cannot drain their ears properly (with the exception of myringotomy).^[26]

An otolaryngologist is able to ascertain whether surgery is the best route to take or not as well as which type is best for enhancing hearing.

• Auditory Rehabilitation

Some patients and their families require auditory rehabilitation in order to adjust to living with a hearing aid or hearing loss. This healthcare service is offered by either a certified audiologist or speech language pathologist.^[27]

Generally auditory rehabilitation consists of a wide array of strategies to suit the patient’s needs. Learning sign language, better hearing-oriented communication skills and ways in which to improve hearing capacity (e.g. reducing ambient interference) are common ways to help improve the quality of life for those with hearing loss.

Best Practices for Hearing Preservation

The following tips are the best known ways in which to preserve the ability to hear.

1. Avoid Loud Sound Exposure

Avoiding exposure to loud sounds is one of the best ways to keep one’s hearing intact.

Loud sounds are those that hurt, cause ringing in the ears, force one to raise their voice to be heard above them, or that prevent one from hearing others speak. These promote middle and inner ear damage, yet they’re not always easy to avoid.

Once-off exposure to a sound over 130 dB is enough to cause permanent ear damage, and frequent or continuous exposure to sounds over 85dB can cause eventual hearing loss.

Everyday sounds can be loud enough to promote hearing loss^[28]:

• Road traffic can range anywhere between 70 and 90 dB, while an airplane taking off may be as loud as 120dB.
• Music on full blast can range between 100 and 110 dB, while it may pass the danger threshold (130dB) at live performances and massive parties.

If you work in an occupation where you’re exposed to loud sounds such as heavy machinery, consider getting a form of ear protection to muffle out the sound. Hearing loss may also affect balance and serve as a risk for accidental injury. It may be beneficial to speak to an employer about using quieter equipment where possible.

2. Take Care When Listening to Music

Headphones and earphones are some of the most problematic devices for hearing, and precautions should be met in order to preserve the ears.

The volume should only be loud enough for comfortable listening. Noise-cancelling earphones or headphones can help to improve one’s ability to listen to music without needing to turn the volume up too much in order to block out external sounds.

Using headphones or earphones for longer than an hour at a time may be damaging and those who are required to do so for prolonged periods of time should take breaks in between of 5 mins or more.

3. Focus on Leading a Healthy Lifestyle

There is a small body of research that advocates both a healthy diet and lifestyle for hearing loss prevention. Infections, diabetes, heart disease, obesity, smoking, pollutants, and chemicals are all implicated in promoting age-related hearing loss, for which the risk can be largely reduced by emphasizing health and well-being.

Lifelong physical activity levels have been shown to have a profound impact on hearing ability later on in life^[29]. Regular exercise in mice studies proved to be protective of the ear hairs and vestibulocochlear nerve. These studies also provided genetic confirmation that physical activity promotes optimal ear function by enhancing immune function and lowering infection risk^[30].

Consuming a balanced diet rich in whole fruits and vegetables may help to prevent hearing loss^[31], especially as it is associated with enhanced immune function and improved quality of life as one ages. A nutrient-dense diet has been proven to lower inflammation intensity, to preserve the health of the cardiovascular system and may help to enhance nervous system function. This is suspected to be beneficial for the ears by facilitating optimal cochlear blood flow and reduce the risk of auditory nerve dysfunction.

A study conducted on adults over the age of 50 revealed that consuming a heart-healthy Mediterranean diet may protect against age-related hearing loss, however it did not protect against low frequency hearing loss in aged men.^[32]

Potassium, zinc, magnesium, selenium, iodine, and nearly all vitamins (especially B9) have been linked with promoting optimal hearing^[33]. Additionally, a diet high in protein has been shown to protect the ears. By contrast, malnourishment is associated with impaired ear and hearing development in children.^[34]

When to see a hearing specialist?

It’s important to see a hearing specialist or audiologist when difficulty with hearing is suspected. This is especially true in the case of sudden hearing loss or hearing loss in the absence of a known cause such as infection.

It can be difficult to know if you have hearing loss or not, as symptoms may only present in certain situations or be non-obvious. If you think you may be suffering from hearing loss, hearing loss questionnaires exist online that can help you to assess if you should seek the help of a specialist or not.

Mya Care can help you to connect with an audiologist, otolaryngologist and other healthcare professionals that can help to treat hearing loss.

Conclusion

No one is exempt from suffering temporary hearing loss from time to time. Hearing loss may be of a mechanical (conductive) or neurological (sensorineural) nature, with aging having the greatest association with all-cause hearing loss. Disease, excess exposure to loud sounds, ear toxins, various medications and malnourishment are all major contributing factors. Current treatment options include hearing aids, irrigation, surgery and auditory rehabilitation.

Hearing loss prevention is more than possible if one safeguards their well-being and takes care to manage loud sound exposure. Consuming a well-balanced diet, regularly exercising, treating infections properly and moderating the ambient volume can all help to keep the ears healthy.

If hearing loss is suspected, one needs to seek out an audiologist or otolaryngologist as soon as possible.

To search for the best Ear Nose And Throat (ENT) healthcare providers in Germany, India, Malaysia, Spain, Thailand, Turkey, the UAE, the UK and the USA, please use the Mya Care search engine. 

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