A common Hearing Loss in Adults

Among the different types of hearing loss, conductive hearing loss

is one that occurs when sound waves are unable to reach the inner ear.

Introduction

Hearing loss is a prevalent condition that affects millions of people worldwide. Estimates of the number of South Africans with disabling hearing loss can vary depending on the source and the specific definitions used. In general, “disabling hearing loss” is defined by the World Health Organization (WHO) as a hearing loss greater than 40 decibels (dB) in the better ear for adults (or greater than 30 dB for children). Based on this definition, it can be stated that no less than 3 to 4 million South Africans live with disabling hearing loss.

Among the different types of hearing loss, conductive hearing loss is one that occurs when sound waves are unable to reach the inner ear. This type of hearing loss can be temporary or permanent and can range from mild to severe. In adults, conductive hearing loss can result from various factors, including ear infections, blockages, and structural abnormalities. This essay will explore the most common causes, symptoms, diagnosis, treatment, and prevention of conductive hearing loss in adults.

Causes of Conductive Hearing Loss

Conductive hearing loss occurs when there is an obstruction or damage in the outer or middle ear that prevents sound from reaching the inner ear. The outer ear is the ear shell, and the ear canal up to the eardrum, the middle ear is between the eardrum and the inner ear (or cochlea). Several factors can cause this type of hearing loss in adults:

  • Ear Infections: Chronic ear infections can lead to inflammation and fluid buildup in the middle ear, which can obstruct sound transmission. In young children this is very common, but it can also occur in adults.
  • Earwax Buildup: Excessive earwax can block the ear canal, preventing sound waves from reaching the eardrum. In order to create a serious, notable conductive hearing loss, an exceptional amount of earwax needs to be present in the ear canal, obstructing all sound waves from reaching the tympanic membrane or immobilizing the tympanic membrane.
  • Eustachian Tube Dysfunction: The Eustachian tube helps equalize pressure in the middle ear. This tube connects the middle ear to the back of the nose. Normally, the Eustachian tube opens with every swallow or yawn to act as a pressure-equalizing valve for the middle ear. It also serves to drain the mucus produced by the lining of the middle ear. Dysfunction of this tube can lead to fluid accumulation and hearing loss.
  • Otosclerosis: Otosclerosis happens when a tiny bone inside the ear, called the stapes, joins (fuses) with other parts of the ear and stops the ability to hear properly. It is an abnormal form of bone growth. It is not entirely known why otosclerosis happens, but it may be passed on in families. One is more likely to get otosclerosis if a close relative has it.
  • Ear Tumors or Cysts: Growths such as cholesteatomas can develop in the ear and block sound waves. Cholesteatoma is an abnormal growth of skin cells in the middle ear behind the eardrum. It can be present from birth (congenital) but typically happens because of chronic ear infections. The most common symptom is a smelly discharge from the ear, but the condition can also cause hearing loss and dizziness. Treatment is surgery to remove the growth; no surgery is usually not an option.
  • Ruptured Eardrum: Trauma, such as from explosions, car accidents, or exposure to extremely loud noises, can cause the eardrum to rupture. Infections can also lead to a ruptured eardrum, resulting in hearing loss. This condition is also called tympanic membrane perforation. It often heals within a few weeks without treatment. However, sometimes a patch or surgical repair is needed to heal.

Symptoms of Conductive Hearing Loss

The symptoms of conductive hearing loss can vary depending on the underlying cause and severity of the condition. Common symptoms include:
  • Muffled Hearing: Sounds may seem faint or muffled, making it difficult to understand speech. Softer sounds are inaudible, and loud sounds are much softer than normal.
  • Ear Pain or Discomfort: Infections or blockages can cause pain or a feeling of fullness in the ear.
  • Balance Issues: Problems with the vestibular system can lead to balance issues. The sense of balance is located in the inner ear and ear problems often lead to phenomena like dizziness.
  • Ear Popping or Ringing: Some individuals may experience a popping or ringing sensation in the ear, or a pulsating noise or tinnitus, synchronous with the pulse.
  • Hearing One’s Own Voice Loudly: This phenomenon, known as autophony, occurs when sound waves are trapped in the ear.

Please note that none of these symptoms are enough to form a diagnosis conclusively, as many of these symptoms can also occur without the presence of a conductive hearing loss. Only a professional evaluation can determine with certainty the presence of a conductive hearing loss.  A conductive hearing loss, impacting hearing to a large degree, can be significantly detrimental to the quality of life of the patient. As in many cases treatment is possible, waiting to seek medical advise is unnecessary and not helpful.

Diagnosis of Hearing Loss

Diagnosis of Conductive Hearing Loss

Diagnosing conductive hearing loss involves a thorough examination by an audiologist or an ear, nose, and throat (ENT) specialist.
Following the initial medical history-taking, the diagnostic process may include:
  • Physical Examination: The doctor will examine the ear canal and eardrum for signs of blockages, infections, or abnormalities.
  • Hearing Tests: Audiometric tests, such as pure-tone audiometry and speech audiometry, can help determine the degree and type of hearing loss. Tympanometry is a test to determine the pressure in the middle ear and the mobility of the eardrum.
  • Imaging Studies: In some cases, imaging studies like CT scans or MRIs may be necessary to identify structural issues in the ear.

Treatment of Conductive Hearing Loss

The treatment for conductive hearing loss depends on the underlying cause. Some common treatment options include:

  • Medications: Antibiotics or antifungal medications can treat infections that cause the conductive hearing loss.
  • Earwax Removal: Professional removal of earwax can restore hearing in cases of blockage.
  • Surgery: Surgical procedures, such as tympanoplasty (restoration of the eardrum) or stapedectomy (restoration of the ossicle chain in the middle ear), can repair structural abnormalities in the ear. Surgery in case of a cholesteatoma is primarily targeting the complete removal of the abnormal growth of skin cells, as any cell left may create over time a new cholesteatoma. Restoring hearing is a secondary objective of surgery in such cases.
  • Hearing Aids: In cases where the conductive hearing loss is permanent or prolonged, hearing aids can amplify sound and improve hearing significantly. In patients whose inner ears are still functioning normally, the usage of hearing aids can result in a significant improvement in hearing.

Prevention of Conductive Hearing Loss

Preventing conductive hearing loss involves taking steps to protect the ears and maintain ear health. Some preventive measures include:

  • Avoiding Loud Noises: Exposure to loud noises can damage the ear and lead to hearing loss. Using ear protection consistently in noisy environments can help prevent this.
  • Maintaining Ear Hygiene: Maintaining good ear hygiene is essential to avoid wax buildup and potential infections. While ears typically have a self-cleaning mechanism, excessive wax can lead to issues such as muffled hearing or dizziness, making professional removal advisable.
  • Seeking Prompt Treatment: Early treatment of ear infections and other ear conditions can prevent complications and hearing loss.

Conclusion

Conductive hearing loss in adults is a condition that can significantly impact an individual’s quality of life. Understanding the causes, symptoms, diagnosis, treatment, and prevention of this type of hearing loss is essential for managing and mitigating its effects. With proper care and timely intervention, many cases of conductive hearing loss can be treated effectively, allowing individuals to maintain their hearing health and overall well-being. If conductive hearing loss is permanent, hearing aids can be a great solution.

For more information on hearing and hearing loss, call your nearest Ear Institute or the Hearing Helpline at 0861-10-20-30

Authors

  • Me Anneke van Wyk – Ear Institute Senior Audiologist
  • Drs. Hans E. Mülder, Physicist, Audiologist