Conductive hearing loss

Conductive hearing loss primarily affects your ability to be able to perceive the loudness of sounds, however, it doesn’t generally affect the clarity. If you have conductive hearing loss, then you may have some or all of these symptoms:

• Your voice sounds different to you
• It’s harder to hear out of one ear than the other
• A strange odour emanating from your ears
• Feeling of pressure in one or both ears
• Normal day-to-day sounds seem softer
• Struggle to follow conversations, particularly on the phone
• Ringing in the ears (tinnitus)

Symptoms of conductive hearing can vary depending on which part of the ear is affected. You may find that you have to turn the volume up on the TV to help you hear the audio better.

There are several different potential causes of conductive hearing loss, these may affect just one part of the ear or several. The underlying cause of conductive hearing loss is often used to classified by the affected part of the ear – the outer ear, ear canal or middle ear. Some of these causes include:

• Impacted earwax (cerumen): This is a common cause of temporary conductive hearing loss and is when there has been a build-up of wax in the ear. It’s frequently made worse by people attempting to clear out the wax themselves with a cotton swab. Excess wax can stop sound from being able to travel to your inner ear.

• Infection of the outer ear (otitis externa): This is an infection of the skin of the external ear canal and can lead to conductive hearing loss when the canal becomes blocked by debris and swelling.
• Squamous cell carcinoma: Most cases of squamous cell carcinomas of the temporal bone are seen in people in their 50s and 60s. It is the most common type of cancer of the external ear canal and along with bleeding, earache and discharge it can also cause conductive hearing loss.
• Blocked Eustachian tube: The Eustachian tube links the back of your nose to the middle ear. It can become blocked when the tube doesn’t open or close correctly or the mucosal tube lining becomes swollen. This can also be a common side effect of flying on an aeroplane when you have a head cold or swimmer’s ear (fluid in the ear).
  
• Eardrum perforation: Trauma in the ear or an infection create a hole in the eardrum. This leads to reduced hearing in the affected ear. This can happen when you insert something too deep into your ear such as a cotton swab, are exposed to very loud noises (known as noise-induced hearing loss) experience head trauma or a blow to the ear. Changes in air pressure (barotrauma) often during an aeroplane flight or scuba diving can also cause a perforated eardrum.
  
• Infection (otitis media): Many types of infection and inflammation can lead to conductive hearing loss such as chronic suppurative otitis media. Otitis media with effusion (fluid in the middle ear) is most frequently associated with tinnitus (ringing in the ears), earache, vertigo and hearing loss. Otitis media is more common in adults who have a lower immune system.
• Otosclerosis: This is a rare, abnormal growth of one of the tiny bones of the middle ear (stapes bone) and stops the structures in the ear from functioning correctly. The causes are usually inflammatory, such as the measles virus and autoimmune processes, hormonal, metabolic and genetic. It’s twice as common in women, particularly those aged between 15 and 40.
• Cholesteatoma: Generally associated with ear infections, these abnormal, non-cancerous skin growths develop behind the eardrum in your middle ear. They often develop as a cyst or sac, and as it increases in size, it can damage the delicate bones of your middle ear.
  
• Paraganglioma: This is the most common primary neoplasm of the middle ear, and the second most common tumour of the temporal bone. It most often affects women in their 50s and 60s. It can cause a sensation of ringing in the ears, while the mass in the middle ear stops sound waves from passing through the middle ear to your eardrum, leading to conductive hearing loss.
• Temporal bone trauma: Blunt head injuries can cause damage to the middle ear and eardrum, while also injuring the inner ear, facial nerves and brain, resulting in hearing loss.

There are several ways that conductive hearing loss can be detected and diagnosed by your doctor. These include:

• Otoscopy: The doctor will insert an otoscope in your ear to look at your eardrum and ear canal. This will show if you have an injured eardrum, foreign body in your ear canal such as impacted earwax or whether there is a problem in the middle ear. The doctor will also examine the colour, translucency and position – to see whether it’s normal, bulging or retracted.
• Weber test: A tuning fork is struck and placed on your head. You’ll be asked to indicate when you can hear the sounds and if the sound is louder in your right ear, left ear, or the middle. If you have normal hearing, the sound should be the same in both ears. If you have conductive hearing loss in just one ear, you will hear the sound louder in that ear.
• Tympanometry: A device similar to a probe is inserted in your ear to check for abnormal pressure, fluid or if you have a growth in the middle ear. They’ll also be able to detect if there is any scarring or perforation to your eardrum. The test is very brief but you’ll have to sit perfectly still during it.
• Pure-tone audiometry: This test is used to assess hearing thresholds to determine if your hearing levels fall within normal limits.

While sensorineural hearing loss is usually permanent, conductive hearing loss tends to only be temporary and resolve itself. It can also be corrected medically or surgically. The treatment for conductive hearing loss will depend on the underlying cause.

• Impacted earwax: Warm-water irrigation is a safe method for removal if there is no history of infection, perforation of the eardrum, or prior ear surgery and if it’s performed by a medical professional.
  
• Infection of the outer ear: The ear canal is debrided, followed by application of ear drops. If the infection is severe, a wick is placed in the ear for two to three days to ensure delivery of the medication. Also, oral antibiotics may be helpful if the infection is severe. Hearing loss typically resolves after the inflammation lessens.
  
• Eardrum perforation: In most cases, the hole heals on its own as long as the ear canal is kept dry. If the ear becomes infected, antibiotic ear drops or oral medication will be prescribed. If the eardrum doesn’t heal within two months, tympanoplasty may be required. This surgery involves using different types of grafts to repair the perforation. A 2015 study showed an 86.6% success rate, following this procedure.

• Infection: Myringotomy is used to release middle ear fluid, enabling sound waves to reach your inner ear. A small incision is made through the layers of your eardrum. The fluid is suctioned from the middle ear through the incision. Ventilation tubes are often used to let the cut eardrum remain open, to allow better drainage of the fluid.