Conductive Hearing Loss: Causes, Tests and Treatment

01Basics

How sound reaches the inner ear

Sound normally travels down the ear canal, makes the eardrum vibrate and is passed through three tiny bones in the middle ear (the ossicles) to the inner ear, where nerve endings detect it. MedlinePlus explains that conductive hearing loss occurs because of a mechanical problem in the outer or middle ear: sound is not reaching the eardrum, the eardrum is not vibrating in response, or the ossicles are not conducting sound properly.

Sound can also reach the inner ear directly through the bones of the skull. That is the basis of the bone conduction part of a hearing test.

02Types

Conductive, sensorineural and mixed hearing loss

MedlinePlus explains that sensorineural hearing loss occurs when the tiny hair cells that detect sound in the inner ear are injured, diseased, not working or have died, and that this type often cannot be reversed. Its common causes include aging, regular exposure to loud noise, Ménière disease and certain medicines.

The Yorkshire Auditory Implant Service explains how a hearing test separates the types. If hearing is normal through bone conduction but reduced through headphones, the loss is conductive, pointing to a problem in the ear canal, eardrum or middle ear. If hearing is similarly reduced both ways, it is sensorineural, pointing to the inner ear. When both are reduced but with a gap between them, it is called mixed hearing loss.

03Symptoms

Symptoms and one or both ears

The NHS lists common signs of hearing loss: difficulty hearing people clearly, especially in noisy places, asking people to repeat themselves, turning the TV up louder than others need, difficulty on the phone and feeling tired from concentrating while listening. Sometimes someone else notices first.

MedlinePlus adds that a feeling of pressure in the ear is usually due to fluid behind the eardrum, and that ringing in the ears (tinnitus) can accompany hearing loss. The NHS links difficulty hearing in one ear with a feeling of blockage to earwax build-up, but also to ear infections. A blocked feeling is not enough on its own to know the cause; our guide on muffled hearing explains why.

04Causes

Causes in the outer and middle ear

MedlinePlus lists causes of conductive hearing loss, many of which can often be treated:

• build-up of wax in the ear canal
• fluid remaining in the ear after an ear infection
• a foreign object stuck in the ear canal
• a hole in the eardrum
• a scar on the eardrum from repeated infections
• damage to the ossicles behind the eardrum

The NHS adds that a perforated eardrum can cause sudden hearing loss after an ear infection, a very loud noise or a change in air pressure such as flying. MedlinePlus notes that pressure changes, for example from scuba diving, can also injure the ear.

05Urgent

Sudden hearing loss needs prompt assessment

The NHS advises asking for an urgent appointment if you have sudden hearing loss in one or both ears, if your hearing has been getting worse over a few days or weeks, or if you have hearing loss with other symptoms such as earache or discharge. It may not be serious, but it may need to be treated quickly.

MedlinePlus advises contacting a provider for sudden, severe hearing loss or ringing, hearing that is worse in one ear, hearing loss with ear pain, or new headaches, weakness or numbness. Do not assume a sudden change is wax and wait; our guide on sudden hearing loss covers this situation.

06Examination

Examination and medical history

MedlinePlus says the provider will take your medical history and do a physical exam, which includes looking into the ear canal and at the eardrum. The NHS advises not self-diagnosing from symptoms, as there are many possible causes.

If the cause is not something a GP can treat, the NHS says they may refer you to a hearing specialist for further tests.

07Tests

What hearing tests tell you

Each test answers a different question:

• Audiometry measures the type and amount of hearing loss (MedlinePlus).
• Air and bone conduction compare hearing through headphones with hearing through a vibrator behind the ear, to separate conductive, sensorineural and mixed loss (Yorkshire Auditory Implant Service).
• Tympanometry is listed by MedlinePlus among the tests that may be done.
• CT or MRI scans are used if a tumor or fracture is suspected (MedlinePlus).

These tests help the specialist find where the problem lies. They do not tell you on their own which treatment is right, whether it is safe to clean your ears or whether a device is suitable. Useful questions for the audiologist are which type of loss you have, in which ear, how much, and what the likely cause is.

08Treatment

Treatment depends on the cause

The NHS says treatment depends on the cause: an ear infection might be treated with antibiotics and wax build-up with ear drops or removal. MedlinePlus lists surgeries that may help some types of hearing loss: repair of the eardrum, tubes in the eardrums to drain fluid, and repair of the small bones of the middle ear (ossiculoplasty).

Ear cleaning should be guided by a professional who has checked the eardrum. The NHS warns against putting fingers or objects such as cotton buds in your ears, and MedlinePlus advises having a provider remove a foreign object unless it is easy to reach, never with sharp instruments. Our guide on earwax blockage covers wax specifically.

09Sources

Where the sources differ

Wax at home. MedlinePlus says wax can often be flushed out gently with an ear syringe and warm water. The NHS advises against putting objects in the ears and says wax may be treated with drops or removed. Whether flushing is safe depends on the state of the eardrum, so ask a professional first.

Associated symptoms. MedlinePlus lists dizziness among symptoms that can accompany hearing loss, but links it mainly to inner ear conditions such as Ménière disease, not to conductive loss.

Devices. The Yorkshire service explains that bone conduction devices suit some people with conductive or mixed loss; the NHS says hearing aids are often recommended for permanent loss. The choice depends on specialist assessment.

10Summary

In summary

Conductive hearing loss is caused by a mechanical problem in the ear canal, eardrum or middle ear, such as wax, fluid, a foreign object, a perforated or scarred eardrum or damaged ossicles. Many causes can be treated. Comparing air and bone conduction helps tell it apart from sensorineural and mixed loss.

Sudden or worsening hearing loss needs an urgent appointment, and nothing should be put in the ear. Treatment depends on the cause, from drops and antibiotics to surgery, with devices for lasting loss. In our ENT practice in Bilbao we assess hearing loss in adults (consultations are in Spanish).