Conductive Hearing Loss
What is conductive hearing loss?
Sound normally travels down the ear canal to vibrate the ear drum (tympanic membrane). The ear drum is connected to three middle ear bones (malleus, incus, and stapes), which transmit the sound into the inner ear (cochlea). The cochlea is the organ that changes sound vibrations into a nerve signal that goes to the brain.
Conductive hearing loss occurs when sound cannot effectively reach the inner ear, due to problems in the ear canal, ear drum, or middle ear.
What are causes of conductive hearing loss?
Many different things can cause conductive hearing loss. Here are a few:
- Issues affecting the External Ear
- Ear canal infection (otitis externa, swimmer's ear)
- Impacted ear wax
- Foreign objects in the ear canal
- Exostoses (surfer's ear)
- Tumors of the ear canal
- Malformation since birth
- Issues affecting the Middle Ear
How is it evaluated?
Patients with hearing loss are first evaluated with a hearing test and an office exam. Tympanometry, which is a measure of the pressure on the inside of the eardrum, is often also performed at the same time as the hearing test. In some cases a doctor will order a CT scan depending on the findings of the physical exam.