[3] Major causes are ear infections or conditions that block the eustachian tube, such as allergies or tumors.

[4] Third window effect caused by: Conductive hearing loss makes all sounds seem faint or muffled.

For basic screening, a conductive hearing loss can be identified using the Rinne test with a 256 Hz tuning fork.

A type B tympanogram reveals a flat response, due to fluid in the middle ear (otitis media), or an eardrum perforation.

[5] A type C tympanogram indicates negative middle ear pressure, which is commonly seen in eustachian tube dysfunction.

CT scan is useful in cases of congenital conductive hearing loss, chronic suppurative otitis media or cholesteatoma, ossicular damage or discontinuity, otosclerosis and third window dehiscence.

[6] If absence or deformation of ear structures cannot be corrected, or if the patient declines surgery, hearing aids which amplify sounds are a possible treatment option.

These can be on a soft or hard headband or can be inserted surgically, a bone anchored hearing aid, of which there are several types.