Hearing Loss - Conductive

Three Types of Hearing Loss

• Conductive hearing loss - when hearing loss is due to problems with the ear canal, ear drum, or middle ear and its little bones (the malleus, incus, and stapes).
• Sensorineural hearing loss (SNHL) - when hearing loss is due to problems of the inner ear, also known as nerve-related hearing loss.
• Mixed hearing loss - refers to a combination of conductive and sensorineural hearing loss. This means that there may be damage in the outer or middle ear and in the inner ear (cochlea) or auditory nerve.
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Conductive Hearing Loss
Causes:

• Malformation of outer ear, ear canal, or middle ear structures
• Fluid in the middle ear from colds
• Ear infection (otitis media - an infection of the middle ear in which an accumulation of fluid may interfere with the movement of the eardrum and ossicles
• Allergies
• Poor Eustachian tube function
• Perforated eardrum
• Benign tumors
• Impacted earwax
• Infection in the ear canal
• Foreign body in the ear
• Otosclerosis

Treatments of Conductive Hearing Loss:

Types of conductive hearing loss include congenital absence of ear canal or failure of the ear canal to be open at birth, congenital absence, malformation, or dysfunction of the middle ear structures, all of which may possibly be surgically corrected. If these are not amenable to successful surgical correction, then the hearing alternatively may be improved with amplification with a bone conduction hearing aid, or a surgically implanted, osseointegrated device (for example, the Baha or Ponto System), or a conventional hearing aid, depending on the status of the hearing nerve.

Other causes of conductive hearing loss are: infection; tumors; middle ear fluid from infection or Eustachian tube dysfunction; foreign body; and trauma (as in a skull fracture). Acute infections are usually treated with antibiotic or antifungal medications. Chronic ear infections, chronic middle fluid, and tumors usually require surgery. If there is no response to initial medical therapy, infectious middle ear fluid is usually treated with antibiotics -- while chronic non-infectious middle ear fluid is treated with surgery (or pressure equalizing tubes).

Conductive hearing loss from head trauma is frequently amenable to surgical repair of the damaged middle ear structures, performed after the patient’s general medical status is stabilized following acute traumatic injuries.

A genetic form of conductive hearing loss is otosclerosis, in which there is bony fixation of the stapes (the third little bone of hearing in the middle ear), where sound can’t get to the middle ear. Otosclerosis usually presents with hearing loss in early adulthood. Otosclerosis can successfully be managed with surgery to replace the immobile stapes with a mobile stapes prosthesis or with a hearing aid. Research suggests that the measles virus may contribute to stapes fixation in those with a genetic predisposition to otosclerosis. The incidence of otosclerosis may be decreasing in some communities due to measles vaccination. Otosclerosis (a hereditary disorder in which a bony growth forms around a small bone in the middle ear, preventing it from vibrating when stimulated by sound) usually causes a conductive hearing loss, a hearing loss caused by a problem in the outer or middle ear. Less frequently, otosclerosis may cause a sensorineural hearing loss (damaged sensory cells and/or nerve fibers of the inner ear), as well as a conductive hearing loss.