Conductive loss of hearing takes place when the body has trouble conducting sound waves through the ear. It can occur from a problem with any part of the ear-the external, the inner, the middle, or the tympanic membrane. This type of loss can happen alone or along side of sensorineural loss of hearing, which is a problem in how the brain processes sound. To discover the affected part of the ear, a tuning fork is placed against the midline of the forehead. This test, called a Weber test, lets the audiologist know exactly where in the ear the hearing loss is coming from.There are many different causes for conductive hearing loss. Some can be permanent, but many are temporary problems. Each one is treated in a different way.
In the external ear, the most common causes of conductive loss are excess earwax and ear infections. In both cases, the hearing loss is most often temporary. Hearing is often restored once the excess earwax has been removed or an antibiotic has cleared up the ear infection. Some of the less common causes of conductive hearing loss are tumors in the ear canal, a foreign object becoming lodged in the ear, and surfer’s ear (growth of bone in the ear canal, which causes the canal to narrow and close.)Many travelers are familiar with hearing loss that is caused in the tympanic membrane. Different pressures in the external and middle ear can cause a temporary loss of hearing. This normally happens when pressure in the environment changes, like when traveling through a tunnel on a train or changing altitude in an airplane. Temporary conductive loss of hearing can also occur whenever the tympanic membrane has been ruptured or perforated. Tympanic membrane retraction, a condition where part of the tympanic membrane lies deeper in the eardrum than normal, can lead to a more permanent form of conductive hearing loss.The most common reason for conductive hearing loss in the middle ear is fluid in the ear. This fluid can block the Eustachian tube and can be caused by allergies, tumors, or ear infections. This is generally a temporary condition, though it could become permanent if there are repeated ear infections, especially in children. Less common reasons for conductive loss in this part of the ear include middle ear tumors, otosclerosis (presence of an additional small bone in the middle ear), and cholesteatoma (an expanding growth of a skin-like substance inside the ear.) These conditions can be repaired surgically, and most often the loss is temporary.Within the inner ear, the most common reason for conductive hearing loss is severe otosclerosis. The loss is most often reversed after surgically removing or opening the blockage. Much less common is the conductive hearing loss caused by superior canal dehiscence, a condition caused by the thinning or absence of part of the temporal bone. This condition can be surgically repaired by rebuilding the temporal bone, thus restoring the hearing.Conductive hearing loss can be an annoyance to the sufferer. However, it is a rather common condition that is easily treated and is rarely permanent.