A hearing loss caused by damage to the outer or middle ear is known as conductive deafness. Since the inner ear and eighth nerve are unaffected, the patient is hard of hearing only for air-borne sound. He continues to hear quite well in bone-conduction tests. Furthermore, such a patient has little difficulty in understanding speech if it is loud enough. This is in contrast to perceptive or sensorineural deafness, where discrimination is impaired in addition to reduction of bone conduction.
Most conductive hearing losses in children are the sequelae of hypertrophied adenoids, allergies, or middle-ear infections, with resultant pressure disparity, fluid, and adhesions. The eardrums may reveal a fluid level or they may be scarred, retracted, opaque, perforated, or otherwise extensively destroyed. The amount of damage and type of lesion seen in the eardrum is not a reliable indication of the degree of hearing loss present. There may be marked