Conductive hearing loss
|Conductive hearing loss|
|Anatomy of the human ear.|
Conductive hearing loss is a failure in the efficient conduction of sound waves through the outer ear, tympanic membrane (eardrum) or middle ears (ossicles). This type of hearing loss may occur in conjunction with sensorineural hearing loss or alone.
Causes of conductive hearing loss
Differentiating conductive and sensorineuronal hearing loss
When a Weber test is carried out, sound localizes to the ear affected by the conductive loss. A Rinne test, in which air conduction is normally greater than bone conduction, is usually negative (abnormal), and shows higher greater bone conduction than air conduction.
Table 1. A table comparing sensorineural hearing loss to conductive
|Criteria||Sensorineural hearing loss||Conductive hearing loss|
|Anatomical Site||Inner ear, cranial nerve VIII, or central processing centers||Middle ear (ossicular chain), tympanic membrane, or external ear|
|Weber Test||Sound localizes to normal ear||Sound localizes to affected ear (ear with conductive loss)|
|Rinne Test||Positive Rinne; Air conduction > Bone conduction (both air and bone conduction are decreased equally, but the difference between them is unchanged).||Negative Rinne; Bone Conduction > Air Conduction (Bone/Air Gap)|