the most medial ossicle in the ossicular chain. Disruption in any of these coupled mechanisms for sound conduction will diminish the sound energy delivered to the cochlea and lead to a CHL. Common example of conditions leading to sudden CHL include cerumen impactions, ear canal foreign bodies, ossicular chain disruption secondary to trauma, eardrum perforations, and acute otitis media (AOM). Chronic otitis media with or without cholesteatoma and otosclerosis are other fairly common otologic conditions leading to CHL, but their onset is generally gradual. Sudden hearing loss may also present as a combination of SNHL and CHL. This is termed mixed hearing loss, as may be the case with some AOM infections. Ultimately, a hearing test or audiogram must be carried out to confirm a specific diagnosis.
TABLE 6.1 Selected Conditions That May Be Associated With Bilateral Sudden Sensorineural Hearing Loss