Cochlear Hearing Loss

Hearing losses are commonly categorized as conductive (drop in stapes vibration), sensorineural (SNHL, nonconductive), or mixed (conductive plus sensorineural); the SNHL can include cochlear and retrocochlear (central)components. Noncentral components (conductive or cochlear problems) are sometimes called peripheral problems. Hearing losses multiply on a linear scale but add on a logarithmic scale (e.g., a 10-fold reduction of cochlear vibration with a 100-fold reduction of stapes vibration produces a 1,000-fold reduction in overall sensitivity or using logarithmic decibel units, the loss is 20dB + 40dB = 60dB). Also note that hearing loss can be different at different frequencies, as summarized graphically on an audiogram. This entry discusses the mechanisms within the cochlea that cause sensorineural hearing loss, and the physiological consequences of these changes.

As for the mechanisms ...