| Central hearing loss | |
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| Classification and external resources | |
Location of the Primary Auditory Cortex in the Brain |
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| MeSH | D006313 |
Central hearing loss is a form of sensorineural hearing loss caused by damage to the auditory pathways. When the damage is to the primary auditory cortex, the impairment is called "cortical deafness".
Cortical deafness is an auditory disorder where the paitent is inable to hear sounds but has no apparant damage to the anatomy of the human ear (see auditory system). It can be thought of as the combination of pure word deafness and auditory agnosia. Cortical deafness is caused by bilateral cortical lesions in the primary auditory cortex located in the temporal lobes of the brain [2] In most instances, the cause is bilateral embolic stroke to the area of Heschl's gyri. Cortical deafness is extremely rare with only twelve reported cases. Paitents with cortical deafness cannot hear any sounds, that is, they are not aware of sounds including non-speech, voices, and speech sounds [1].
It is thought that cortical deafness could be a part of a spectrum of an overall cortical hearing disorder [2]. In some cases, paitents with cortical deafness have had recovery of some hearing functions resulting in parital auditory deficits such as Speech agnosia [2]. Speech agnosia (also known as pure word deafness) is the inability to recognize speech while hearing maintains intact [1] Note that this syndrome might be difficult to distinguish from a bilateral temporal lesion such as described above.
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