Download Types and Causes of Peripheral Hearing Loss

TYPES AND CAUSES OF PERIPHERAL HEARING LOSS
TYPES OF HEARING LOSS
Conductive – Cochlea and auditory neural systems OK, problem with sound transmission
through the ear canal and/or middle ear.
Sensorineural – Ear canal and middle ear OK, cochlea or auditory neural system not fully
functioning.
Mixed – A combination of conductive and sensorineural.
COMMON CAUSES OF PERIPHERAL HEARING LOSS
CONDUCTIVE
Wax blockage in ear canal; middle ear infections (otitis media), glue ear (otitis media with
effusion OME), perforated eardrum; no or malformed ear canal (atresia/stenosis of canal).
Middle ear problems such as otitis media, partly due to Eustachian Tube
dysfunction/abnormality, may often occur in children with Down’s syndrome and cleft palate.
SENSORINEURAL
Inherited causes (family history of hearing loss alone), in-utero infections (eg, CMV), hearing
loss as part of a syndrome (eg, Pendred’s), neurodegenerative disorders (eg,
neurofibromatosis), need for post natal or later intensive care with effects on the cochlea and
auditory nerve (eg, prematurity and jaundice, meningitis). Some causes of hearing loss are
associated with sudden loss (such as the presence of an enlarged vestibular aqueduct or
occurrence of a perilymph fistula), or a gradual decline in hearing.
MIXED
Most commonly occurring due to an ear infection present in a child who normally has a
sensorineural hearing loss (SNHL). Can be present permanently in children with hearing loss
as part of CHARGE Association. Hearing thresholds become temporarily elevated due to the
conductive overlay caused by a middle ear infection. For many young children with SNHL, the
degree of hearing loss may fluctuate repeatedly as a result of ear infections.
Further Reading; Northern JL and Downs MP “Hearing in Children” (5th ed). Lippincott,
Williams & Wilkins, MD. 2002