HEARING LOSS

Definition:
Hearing loss, also known as hearing impairment, or anacusis, is a partial or total inability to hear. An affected person may be described as hard of hearing. A deaf person has little to no hearing.
Hearing loss may occur in one or both ears. Hearing disorder are the primary handicapping disability worldwide
Incidence:
in India 20% of population has some degree of hearing loss.
Hearing impairment is common among older adults.
Nearly half of persons who need assistance with hearing disorder are 65 yr and above.
CAUSES
In adults:
Aging(presbycusis)
Noise exposure
Disease, injury
In children :
Ear infection
Congenital defect
External ear: impacted cerum, foreign bodies, external otitis
Middle ear : otitis media, serous otitis, otoscelerosis
Inner ear: meniere’s disease, noise exposure, presbycusis (aging), ototoxicity

Causes of conductive hearing loss.
Congenital (fixation of stapes footplate, ossicular dicontinuity)
buildup of ear wax (impacted cerum),
foreign body in the ear canal,
Otosclerosis
external or middle ear infections (otitis externa or media),
allergy with serous otitis media (fluid in middle ear), trauma to the ossicular chain such as temporal bone fracture,
tumors of the middle ear such as a glomus tumor,
erosion of the ossicular chain (cholesteatoma) and perforation of the tympanic membrane.
DiagnDiagnosis is ordinarily made via observation of an "air-bone gap" on audiometry, meaning that hearing is superior when sound is transmitted in such a way that it bypasses the middle ear ossicular chain. The air-bone gap (ABG) should be at least 10 db.
Characteristics :
Positive rinne’s test i.e AC>BC
Weber lateralised to better ear
No gap between air and bone conduction curve on audiometry
Loss may exceed 60 db
Speech discrimination is poor
Difficult to hear in presence of noise