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HEARING LOSS. DR SUDEEP K.C. CLASSIFICATION OF HEARING LOSS. AUDITORY PATHWAYS. CONDUCTIVE HEARING LOSS . Characteristics of Conductive hearing loss are: Negative Rinne test(BC>AC) Weber lateralised to defective ear. Normal absolute bone conduction. Low frequencies affected more.
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HEARING LOSS DR SUDEEP K.C.
CONDUCTIVE HEARING LOSS • Characteristics of Conductive hearing loss are: • Negative Rinne test(BC>AC) • Weber lateralised to defective ear. • Normal absolute bone conduction. • Low frequencies affected more. • Audiometry shows bone conduction is better than air conduction with A-B gap. • Loss is more than 60 db.
Causes of Conductive loss • Congenital causes. • Acquired causes. CONGENITAL CAUSES: • Meatal atresia. • Fixation of the stapes foot plate. • Fixation of malleus head. • Ossicular discontinuity
ACQUIRED CAUSES: • Any obstruction in the ear canal E.g. Wax, Foreign body, tumor etc. • Perforation of TM- traumatic or infective. • Fluid in the middle ear- Otitis media , Haemotympanum. • Mass in the middle ear. • Disruption of ossicles – Trauma, CSOM. • Fixation of ossicles – Otosclerosis, Tympanosclerosis.
Management • Removal of Canal obstruction. • Removal of the fluid. • Removal of mass from middle ear. • Stapedectomy - Otosclerotic fixation of stapes footplate. • Tympanoplasty. • Hearing Aid.
TYMPANOPLASTY It is an operation to : • Eradicate disease in the middle ear. • To reconstruct hearing mechanism. • If there is only repairing of TM – Myringoplasty. • If there is reconstruction of Ossicular chain- Ossiculoplasty. • If both TM and Ossicular chain repair- Tympanoplasty.
MYRINGOPLASTY • It is the repair of tympanic membrane . • Graft material: Temporalis fascia or perichondrium and sometimes from the cadaveric tympanic membrane, vein, fascia. • Repair can be done by two techniques: • Under lay technique. • Over lay technique.
OSSICULAR RECONSTRUCTION • It is required when there is destruction or fixation of Ossicular chain. • Most common defect is long process of the Incus. Repair of ossicular chain: • Can be achieved by the use of autograft incus or cartilage, or homograft ossicles or the prosthetic implants made of ceramic or teflon.
SENSORINEURAL HEARING LOSS Characteristics of SNHL are: • Positive Rinne test (AC>BC). • Weber lateralised to better ear. • Bone conduction reduced in ABC test. • More often involving the high frequencies. • No gap between the air and bone conduction curve on audiometry. • Loss may exceed 60 db.
CAUSES OF SNHL: • Congenital. • Acquired: • Infection of the labyrinth. • Trauma to the labyrinth or VIII nerve. • Noise induced hearing loss. • Ototoxic drugs. • Presbycusis. • Meniere’s disease. • Acoustic Neuroma.
DIAGNOSIS: • History. • Severity of deafness. • Types of audiogram-whether loss is of high frequency or of low frequency. • Site of the lesion- Cochlear , Retro –Cochlear and Central.
MANAGEMENT • Early detection of SNHL is important as measures can be taken to stop its progress, reverse it or to start an early rehabilitation programme. • SYPHILIS- High dose of penicillin and steroids. • HYPOTHYROIDISM- Replacement therapy. • SEROUS LABYRINTHITIS- Reverse by attention to middle ear infection. • MENIERE’S DISEASE- Early management can prevent further episodes of vertigo and hearing loss. • OTOTOXIC DRUGS should be discontinued. • REHABILITATION.