answer: b) As (DHINGRA 6TH ED, P-24* Type A- normal tympanogram* Type As- (Low compliance) otosclerosis, malleus fixation* Type AD- (High compliance) ossicular discontinuity or thin and lax tympanic membrane* Type B- (No Change in compliance with pressure changes) middle ear fluid, thick tympanic membrane.* Type C- (Maximum compliance occurs with negative pressure in excess of 100 mm of H2O) retracted tympanic.OTOSCLEROSIS or OTOSPONGIOSIS* Disease of bony labyrinth where spongy bone replaces normal enchondral layer of bony otic capsule* Most often the otosclerotic focus involves stapes leading to stapes fixation and CHLEtiology* Family history present* Autosomal dominant* Common in Indians; Age 20-30 yrs* Females affected twice more than males.* But in India males are more affected* May be initiated or made worse by pregnancy, menopause, after an accident or a major operation* Van der hoeve syndrome- triad of Osteogenesis imperfecta, Blue sclera and Otosclerosis* Virus involved - Measles virusTypes* Stapedial otosclerosis causing stapes fixation and CHL is the most common variety* Fistula ante fenestrum - in front of oval window is the site of predilection (anterior focus)* Cochlear otosclerosis - causes SNHLMicroscopic* Immature focus - vascular spaces, osteoclasts, osteoblasts & fibrous tissue - stains blue on HE staining (Blue mantles of Manasse)* Mature focus - less vascular with lot of fibrous tissue and few osteoblasts - stains red on HE stainingSymptoms and Signs* Hearing loss - painless progressive bilateral CHL* Paracusis willisi - hears better in noisy surroundings* Tinnitus, Vertigo, Monotonous soft speech* TM - normal and mobile* Schwartz sign - flamingo pink blush or reddish hue seen on the promontory through TM - indicates active focus* TFTs- negative Rinne, Weber lateralized to the ear with greater hearing loss* In some cases a dip in the bone conduction curve appear at 2000Hz which disappears after successful stapedectomy (Carhart's notch)* Bezold's triad - absolute negative Rinne's, raised lower tone limit, prolonged bone conductionTreatment* Medical- Sodium fluoride* Surgical: Stapedectomy/ Stapedotomy with a placement of prosthesis - treatment of choiceSelection of patients for Stapes surgery* Hearing threshold for air conduction should be > 30 DB* Average air-bone gap should be atleast 15 DB* Rinne negative for 256 and 512 Hz* Speech discrimination score > 60%