<prompt> Which of the following is not a cause of conductive hearing loss-CSOMOtosclerosisPresbycusisSerous otitis media  <response>: Ans. is c i.e., Presbycusis Causes of conductive deafnessCongenital causeso Meatal atresiao Fixation of stapes footplateo Fixation of malleus heado Ossicular discontinuityo Congenital cholesteatomaAcquired causeso External ear: Any obstruction in the ear canal, e.g. wax, foreign body, furuncle, acute inflammatory swelling, tumor, atresiao Middle ear : Perforation of tympanic membrane traumatic or infective Fluid in middle ear ASOM, serous otitis media or haemotympanum Mass in middle ear tumors Disruption of ossicles Trauma, CSOM, cholesteatoma Fixation of ossicles otosclerosis, tympanosclerosis, adhesive otitis media Eustachian tube blockage retracted tympanic membrane, serous otitis media 