<prompt> In otosclerosis, tinnitus is due toCochlear otosclerosisIncreased vascularity in lesionConductive deafnessAll  <response>: Cochlear otosclerosis causes sensorineural hearing loss probably due to the liberation of toxic materials into the inner ear fluid, so tinnitus is heard. Clinical features Hearing loss Paracusis willisii Tinnitus: It is more commonly seen in cochlear otosclerosis and in active lesions. Veigo Speech Ref: Diseases of EAR, NOSE and THROAT by PL Dhingra; 7th Edition; page no.95, 96 