<prompt> Which of the following causes maximum hearing loss?Complete obstruction of ear canalPerforation of tympanic membraneOssicular interruption with intact tympanic membraneOssicular interruption with perforation  <response>: Average hearing loss in different lesions: Complete obstruction of ear canal 30db Perforation of tympanic membrane 10-40 db Ossicular interruption with intact tympanic membrane 54db Ossicular interruption with perforation 38db Closure of oval window can cause 60 db hearing loss 