Which of the following conditions causes maximum hearing loss

CONDUCTIVE HEARING LOSS AVERAGE HEARING LOSS SEEN IN DIFFERENT LESIONS OF CONDUCTIVE APPARATUS 1. Complete obstruction of ear canal: 30 dB 2. Perforation of tympanic membrane (It varies and is directly propoional to the size of perforation): 10-40 dB 3. Ossicular interruption with intact drum: 54 dB 4. Ossicular interruption with perforation: 38 dB 5. Malleus fixation: 10-25 dB 6. Closure of oval window: 60 dB Note here that ossicular interruption with intact drum causes more loss than ossicular interruption with perforated drum. Ref:- Dhingra; pg num:-29