When the perforation size was relatively large, the sound transmission via acoustic route would became dominant and air-bone gap would increase more by phase cancelation at round window in posterior TM perforation rather than in anterior TM perforation [2, 3]. Unfortunately, most of patients who were included in our study had small perforation size within 30% of TM (n=34/44, 77%). The authors agree with your comments which we did not mention in the discussion.