The Effect of Tympanic Membrane Perforation on Hearing

Background: Tympanic membrane perforation is a relatively common finding that is caused by various factors, including trauma and infection.Conductive hearing loss of varying degrees can be caused by a perforated eardrum.Objective: The aim of this study was to evaluate the effect of size and site of tympanic membrane perforation on hearing.Methods: This is a case-control study involving patients with tympanic membrane perforation at the ENT Department-Al-Jumhori Teaching Hospital, Mosul, Iraq, from September 1st, 2010, to September 1st, 2011.All the data were collected and compared with normal control persons with no tympanic membrane perforation. Results:The study included 78 patients with tympanic membrane perforation.Fifty-eight patients (74.3%) have unilateral perforation, while the other twenty patients (25.7%) have bilateral perforation.A total of 98 ears with tympanic membrane perforation were included in this study compared with 100 control persons with no perforation.The mean age of patients was 35.3 years, while the control average age was 42.59 years.Hearing level in patients with perforated tympanic membrane was as that, in 16 patients, the hearing level was 0-20 dB (16.3%), 60 patients hearing level 21-40 dB (61.22%), 20 patients hearing level 41-60 dB (20.4%) and two patients hearing level more than 60 dB (2.04%).In comparison, in the control group, 89 patients the hearing level was 0-20 dB (89%), seven patients had a hearing level of 21-40 dB (7%), three patients had a hearing level of 41-60 dB (3%) and one patient's hearing level more than 60 dB (1%).Moreover, posteroinferior perforation was the most common site of perforations.Conclusion: Our results revealed that the larger the perforation, the greater the hearing impairment.Moreover, posterior perforations of the tympanic membrane were the most common types.They significantly caused more hearing loss, possibly even greater than those due to larger perforations located elsewhere.