Tympanic perforations and hearing loss: Involved factors

Aim. Tympanic perforations can lead to hearing loss which magnitude ranges from negligible to 50 dB. This variability has always been related to location and size of the perforation: the conductive hearing loss is greater as perforation size increases and if the posteroinferior quadrant is involved. However these considerations were suggested by clinical experiences more than clinical studies. Methods. The study enrolled 186 subjects affected by simple tympanic perforations. Eighty-nine patients had small perforations involving one tympanic quarter (group A); half membrane was damaged in 53 subjects (group B); larger perforations occurred in 44 ears (group C). Each subject underwent pure tone audiometry to determine air-bone gap for every frequency commonly tested. Results. Patients were subdivided in three groups depending on perforation size. Group A patients showed a 20 dB air-bone gap; group B subjects showed a 22 dB air-bone gap; group C had a 31 dB air-bone gap. These differences were significant for lower frequencies (0.25-0.5-1 KHz). As regards on location of the perforations the ascertained differences were not generally significant.Conclusion. The results obtained demonstrate that hearing loss in patients with eardrum perforations depend on perforation's size; the location of the perforation is not, or less relevant, concerning the hearing aspect.