Comparison of hearing results between the averages of three and four speech frequencies in Type 3 Tympanoplasty

Abstract

Introduction: Hearing assessment after tympanoplasty is done by taking pure tone average. This study was performed to compare the hearing results obtained from the averages of three and four speech frequencies namely 0.5, 1,2KHz and 0.5,1,2,4 KHz in type III tympanoplasty.

Methods: This study was conducted in Tribhuwan university teaching hospital and Kathmandu university hospital, Dhulikhel from October 2006 to November 2009. The pure tone audiogram was performed by Hugson and Westlake method. The audiometry results were reported as per American Academy of Otolaryngology – Head and Neck surgery guidelines. The comparison between the averages of 3 and 4 speech frequencies that are 0.5, 1,2KHz and 0.5,1,2,4 KHz were performed with regard to bone conduction threshold(BCT), air conduction threshold(ACT),air bone gap (ABG) and air bone gap closure. Data analysis was performed using SPSS 13 software.

Results: Comparison between the averages of 3 and 4 speech frequencies between the preoperative BCT and ACT showed difference of 1.5dB and 0.8dB which were statistically significant whereas the difference in ABG was 1dB which was statistically not significant. Similarly post-operative BCT, ACT, ABG showed the difference of 0.3dB, 0.5dB and 0.2dB respectively which were also statistically not significant.

Conclusions: The difference between 3 and 4 speech frequencies averages are small and are statistically not significant but it is still worth to include 4 KHz as this is a high frequency which is likely to be affected by tympanoplsty.