THE EFFECT OF AREA AND SITE OF TYMPANIC MEMBRANE PERFORATIONS ON HEARING THRESHOLD AMONG SUDANESE PATIENTS
Abstract
Background: Chronic otitis media is one of the commonest otological problems among Sudanese children and adults. The disease presents with perforations of the eardrum, discharging ears and varying degrees of hearing loss.
Objective: The objective of this work is to study the effect of the area and the site of the tympanic membrane perforation on hearing threshold among Sudanese patients.
Patients & Methods: This is a prospective hospital-based study conducted at Ibn Sina and Khartoum Teaching Hospitals-Otolaryngology Departments (E.N.T), in the period from 1 April – to the 30 of July 2002. Information from both the control and study subjects was taken, using protested questionnaire. Twenty-five normal subjects (50 ears) were taken as a control group selected randomly from the healthy population; their hearing thresholds were tested in order to find a reference level. Seventy-one consequtive patients with uni - or bilateral chronic suppurative otitis media (100 perforated ears) were taken as a study group.
Results: The hearing threshold of the control Sudanese subjects was 17dB. This was obtained by computing the mean for the human speech frequencies (500, 1000, 2000Hz). The lower frequencies were affected regardless of side, site and area of the perforation. Conductive hearing loss was the commonest type (79%). The commonest site of the perforations was the central site (90%) followed by posteroinferior 3%. The commonest area of tympanic membrane perforations was the subtotal area (54%), followed by large central perforations (25%). The greatest hearing loss was found to be in the posteroinferior and anterio-superior perforation of the drum compartment.
Conclusion and recommendations From this study, we can conclude that regardless of the area, the site of tympanic membrane perforation is the most important factor affecting hearing threshold. The posterior central perforation having the greater effect for this reason, any patients with the posteroinferior and anterio-superior perforations should have repair of tympanic membrane (myringoplaty).
References
2- Berger G. Nature of spontaneous tympanic membrane perforation in acute otitis media in children. Journal of Laryngology and Otology1989; 103: 1150-1153.
3- Mills R.P Management of chronic suppurative otitis media. Scott Brown’s Otolaryngology, 6th ed. Alan G Kerr (General Editor). Butterworth-Heinemann (Pub) 1997; Vol. 3(10): 1-15.
4- Ueda, H., Nakata-S, and Hoshino, M. The effects of Effusion in the Middle Ear and the 5- Perforation of Tympanic Membrane on Otoacoustic Emissions in Guinea Pigs. Otolaryngology Department, Nagoya University 1998; 122(1-2): 41-46
5- American Academy of Otolaryngology–Head and Neck Surgery www.intrnet-org/ENT Net health into/ear/perforation 2002;13/04/23.
6- Gina berg, Irwin and White-Thomas P Otological disease and examination. In: Katz’s (Ed.) Handbook of clinical audio logy, 4th Edition Baltimore, Williams & Wilkins. 1994; P.14.
7-Yagi, H.I, The Pattern of Diseases of the Ear in Sudanese Patients. Sudan Medical Journal, Sudan Medical Association. 1989; Vol. 27 (1-4): 44-47.
8-Ross J.M, Rosservalents, L. and Holly-Hosford Dunn Application in Diagnostic Audiology. Audiology Diagnosis. Andreoseils (Ed). Thieme (Pub) New York. 2000; 11, 227-251.
9-Yung M.W. Myringoplaty: Hearing Gain in Relation to Perforation Site. The Journal of Otolaryngology 1983; 97: 11-17.
10- Bamanie A.H. Effect of tympanic membrane perforation on hearing loss among Saudi adults, a thesis submitted for MSC Degree in Audio logy. 1996; 1-144
11- American Academy of Otolaryngology –Head and Neck Surgery Acoustic effects of middle ear-disease. Acoustical aspects of chronic ear surgery. Goode R.L (Ed). American Academy of Otolaryngology 1987; (Pub) 80187: 27-28.
12- Austin D.F. Sound conduction of the diseased ear . Journal of Laryngology and Otology 1978; 92/5, 367-393.
13- Anthony W.P., Harrison C.M., Tympanic membrane perforation: effect on audiogram. Archives of Otolaryngology 1972 ; 95: 506-510.
