|Year : 2016 | Volume
| Issue : 1 | Page : 16-19
Assessment of hearing loss in tympanic membrane perforation
Haider W Alsarhan1, Mohammed R Dawood1, Abd Alhussen Kareem Jwery1, Ammar H Khammas1, Abbas K Hamad2
1 Otolaryngology Department, College of Medicine, Al-Mustansiriyha University, Baghdad, Iraq
2 Al-Yarmouk Teaching Hospital, Baghdad, Iraq
|Date of Submission||15-Jun-2016|
|Date of Acceptance||20-Jul-2016|
|Date of Web Publication||28-Sep-2016|
Haider W Alsarhan
Assistant Professor, College of Medicine, Al-Mustansiriyha University, Baghdad
Source of Support: None, Conflict of Interest: None
Tympanic membrane perforation is a common problem and causes hearing disability, and many factors can affect the degree of hearing loss.
The aim of this study was to assess the degree of hearing loss in relation with the size and site of tympanic membrane perforation.
Patients and methods
This prospective study was conducted at Al-Yarmouk Teaching Hospital during the period from February 2015 to February 2016 on 75 patients (93 ears) with tympanic membrane perforations. The size and site of perforations were evaluated under the microscope and classified according to the size (small, moderate, and large), and the site (anteroinferior, anterosuperior, posteroinferior, and posterosuperior quadrants). Hearing loss was measured in each case with pure-tone audiometry and its relation with these parameters was analyzed.
There was an increase in hearing loss with the increase in the size of perforation. Perforation locations had an impact on hearing loss; this was statistically significant, especially in the posteroinferior quadrant if compared with other quadrants, as P value was 0.037.
The size and site of tympanic membrane perforation had a significant effect on the magnitude of hearing loss.
Keywords: hearing loss, tympanic membrane perforation, conductive hearing loss
|How to cite this article:|
Alsarhan HW, Dawood MR, Jwery AK, Khammas AH, Hamad AK. Assessment of hearing loss in tympanic membrane perforation. Adv Arab Acad Audio-Vestibul J 2016;3:16-9
|How to cite this URL:|
Alsarhan HW, Dawood MR, Jwery AK, Khammas AH, Hamad AK. Assessment of hearing loss in tympanic membrane perforation. Adv Arab Acad Audio-Vestibul J [serial online] 2016 [cited 2019 May 20];3:16-9. Available from: http://www.aaj.eg.net/text.asp?2016/3/1/16/191237
| Introduction|| |
The tympanic membrane separates the middle ear from the external ear, measuring 9–10 mm vertically and 8–9 mm horizontally. It transmits sound in the middle ear. It not only performs the conduction of sound waves across the middle ear but also serves as a protection to the middle ear cleft and shields the round window from direct sound waves, which is referred to as ‘round window baffle’ . This shield is necessary to create a phase differential so that the sound wave does not impact the oval and round window simultaneously, and this would dampen the flow of sound energy being transmitted in a unilateral direction from the oval window through the perilymph. It has been found that the effect of the enhanced ratio of the surface area of the tympanic membrane to that of the oval window increases the sound pressure by about 27 dB, whereas the lever action of the ossicles contributes about 3 dB .
Tympanic membrane perforation usually results from trauma or middle ear infections. As perforation on the tympanic membrane reduces the surface area of the membrane available for sound pressure transmission and allows sound to pass directly into the middle ear, it causes a conductive loss that can range from negligible to 50 dB. It has been established that the larger the perforation, the greater the decibel loss in sound perception .
Deafness is a common health problem with physical and psychosocial issues; therefore, tympanic membrane perforation should be treated as early as possible because tympanic membrane perforation leads to serious changes in the tympanic cavity, thus increasing the degree of deafness .
| Aim of the study|| |
The aim of this study was to assess the effect of the size and site of tympanic perforation on the degree of hearing loss.
| Patients and methods|| |
This prospective study was conducted at the Otolaryngology Department of Al-Yarmouk Teaching Hospital from February 2015 to February 2016. All patients attending the ENT consulting unit were assessed by means of detailed history taking and general ENT examination. All patients with tympanic membrane perforation were subjected to computed tomography (CT) scan of the temporal bone for further assessment, and during the period of the study 75 patients (93 ears) were selected according to the inclusion criteria.
- Age between 18 and 50 years.
- Central perforation.
- History of recent perforation not more than 12 months.
- Totally dry perforation without discharge or suppuration for more than 6 months.
- Clear middle ear cavity with intact ossicular chain and clear mastoid air cells with CT scan.
- Audiogram finding showed conductive deafness.
- Active discharging ear.
- Attic perforation.
- Previous ear surgery.
- Presence of sensory neural elements (mixed pattern of pure-tone audiogram).
- Marginal perforation.
- CT scan finding suggesting mastoiditis or mastoid reservoir or ossicular discontinuity.
For the cases included in our study, examinations of the ear of concern were carried out using a Carl Zeiss microscope (GmbH 07740 Jena, Germany) with 200 mm lenses. The size of perforation was classified into three groups: group 1, small perforation with one quadrant involved; group 2, moderate size perforation with two quadrants involved; and group 3, large perforation involving three or all quadrants. The site of perforation was classified according to the quadrant or quadrants involved by the perforation.
The patients’ hearing levels in decibel were assessed with pure-tone audiometry at frequencies 0.25, 0.5, 1000, 2000, 4000, and 8000 kHz in an acoustically treated soundproof room. The audiometer used was the recently calibrated Maico − MA42 clinical diagnostic pure-tone audiometer, in which the air and bone conduction thresholds were determined. Threshold of hearing was determined by measuring averages of air conduction of 0.5, 1, and 2 kHz; degree of hearing loss was classified according to the Clark classification  as follows:
- Normal hearing: hearing threshold less than or equal to 15 dB.
- Minimal hearing loss: hearing threshold between 16 and 25 dB.
- Mild hearing loss: hearing threshold between 26 and 40 dB.
- Moderate hearing loss: hearing threshold between 41 and 55 dB.
- Moderately severe hearing loss: hearing threshold between 56 and 70 dB.
- Severe hearing loss: hearing threshold between 71 and 90 dB.
- Profound hearing loss: hearing threshold more than 91 dB.
The χ2-test was used to test the significance.
Ethical committee approval was obtained and the patient’s consent was taken.
| Results|| |
The current study comprised 75 patients (93 ears); there were 49 male (52.7%) and 44 female (47.3%) patients, and the mean age was 31.5 (±9.771) years.
The most common size of perforation detected was a small size (47.3%), followed by the moderate size (34.4%), whereas the incidence of large size perforations was only 18.3%.
As regards the site of the perforation, there were 35 ears (37.63%) in the anterior half of the tympanic membrane, and 33 ears (35.48%) in the posterior half; 25 ears (26.88%) involved multiple quadrants (two quadrants or more), and the most common site was found in the posterior–inferior quadrant (16 ears; 17.2%). The distribution of the perforation among the ear samples is shown in [Table 1].
As regards the relation of hearing loss with the size of the perforation, [Table 2] shows that the degree of hearing loss was directly related to the size of tympanic membrane perforation.
|Table 2 Hearing loss in relation with the sizes of the tympanic membrane perforations|
Click here to view
For the patients with small perforation (that involve only one quadrant), the most frequent hearing loss was detected in the posterior–inferior quadrant in which there was mild hearing loss in 31.25%. The degree of hearing loss in relation to the site of perforation is shown in [Table 3].
|Table 3 Hearing loss in relation with the sites of tympanic membrane perforations|
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[Table 3] shows that the hearing loss detected in the posterior compartment was worse than that in the anterior compartment. [Table 4] shows the significant difference in hearing loss in the posteroinferior and posterosuperior versus anteroinferior and anterosuperior compartments and a significant difference between posteroinferior versus anteroinferior quadrants. The difference in hearing loss between the posteroinferior quadrant and any of the three quadrants was significant, indicating the strong relation between the posteroinferior quadrant and hearing loss.
| Discussion|| |
The tympanic membrane is an important element for the conduction of the sound waves because of its vibratory characteristic. If perforated, it may lead to conductive hearing loss by reducing the surface area offered for transmission of the sound waves to the ossicular chain.
On analyzing the relationship of the level of hearing loss with the size and site of tympanic membrane perforation, in current study, we found that the severity of hearing loss increases with the increase in the size of perforation. These findings are comparable to that reported in the other studies by Rafique et al. , Mehta et al. , Pannu et al. , Maharjan et al. , Nepal et al. , and Park et al. .
The reason for that relationship between the size of tympanic membrane perforation and hearing loss level was probably due to the hydraulic action arising from the difference in the area of tympanic membrane and of the stapedial footplate, which is the most important factor in impedance matching, and when the surface area is decreased, there will be a decrease in amplification and hearing loss will be proportionate to the size of perforation .
However, Ribeiro et al.  concluded that there was no correlation between the size of tympanic membrane perforations and hearing loss.
As regards the relationship of hearing loss with the site of tympanic membrane perforation, the current study showed that the perforation involving the posteroinferior quadrant resulted in a significantly greater hearing loss if it is compared with perforation involving other quadrants. A similar observation was made by Voss et al. , Ibekwe et al. , Maharjan et al. , Nepal et al. , and Nahata et al.  and this was probably related to the potential effect of loss of the ‘round window baffle’ on hearing threshold.
However, Ibekwe et al. , Rafique et al. , and Park et al.  did not observe significant differences in the hearing loss in the anterior versus the posterior quadrant perforations. In another study conducted by Mehta et al. , they stated that hearing loss did not vary substantially with the site of the perforation, and, if any, it was negligible.
Loss of hearing is a national health problem with significant physical and psychosocial problem. Hence, it is important to diagnose and treat tympanic membrane perforation as early as possible as untreated tympanic membrane perforation leads to ongoing destructive changes in the middle ear, thus adding to further hearing loss .
| Conclusion|| |
The degree of conductive hearing loss increased statistically with increasing size of tympanic membrane perforation, as well as the posterior–inferior quadrant of tympanic membrane perforation.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]