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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 9  |  Issue : 2  |  Page : 122-127

Hearing impairment in patients with oral submucous fibrosis: Our experiences


1 Department of Otorhinolaryngology and Head and Neck Surgery, IMS and SUM Hospital, Siksha “O” Anusandhan University, Bhubaneswar, Odisha, India
2 Central Research Laboratory, IMS and SUM Hospital, Siksha “O” Anusandhan University, Bhubaneswar, Odisha, India

Date of Submission04-Dec-2021
Date of Decision21-Dec-2021
Date of Acceptance06-Jun-2022
Date of Web Publication31-Aug-2022

Correspondence Address:
Prof. Santosh Kumar Swain
Department of Otorhinolaryngology and Head and Neck Surgery, IMS and SUM Hospital, Siksha “O” Anusandhan University, K8, Kalinga Nagar, Bhubaneswar - 751 003, Odisha
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/sjoralsci.sjoralsci_63_21

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  Abstract 


Introduction: Oral submucous fibrosis (OSMF) is a premalignant condition of the oral cavity. The pathological changes in OSMF often affect mucosa, submucosa, and underlying muscles in the oral cavity and pharynx. The pathological changes of the tubal and para-tubal muscles can affect the function of the Eustachian tube. The Eustachian tube dysfunction in OSMF often may result in hearing impairment.
Aim: This study aims to evaluate the effect of OSMF on Eustachian tube function resulting in hearing impairment.
Materials and Methods: This prospective study was carried out at a tertiary care teaching hospital of Eastern India from June 2019 to July 2021. There were 68 patients with OSMF enrolled in this study by simple random sampling. In this study, 68 patients (136 ears) suffering from OSMF with hearing impairment or fullness/blockage feeling in the ear who participated in this study. The clinical profile of these patients was worked out by taking a detailed history and clinical examination. All the patients underwent audiological evaluation with pure-tone audiometry and tympanometry.
Results and Discussion: Out of 68 patients, 42 (61.76%) were male and 26 (38.23%) were female with a male-to-female ratio of 1.61:1. The age ranges of the patients who participated in this study were between 18 years and 65 years. Pure-tone audiometry showed normal hearing in 86 (63.24%) ears, mild conductive hearing loss in 31 (22.79%) ears, moderate conductive hearing loss in 14 (10.29%) ears, and sensorineural hearing loss in 5 (3.68%) ears.
Conclusion: The Eustachian tube may be blocked by the effect of the OSMF and result in hearing loss. Hence, while treating OSMF, hearing impairment in OSMF has to be kept in mind.

Keywords: Eustachian tube, hearing loss, oral cavity, oral submucous fibrosis, pharynx


How to cite this article:
Swain SK, Das S. Hearing impairment in patients with oral submucous fibrosis: Our experiences. Saudi J Oral Sci 2022;9:122-7

How to cite this URL:
Swain SK, Das S. Hearing impairment in patients with oral submucous fibrosis: Our experiences. Saudi J Oral Sci [serial online] 2022 [cited 2022 Oct 4];9:122-7. Available from: https://www.saudijos.org/text.asp?2022/9/2/122/355227




  Introduction Top


Oral submucous fibrosis (OSMF) is a common collagen disease of the oral cavity which has a great similarity to localized scleroderma or morphea.[1] OSMF is a well-recognized potentially malignant disorder of the oral cavity with the characteristic of fibrosis of the mucosal lining at the upper digestive tract affecting the oral cavity and oropharynx.[2] OSMF is also known as diffuse OSMF, idiopathic scleroderma of mouth, idiopathic palatal fibrosis, sclerosing stomatitis, and juxta-epithelial fibrosis.[3] OSMF is commonly seen in India and neighboring countries. The incidence of OSMF in India varies from 0.2% to 0.5% with a higher percentage being seen in the southern part.[4] The etiological factors for OSMF are thought to be multifactorial such as betel quid chewing, excessive use of spices and chilies, nutritional deficiency, infective agents, genetic susceptibility, and autoimmunity.[5] Areca nut is considered as the major etiologic agent where chewing of betel quid (areca catechu, lime, and tobacco) as well other areca nut containing products (e.g., pan masala and gutkha) for freshening of the mouth.[6] OSMF is characterized by progressive fibrosis involving mucous membrane of the oral cavity, mainly buccal mucosa, soft palate, lip mucosa, and anterior pillars. Involvement of the muscles soft palatal muscles often affects the function of the  Eustachian tube More Details.[7] There is a paucity of information related to the involvement of OSMF in the adjacent areas of the oral cavity such as the ear (Eustachian tube), oropharynx, hypopharynx, larynx, and very few studies are available to correlate to the Eustachian tube dysfunction with different clinical stages of OSMF. There are very few studies available for correlating hearing loss and OSMF. This study attempts to evaluate the impact of OSMF on Eustachian tube function and hearing impairment.


  Materials and Methods Top


This is a prospective and descriptive study carried out at a tertiary care teaching hospital of eastern India from June 2019 to July 2021 at a teaching Hospital, Odisha, India. There were 68 patients with OSMF enrolled in this study by simple random sampling. The age group of the participating patients was 18–65 years. The sample size was calculated according to the assumptions of hearing impairment globally with 5% of prevalence, 2 times the number of successes, and 95% probability. According to the formula, the sample size was 93, but due to the unavailable of patients 68 patients were enrolled for this study. The study was approved by the Institutional Ethics Committee (IEC) with reference number IEC/SOA/IMS/2019/12/24.4.2019. After obtaining written informed consent, the clinical profiles of the OSMF patients were taken through case history and clinical examination. Patients of OSMF with hearing impairment or feeling of blockage sensations in-ear were included in this study. Detailed history taking and clinical examinations like examinations of the ear, oral cavity, and oropharynx were done for each patient who participated in this study. The detailed ear and oral cavity examinations were done by senior authors. Patients with ear infections, tympanic membrane perforation, cholesteatoma, or previous surgery in-ear and congenital abnormalities in the ear were excluded from this study. The audiological assessment was done on each patient who participated in this study. Pure-tone audiometry and tympanometry were performed in each patient to assess the hearing and middle ear status. The pure tone audiometry determines the type and degree of hearing loss and the impedance audiometer was used for assessing the function of the Eustachian tube. The audiological evaluation was done by using a clinical audiometer graphic audiometer classic I-S and Eustachian function evaluation by impedance tympanogram Maico MI 34 (tympanometric evaluation). The audiometric and tympanometric evaluations were performed by an experienced audiologist and output was obtained as a graph. In pure tone audiometry, the pure tone is delivered to the ear by headphones for air conduction (AC) and by a bone vibrator for bone conduction (BC). The hearing level in decibels above the normal threshold was plotted. The frequency was ranged from 250 to 8000 Hz during performing audiometry. The pure-tone average is the average of the hearing threshold levels at 500, 1000 and 2000 Hz.[7] The hearing impairment can be graded into different types by the AC threshold, i.e., 10–15 decibel indicate normal hearing; 16–25 decibel indicate minimal hearing loss; Mild hearing loss indicate 41–55 decibel; moderate indicates 56–70 decibel; moderate to severe indicate 71–90 decibel, severe >90 decibel and profound hearing loss more than 98 decibels. Hearing impairment can be classified into normal, conductive, mixed, or sensorineural hearing loss. The overall degree and type of hearing loss were described in a single word by using the quantitative and qualitative types of hearing impairment together.

Statistical package for the social science (SPSS) Statistics for Windows, version 20, was used for all statistical analyses (IBM-SPSS Inc., Chicago, IL, USA).


  Results Top


There were 68 patients with OSMF enrolled in this study. Out of 68 patients, 42 (61.76%) were males, and 26 (38.23%) were females with a male-to-female ratio of 1.61:1. The age ranges of the patients who participated in this study were between 18 years to 65 years. There were two groups of the age of the patients participating in the study such as 18–40 years and 41–65 years. There were 45 (66.17%) patients in the age range of 18–40 years and 23 (33.82%) patients in the age range of 41–65 years [Table 1]. The patients of OSMF presented with difficulty in mouth opening, ulcerations in the oral cavity, intolerance to spicy food, burning sensations in the mouth, and inability to protrude the tongue. In this study, 31 (45.58%) patients presented with hearing impairment, 37 (54.41%) with blockage feeling in the ear, 16 (23.52%) presented with difficulty in mouth opening, 12 (17.64%) with ulcers in the oral cavity, and 14 (20.58%) presented with intolerance to spicy foods and burning sensation in the mouth [Table 2]. Pure-tone audiometry showed normal hearing in 86 (63.24%) ears, mild conductive hearing loss [Figure 1] in 31 (22.79%) ears, moderate conductive hearing loss in 14 (10.29%) ears, and sensorineural hearing loss in 5 (3.68%) ears [Table 3]. Tympanometry was performed in all participants. Out of 136 ears examined, a normal tympanogram was recorded in 18 (13.23%) ears. Type-B tympanogram [Figure 2] was found in 62 (45.58%) ears and Type-C in 56 (41.17%) ears [Table 4].
Figure 1: Pure tone audiometry showing mild conductive hearing loss

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Figure 2: Type B tympanogram

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Table 1: Demographic details of patients with oral submucous fibrosis participated in the study

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Table 2: Clinical profile of the oral submucous fibrosis patients

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Table 3: Oral submucous fibrosis with hearing impairment

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Table 4: Types of tympanograms in oral submucous fibrosis patients

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The Chi-square (χ2) test has degrees of freedom of (r-1) (c-1), where r is the number of rows and c is the number of columns. The χ2 value is 1.9209, and the corresponding P value is 0.7503, which is higher than the P value of 0.05, indicating that there is no significant difference. To summarize, there is no link between hearing impairment and tympanogram types [Table 5]. Person Chi-square test is done for two groups sex and clinical profile of the OSMF patients' odd ratio of the category is 0.556 for unilateral, 0.798 bilateral, 1.716 for Blockage sensation in the ear, 2.200 difficulties in mouth opening, 0.840 in ulcers in the oral cavity and 0.543 for intolerance to spicy foods and burning sensation in the mouth [Table 6].
Table 5: Chi-square test and its application in hypothesis testing

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Table 6: Person Chi-square test and odds ratio of sex and oral submucous fibrosis patients

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  Discussion Top


OSMF is a common disease of the oral cavity and oropharynx.[8] OSMF is a well-established precancerous condition affecting the mucosa of the oral cavity.[9] OSMF was first described by Schwartz in 1952 among 5 east African women of Indian Origin.[10] This was followed by the first description of this clinical entity in India in 1953 in quick succession.[11] In 1966, Pindborg and Sirsat described the OSMF as an insidious chronic disease affecting any part of the oral cavity and sometimes the pharynx.[12] Areca nut chewing, tobacco smoking, and chilies are the important causative factors among genetically predisposed patients.[13] Areca nut chewing is a traditional practice in the Indian subcontinent and it still retains its popularity as a chewing habit.[14]

OSMF occurs at any age group but is most commonly found in adolescents and adults, particularly between 16 and 35 years.[15] In this study, the majority of the patients are in the age group of 18–40 years. OSMF is predominantly found in South-east Asia and the Indian subcontinent with few reported cases from South Africa, the United Kingdom, and Greece.[16] In India, the prevalence rate of OSMF is approximately 0.2%–0.5%.[17] The cause behind the increased prevalence of OSMF in India is due to an upsurge in the popularity of commercially prepared tobacco and areca nut preparations such as gutkha, pan masala, mawa, flavored supari, etc.[17] Although occasionally preceded by and/or associated with the formation of the vesicle, it is often associated with juxta-epithelial inflammatory reaction followed by a fibroelastic change of the lamina propria and epithelial atrophy resulting in stiffness of the oral cavity mucosa, causing trismus and inability to open mouth.[18] Early symptoms in OSMF are burning sensation in the oral cavity, presence of vesicles, and recurrent generalized inflammation of the mucosa lining the oral cavity. Once the disease progress, there is evidence of blanching and fibrosis of the oral cavity mucosa. OSMF with progressive fibrosis causes stiffening of the mucosa, leading to difficulty in mouth opening, speaking, and swelling, as well as change of taste. Involvement of the mucosa of the nasopharynx may cause ear pain and nasal twang.[19] In this study, there were 23.52% of patients presented with difficulty in mouth opening, and 20.58% of patients presented with intolerance to spicy foods and burning sensation in the mouth.

The normal hearing mechanism includes the entry of sound waves into the external auditory canal, then vibrating the tympanic membrane and ossicles which are transmitted to the inner ear. The alternating changes in pressure stimulate the basilar membrane on which organ of Corti is present, moving the hair cells. This movement of the sensory hair cells causes the transmission of impulses along the auditory nerve to the brain. A small part of normal hearing causes direct transmission of sound waves to the inner ear through the bones of the skull i.e., the external auditory canal and middle ear are bypassed. This type of hearing is called BC. The Eustachian tube connects the middle ear to the nasopharynx. The diameter of the Eustachian tube is approximately 3 mm. The cartilaginous part of the Eustachian tube constitutes the medial two-thirds, whereas the lateral third (close to the middle ear) is the bony part.[20] Four muscles are usually associated with the Eustachian tube such as the tensor veli palatini, levator veli palatini, salpingopharyngeus, and tensor tympani. Each of these muscles is implicated in tubal function. The Eustachian tube is usually closed, but it opens during swallowing, yawning, or sneezing, so permitting equalization of the middle ear and atmospheric pressure.[21] The patency and ventilatory function of the Eustachian tube may be impaired if any of these muscles are affected by the OSMF.[20] The main muscles attached to the Eustachian tube and soft palate are the tensor veli palatini and levator veli palatini may be affected by the OSMF. These two muscles and other accessory muscles are often called palatal/para-tubal muscles. The cartilaginous part of the Eustachian tube and its musculatures is a dynamic organ and its patency and ventilatory function may be impaired by OSMF. One study evaluated the function of the Eustachian tube with help of pure-tone audiometry and found significant hearing loss in patients with OSMF.[22] There was a significant correlation seen between the degree of fibrosis of the palatal muscles and hearing impairment.[23] In this study, 45.58% of the study population with OSMF complained of hearing impairment. In this study, 136 (68 patients) ears, 22.79% showed a mild conductive hearing loss, 10.29% showed a moderate conductive hearing loss, and 3.68% presented with sensorineural hearing loss. The presence of a sensorineural hearing loss in OSMF patients cannot be explained based on the Eustachian tube dysfunction rather than accidental findings and maybe age-related hearing loss. Pure-tone audiometry and impedance audiometry are two important tools for the assessment of hearing status and Eustachian tube functions. In this study, the majority of the patients with OSMF showed type-B and type-C tympanogram. Based on AC-BC gaP values, the hearing gloss is usually quantified as different categories such as 0–25 decibel-Normal hearing; 26–40 decibel-Mild deafness; 41–55 decibel-moderate deafness; 56–70 decibel-moderate to severe hearing loss; 71–90 decibel-severe hearing loss and more than 90 decibel suggests profound hearing loss.[24] However, the χ2 value is 1.9209, and the corresponding P = 0.7503, which is higher than the P = 0.05, indicating that there is no significant difference or there is no link between hearing impairment and tympanogram types.

OSMF is a debilitating but preventable oral disease. The management of the OSMF is based on the degree of involvement and timely diagnosis. OSMF requires trismus correction, reconstructive surgery for any simultaneous malignancy of the oral cavity.[25] Submucosal intralesional injections or topical application of steroids may be helpful to prevent further progress of OSMF. Topical application of steroids is useful in patients of OSMF with ulcers and painful mucosa of the oral cavity. The therapeutic effect of the steroids is mainly anti-inflammatory with direct healing action.[26] The steroid also acts as an immunosuppressive agent for the prevention of fibro-productive inflammation in OSMF lesions, so ameliorating the fibro-collagenous condition as in OSMF.[27] Topical use of hyaluronidase is helpful to improve the symptoms more quickly than steroids alone. Hyaluronidase can be added to the intralesional steroid preparations which give better long-term outcomes than either agent.[28] Hyaluronidase usually degrades into a hyaluronic acid matrix which promotes lysis of the fibrinous coagulum as well as activating specific plasmatic mechanism. Placental extract inpatient with OSMF prevents damage of the mucosal lining of the oral cavity by its anti-inflammatory effect.[29] Cessation of the areca nut chewing along with submucosal administration of placental extract provides a marked improvement in OSMF.[29],[30] Patients of OSMF with trismus are usually advised to do mouth opening exercises for at least 20 min daily.[31],[32] This study has a relatively small sample size and performed in a single center. However, the clinical profiles and management of the hearing impairment among OSMF patients will definitely provide a management strategy and its awareness among clinicians. e affected in OSMF


  Conclusion Top


OSMF is a chronic, insidious, disabling disease affecting the mucosa of the oral cavity and oropharynx. OSMF involves palatine muscles which decrease the patency of the Eustachian tube leading to conductive hearing loss. Patients with OSMF should be screened for hearing impairment and advised about appropriate treatment. Because of the lack of curative treatment and precancerous nature of this disease, it is often essential to follow up with the patients on regular basis along with available treatment for decreasing the fibrosis bands in the oral cavity and pharynx. It is concluded that in OSMF, the Eustachian tube may be blocked and cause hearing impairment. Hence, while treating the OSMF patients, hearing impairment has to be kept in mind. The hearing impairment is not well studied in relation to staging, grading, and interincisional distance in OSMF patients. Hence, further studies are needed to elucidate the association of stages of OSMF and prevalence of Eustachian dysfunction.

Financial support and sponsorship

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Conflicts of interest

There are no conflicts of interest.



 
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