European Journal of Cardiovascular Medicine

Chronic otitis media is one of the most common condition of ear in the developing countries and is characterized by irreversible changes in the middle ear cleft.[1] Chronic otitis media have been previously classified into two major types, the tubotympanic and atticoantral COM.[2,3] More recently, COM have been classified into two types i.e. mucosal type and squamosal type, which may be active or inactive. Ossicular chain integrity may be impacted in both active and inactive COM if the posterior third is compromised. In decreasing sequence of frequency, the long process of the incus, stapes crura, body of the incus, and manubrium are involved.[4]

Chronic otitis media is one of the major causes of acquired hearing loss and hearing loss may be present in as high as 80% patients with COM. It has been estimated that COM attribute to approximately 13.8 to 36.2% of hearing impairment.[1]  COM often causes conductive hearing loss and it has been attributed to tympanic membrane rupture, ossicular chain alterations and structural changes in the tympanic membrane and ossicles. The type and severity of hearing loss not only depend upon size of perforation in the pars tensa, but also on other factors such as granulation tissue, mucus, adhesions and tympanosclerosis.[5]

Unlike other SNHL risk factors, COM is thought to be curable with antibiotics or surgery, which are accessible in the majority of nations. However, there is still disagreement over the long-term effects of COM on hearing, which makes it difficult to draw conclusions and offer therapeutic treatment recommendations.[6]

With the above background, the present study was conducted at our tertiary care center to analyse the correlation between type of chronic otitis media with sensory hearing loss and to compare the severity of sensorineural hearing loss in both types of chronic otitis media. We also aimed to study the correlation between sensorineural hearing loss and chronic otitis media.

The present study was conducted as a cross sectional observational study on patients with COM seeking care in the Department of Otorhinolaryngology (ENT), People’s College of Medical Science and Research centre  & associated People’s Hospital, Bhopal  during the study period of 18 months. All the individuals above the age of 10 years and below 55 years presenting with COM and willing to participate in the study were included whereas patients with ear surgery and head or ear trauma, family history of deafness, history of noise induced hearing loss, genetic disorders and known systemic illness (such as Diabetes mellitus, HIV, tuberculosis, renal disorders, presbycusis) were excluded from the study.

After obtaining ethical clearance from Institute’s ethical committee, all the patients with COM satisfying inclusion and exclusion criteria were selected and written consent was obtained from all of them. Using the proforma, detailed history was enquired and documented. Thorough ontological examination of both the ears was done as detailed in proforma. The examination included inspection of pinna, pre auricular region, post auricular region, and external auditory canal. Examination of tympanic membrane was also done. Microscopic and otoendoscopic examination of ear was also done and findings were recorded. Based upon the findings of history and examination, provisional diagnosis was established. Further tuning fork tests were done using tuning forks of 256, 512 and 1024 Hz and findings of Rinne’s test, Weber’s test and ABC was documented. Pure tone audiometry (PTA) was done and findings were documented. Type and severity of hearing loss was assessed based on tuning fork tests and pure tone audiometry.

Statistical analysis

Data was compiled using MsExcel and analysis was done using IBM SPSS software version 20. Categorical data was expressed as frequency and proportions whereas continuous data was expressed as mean and standard deviation or median and interquartile range. Association of type of hearing loss with type and severity of COM was done using chi square test. Continuous variables between two groups were analyzed using independent t test (normally distributed data) or Kruskall Wallis test (non normally distributed data). P value of less than 0.05 was considered statistically significant.

Table 2- Association of type of hearing loss with severity of chronic otitis media

We observed mild Sensorineural hearing loss in 3.4% ears with mucosal COM and 25.6% ears with squamosal COM. About 18.6% ears with squamosal COM had moderate SNHL 9.3% had moderately severe SNHL and 4.7% ears had severe or profound SNHL. However, mild, moderate, moderately severe and severe conductive hearing loss was observed in 11%, 52.5%, 12.7% and 2.5% ears with mucosal COM and 11.6%, 0.9%, 7% and 2.3% ears with squamosal COM. The observed association of severity of hearing loss with type of chronic otitis media was found to be statistically significant (p<0.05) (Table 2).

Chronic otitis media is among the major cause of acquired hearing loss. Depending upon the extent and severity of COM, hearing impairment may be observed in as high as 80% of patients with COM.[1] Although,  COM is associated with conductive hearing loss, approximately one fourth of the patients may experience sensorineural hearing loss.[6,7] The type and severity of hearing loss are influenced not only by the extent of the perforation in the pars tensa but also by other variables such as granulation tissue, mucus, adhesions, and tympanosclerosis.[5] In this study, we aimed to assess its association with type of COM. This study included 120 patients with COM, among them, 92 (76.7%) cases had mucosal COM and 28 (23.3%) cases had squamosal COM. 31 patients (25.8%) had bilateral COM whereas remaining patients had unilateral COM. 118 ears had mucosal COM and 43 ears had squamosal COM. Thus, 161 ears of 120 patients were studied.

Conductive hearing loss in cases of chronic otitis media (COM) is secondary to tympanic membrane perforation, ossicular chain disruption, and structural alterations in both the tympanic membrane and ossicles. Yen et al documented that the occurrence of SNHL is 3 times higher in COM patients as compared to control group (14.47 vs 4.83 per 10 000 person-years).[8] Sensorineural hearing loss occurs due to the extension of inflammation through the round window membrane in the middle ear cleft or the middle ear's involvement in the auditory mechanism via bone conduction, commonly known as Carhart's effect. Additionally, direct invasion of organisms in the inner ear can contribute of SNHL.[9]

In the present study, we observed conductive hearing loss 78.8% patients with mucosal COM and 41.9% cases with squamosal COM whereas sensorineural hearing loss was observed in 21.2% ears with mucosal COM and 58.1% ears with squamosal COM. With respect to severity, more than half of the patients with mucosal COM had moderate conductive loss (52.5%) whereas the majority of patients with squamosal COM had mild SNHL (25.6%).  We found incidence as well as severity of SNHL to be significantly higher in cases of squamosal COM as compared to mucosal COM (p<0.05). However, our study found no significant association of Pure tone audiometry in with types of COM in patients presenting with SNHL (p>0.05).

Jan et al defined SNHL as a statistically significant difference between the bone conduction thresholds of diseased ears and normal ears and the authors found significant component of SNHL in cases with CSOM. The authors suggested that SNHL is linked to CSOM and that the extent of hearing loss is statistically significant.[10] Sadasivan et al in their study on 378 patients with mucosal COM and 259 patients with squamosal COM documented SNHL in 7.93% and 11.58% cases respectively.[1] Further, our study findings were supported by the findings of Padmanabhan et al, where 12% patients with mucosal COM and 36% patients with squamosal COM had SNHL. The authors found a significant correlation of SNHL with duration of disease and presence of cholesteatoma (p<0.05). The patients had a greater BC threshold if they had a cholesteatoma. Prompt and effective treatment can reduce the frequency of this sequel as the degree of SNHL was observed to depend on the duration of the condition.[3]

Additionally, Moruskar et al reported mixed hearing loss in 18% patients with safe COM and  36% patients with unsafe COM.[12] Rana et al found earlier progression of SNHL in Squamosal disease as compared to mucosal disease.[13] Rajput et al reported SNHL in 19.5% patients with COM and the prevalence of SNHL was documented to be higher in patients with longer duration of COM, probably due to increase in severity of COM.[14] Chaudhary et al observed SNHL in 24% patients with COM and higher frequencies were affected in cases with SNHL.[15]

Tang et al observed significantly higher AC (P=0.000) and ABC gap in patients with cholesteatoma as compared to patients without cholesteatoma group, but the authors found no significant difference in BC between patients with and without cholesteatoma (p>0.05). Also, the authors found significantly higher severity of hearing loss in patients with cholesteatoma. The authors found presence of cholesteatoma to be protective against SNHL.[16] Gill et al reported SNHL in 13% cases with COM and they found a significant association with severity of SNHL and cochlear damage. A contributing component to this disease process may be aging. Furthermore, substandard living circumstances in lower socioeconomic groups contribute to both the development of CSOM and, to a lesser extent, the sensorineural hearing loss that CSOM patients experience.[4]

Nonetheless, a number of researchers have documented that sensorineural hearing loss (SNHL) can also occur concurrently with or as a sequalae of COM. According to several studies, patients with COM had an incidence of SNHL of up to 23%–24%.[6,7] Sensorineural hearing loss in cases with COM results either form extension of inflammation through the round window membrane in the middle ear cleft or the middle ear's role in the hearing mechanism through bone conduction, also referred to as Carhart's effect. It may also result from organisms directly invading the inner ear.[9] The round window and the nearby scala tympani may become inflamed as a result of chronic otitis media. This can lead to sensorineural hearing loss by reducing the area of the stria vascularis and causing the loss of both inner and outer hair cells in the basal turn. The spiral ligament fibrocytes, which produce chemokines in response to otitis media pathogens, specifically MCP-1/CCL2 (monocyte chemoattractant protein-1), have also been connected to the pathogeneses of inner ear inflammation in chronic otitis media.[17-19]

Additional COM-related cochlear damage may become more noticeable in later life due to the age-related decline in inner-ear function.[20-22] Apart from this, repeated use of ototoxic drugs or ear drops in cases with chronic otitis media may lead to increase in transfer of the drugs to inner ear through round window leading to otoxixity as well as sensorineural hearing loss.[18] Patients with COM attico-antral disease (AAD) are prone to labyrinthitis, which may be the cause of SNHL, due to the erosion of the otic capsule and exposure to labyrinth.[23]

Although the occurrence of SNHL in CSOM is proven, it remains unclear what causes neural deafness. According to Paparella, toxins travel via the round window membrane from the middle ear to the inner ear. Additionally, he noted inflammatory cells and serofibrinous precipitates in the inner ears close to the round window membrane.[24] Others, however, observed cochlear hydropsis, labyrinthitis, and inflammatory cell infiltration of the round window.[25]

The present study had certain limitations. Since this was a single facility based study with smaller sample size on homogeneous population, the findings of the study could not be generalized. Second, the study was conducted as a cross sectional study and outcome of patients and improvement in hearing following management of two types of COM could not be compared. Third, only tuning fork tests, otoendoscopy and pure tone audiometry was conducted in each patients, more sensitive investigations could not be done in all the patients.

Chronic otitis media (COM) is a common condition for which patients seek care at our ENT outpatient department. While conductive hearing loss is a hallmark of COM, sensorineural hearing loss (SNHL) of varying severity is also frequently observed. SNHL is more commonly associated with the squamous type of COM; however, some cases of mucosal COM may also exhibit this condition. This indicates that SNHL can develop due to either squamous or mucosal CSOM. Since the severity of SNHL has been found to correlate with squamosal COM, early and effective treatment can help minimize the risk of SNHL and its associated complications. Prompt intervention can lead to better disease prognosis, prevent progression, reduce complications, improve quality of life, and contribute to better public health outcomes. Conversely, delayed treatment may result in irreversible language deficits, academic difficulties, and social isolation. This study aims to facilitate the early identification and management of patients with sensorineural hearing loss in chronic otitis media, ultimately improving patient care and treatment outcomes.

1.       Sadasivan SS, Viswanatha B, Satish HS, Ravikumar R, Vijayashree MS, Datta RK, Dhanapala N. A comparative study of sensorineural hearing loss in mucosal and squamous type of chronic otitis media. Research in Otolaryngology. 2015;4(1):13-7.

2.       Kong K, Coates HL. Natural history, definitions, risk factors and burden of otitis media. Medical Journal of Australia. 2009 Nov;191(S9):S39-43.

3.       Jassar P, Murray P, Wabnitz D, Heldreich C. The posterior attic: An observational study of aboriginal Australians with chronic otitis media (COM) and a theory relating to the low incidence of cholesteatomatous otitis media versus the high rate of mucosal otitis media. International journal of pediatric otorhinolaryngology. 2006 Jul 1;70(7):1165-7.

4.       Gill AK, Divya A, Modwal A, Sharma MP. A study of sensory neural hearing(SNHL) loss in patients with chronic suppurative otitis media(CSOM). IOSR Journal of Dental and Medical Sciences (IOSR-JDMS). 2023 Jan. 22 (1); 37-46.

5.       Costa SS, Rosito LP, Dornelles C. Sensorineural hearing loss in patients with chronic otitis media. European Archives of Oto-Rhino-Laryngology. 2009 Feb;266:221-4.

6.       Kaur K, Sonkhya N, Bapna AS. Chronic suppurative otitis media and sensorineural hearing loss: Is there a correlation?. Indian journal of otolaryngology and Head and Neck surgery. 2003 Mar;55:21-4.

7.       Thakur CK, Gupta A, Kumar A. Does mucosal chronic otitis media leads to sensorineural hearing loss. Indian Journal of Otolaryngology and Head & Neck Surgery. 2019:1-3.

8.       Yen YC, Lin C, Weng SF, Lin YS. Higher risk of developing sudden sensorineural hearing loss in patients with chronic otitis media. JAMA Otolaryngology–Head & Neck Surgery. 2015 May 1;141(5):429-35.

9.       Islam MS, Islam MR, Bhuiyan MA, Rashid MS, Datta PG. Pattern and degree of hearing loss in chronic suppurative otitis media. Bangladesh journal of Otorhinolaryngology. 2010;16(2):96-105.

10.    Jan AI, Hussain MJ, ASLAM MJ. Sensorineural hearing loss in chronic suppurative otitis media. Pak J Med Health Sci. 2014;8(3):516-7.

11.    Padmanabhan D, Viswanatha B, Ramabhadraiah AK, Vijayashree MS, Killera S. Sensorineural Hearing Loss in Mucosal and Squamous Type of Chronic Otitis Media-A Prospective Study. Bangalore Medical College & Research Institute. 2017;6(1):6-9.

12.    Moruskar A., Karodpati N., Ingale M., Shah S. Study of pattern of hearing loss in CSOM (chronic suppurative OTITIS media). Ophthal Rev: Tro J ophtha & Oto. 2019;4(2): 131-6.

13.    Rana AK, Singh R, Upadhyay D, Prasad S. Chronic otitis media and its correlation with unilateral sensorineural hearing loss in a tertiary care centre of North India. Indian Journal of Otolaryngology and Head & Neck Surgery. 2019 Nov;71(Suppl 2):1580-5.

14.    Rajput MS, Rajput MS, Arain AA, Zaidi SS, Hatem A, Akram S. Mucosal type of chronic suppurative otitis media and the long-term impact on hearing loss. Cureus. 2020 Sep;12(9).

15.    Chaudhary K, Verma JK. Study of correlation between duration of chronic suppurative otitis media and sensorineural hearing loss. International Journal of Contemporary Medical Research 2021;8(3):C4-C6.

16.    Tang Y, Lian B, Zhang M, Tu X, Zhang T, Wang H. Sensorineural damage in chronic suppurative otitis media with and without cholesteatoma: a comparative study. Annals of Translational Medicine. 2022 Jul;10(14).

17.    MacArthur CJ, Hausman F, Kempton JB, Sautter N, Trune DR. Inner ear tissue remodeling and ion homeostasis gene alteration in murine chronic otitis media. Otology & Neurotology. 2013 Feb 1;34(2):338-46.

18.    Moon SK, Moon SK, Park R, Moon SK, Park R, Lee HY, Nam GJ, Cha K, Andalibi A, Lim DJ. Spiral ligament fibrocytes release chemokines in response to otitis media pathogens. Acta oto-laryngologica. 2006 Jan 1;126(6):564-9.

19.    Woo JI, Pan H, Oh S, Lim DJ, Moon SK. Spiral ligament fibrocyte-derived MCP-1/CCL2 contributes to inner ear inflammation secondary to nontypeable H. influenzae-induced otitis media. BMC infectious diseases. 2010 Dec;10:1-0.

20.    Jensen RG, Koch A, Homøe P. The risk of hearing loss in a population with a high prevalence of chronic suppurative otitis media. International Journal of Pediatric Otorhinolaryngology. 2013 Sep 1;77(9):1530-5.

21.    Avnstorp MB, Homøe P, Bjerregaard P, Jensen RG. Chronic suppurative otitis media, middle ear pathology and corresponding hearing loss in a cohort of Greenlandic children. International journal of pediatric otorhinolaryngology. 2016 Apr 1;83:148-53.

22.    Aarhus L, Homøe P, Engdahl B. Otitis media in childhood and disease in adulthood: a 40-year follow-up study. Ear and Hearing. 2020 Jan 1;41(1):67-71.

23.    Upadhyay P, Hiremath CS, Prasen Reddy KR.A study of sensory neural hearing loss inchronic suppurative otitis media. Int J Otorhinolaryngol Head Neck Surg2020;6:112-7.

24.    Paparella MM, Oda M, Hiraide F, Brady D. Pathology of sensorineural hearing loss in otitis media. Annals of Otology, Rhinology & Laryngology. 1972 Oct;81(5):632-47.

25.    Walby AP, Barrera A, Schuknecht HF. Cochlear pathology in chronic suppurative otitis media. Annals of Otology, Rhinology & Laryngology. 1983 Mar;92(2_suppl):3-19.