|Year : 1985 | Volume
| Issue : 4 | Page : 183-6
Sensorineural hearing loss in chronic otitis media--a statistical evaluation.
MV Kirtane, SN Merchant, AR Raje, SP Zantye, KL Shah
M V Kirtane
|How to cite this article:|
Kirtane M V, Merchant S N, Raje A R, Zantye S P, Shah K L. Sensorineural hearing loss in chronic otitis media--a statistical evaluation. J Postgrad Med 1985;31:183-6
|How to cite this URL:|
Kirtane M V, Merchant S N, Raje A R, Zantye S P, Shah K L. Sensorineural hearing loss in chronic otitis media--a statistical evaluation. J Postgrad Med [serial online] 1985 [cited 2020 Oct 27 ];31:183-6
Available from: https://www.jpgmonline.com/text.asp?1985/31/4/183/5385
It is well known that chronic otitis media (COM) disrupts the sound transformer mechanism of the middle ear, resulting in conductive hearing loss. The classically described audiometric profile of a case of COM consists of elevated air conduction (AC) thresholds with normal bone conduction (BC) thresholds. Paparella and his co-workers,,,,in a series of articles, with clinical and histopathological documentation, have drawn attention to the fact that quiet development of sensorineural hearing loss can occur concomittantly or as sequelae of otitis media. Such a notion that there may be a sensorineural component in the hearing loss in COM has not been fully appreciated. There have been a few articles documenting such hearing loss in the available literature. The problem has been mentioned by Bealesbut he has provided no concrete data in support. English et aland Moore and Bestanalysed the audiograms of their patients suffering from COM and concluded that sensorineural hearing loss can be a sequela of COM.
It has also been our clinical impression that our patients with COM often have cochlear dysfunction in the form of elevated BC thresholds. A retrospective biostatistical study was performed to verify the accuracy of this observation and to attempt to correlate such cochlear dysfunction to the type of COM.
MATERIAL AND METHODS
The audiometric profiles of 100 consecutive patients undergoing tympanoplastic surgery for chronic otitis media which satisfied the following criteria were.
(1) unilateral COM, both safe and unsafe varieties. (2) COM that did not follow trauma. (3) no previous ear surgery. (4) a normal opposite ear in each case, clinically, on otoscopy, and on audiometry.
The pre-operative mean BC threshold (average: 500 Hz to 4000 Hz) of the diseased ear was compared to that of the opposite normal ear in each patient. Bone conduction thresholds had been obtained after adequate contralateral masking, by qualified audiologists, using the same audiometer (ARPHI MK 700) for all patients. It was felt that use of the opposite normal ear for comparison constitutes a satisfactory control group. Known causes of sensorineural hearing loss such as hereditary deafness, noise induced hearing loss, presbyacusis and ototoxicity due to systemic drugs would not bias the results since these conditions cause essentially bilateral and often symmetrical cochlear dysfunction. Previous ear surgery or trauma to the diseased ear could have resulted in sensorineural hearing loss; hence the provision for excluding such patients from the data collection.
Of the 100 patients evaluated, there were 60 males and 40 females. Their ages ranged from 6 to 65 years (mean: 24 years). Fifty-seven suffered from safe COM (55: central perforation with or without ossicular problems; 2: adhesive otitis media) while 43 had unsafe QOM (38: cholesteatoma; 4: attico-antral granulations with posterosuperior quadrant retraction; 1: tuberculous otitis media). Most of the patients had long-standing otorrhoea of many years' duration. The results of the data analysis are presented in[Table 1]and[Table 2], which are self-explanatory.
The results of this study indicate that there is a definite sensorineural component to the hearing loss in cases of COM. Bone conduction in diseased ears is depressed to a statistically significant degree when compared to that in normal control ears. It is interesting to observe that this trend is equally evident in both unsafe and safe varieties of COM (p <0.01 in both varieties-see[Table 1]. Cholesteatomatous and attico-antral types of COM are called 'unsafe' because of their propensity to cause numerous complications including sensorineural deafness. Hence one might expect then sensorineural hearing loss to be greater in such ears than in 'safe' varieties of COM. As shown in[Table 2], this is not the case. There is no statistical difference between the sensorineural deafness produced by unsafe and safe types of COM. In other words, 'safe' type of COM is not safe with respect to hearing.
The selection criteria for cases in this study were carefully formulated so as to exclude other causes of sensorineural hearing loss from biasing the results. It is thus reasonable to assume that COM is indeed the etiologic factor responsible for the observed sensorineural hearing loss. Paparella et alhypothesized that the round window membrane permits toxic materials to enter the inner ear and biochemically alter the inner ear fluids, resulting in gradual end-organ dysfunction. There is a growing experimental, clinical and histopathological evidence to support this view. Various animal studies have conclusively demonstrated the ability of this membrane to serve as a portal.Radioactive isotopes, labelled proteins, antibiotics, toxins and tracers have been placed on the middle ear surface of the round window membrane and later collected from perilymphatic fluids.Temporal bone sections from patients with otitis mediahave shown serofibrinous precipitate and inflammatory cells mainly localised in the scala tympani near the round window membrane.
In the light of these findings, it is pertinent to reconsider the question: "How safe is a draining ear?" and specially, "How safe is a 'safe' variety of COM?" The classic extra and intra-cranial complications of unsafe COM are well known and consequently early surgery for such ears is advocated. On the other hand, it has been traditionally assumed that a 'safe' type of COM (central perforation) is relatively harmless except for intermittent otorrhoea and conductive hearing loss. The documentation of insidious cochlear damage by even such a safe process is a rebuff to such a complacent attitude. Furthermore, it has been shown that the severity of sensorineural hearing loss increases with increasing duration of the disease.In our country, where there is high prevalence of COM in young children, the potential hazards of such cumulative sensorineural hearing loss in terms of language and educational impairment are obvious. It thus behaves the ENT surgeon to implement early medical and surgical management for all varieties of COM.
It has been said that deafness, in terms of social handicap, should be equated with blindness. Several blindness prevention and treatment programmes are being implemented in our country. Similar campaigns for the early diagnosis, prevention and treatment of deafness are also needed, more so because COM afflicts children the most. We estimate that more than a third of the children attending the school clinic at our hospital suffer from COM, many of them bilaterally. Each child is a potential candidate for the development of sensorineural hearing loss. It is felt that deafness prevention programmes should be initiated right at school age, at city, state and national levels, to combat this incapacitating handicap.
We are grateful to Dr. G. B. Parulkar, Dean, Seth G.S. Medical College and K.E.M. Hospital for permission to publish the hospital data.
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|2||English, G. M., Northern, J. L. and Fria, T. J.: Chronic otitis media as a cause of sensorineural hearing loss. Arch. Otolaryngol., 98: 18-22, 1973.|
|3||Moore, D. C. and Best, G. F.: A sensorineural component in chronic otitis media. Laryngoscope, 90: 1360-1366, 1980.|
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|5||Paparella, M. M., Brady, D. R. and Hoel, R.: Sensorineural hearing loss in chronic otitis media and mastoiditis. Trans. Amer. Acad. Ophthalmol. Otolaryngol., 74: 108-115, 1970.|
|6||Paparella, M. M., Oda, M., Hiraide, F and Brady, D.: Pathology of sensorineural hearing loss in otitis media. Ann. Otol. Rhinol. Laryngol. 81: 632-647, 1972.|
|7||Schachern, P. A., Paparella, M. M., Duvall, A. J. and Choo, Y. B.: The human round window membrane: an electron microscopic study. Arch. Otolaryngol., 110: 15-21, 1984.|