~Iain Articl~
DETERMINANTS OF SENSORINEURAL HEARING LOSS IN CHRONIC MIDDLE-EAR DISEASE Neeraj Kasliwal ~, Sanjeev Joshi 2 S.M. P a r e e k 3
Key words : Chronic Suppurative Otitis Media, Sensory Neural Hearing Loss.
INTRODUCTION Chronic middle ear disease especially chronic suppurative otitis media (CSOM) is a major public health problem in developing countries. It usually leads to a significant hearing impairment, sensorineural~2 hearing loss being one of them. An estimated 2/3rd of the w o r l d ' s hearing impaired population is believed to be distributed among developing countries with a greater proportion being of infective etiology. A considerable difference in the prevalence rate for ear disease is evident between developed countries and developing countries. Some of the reasons for this disparity are over-crowding, poor hygiene, poor nutrition, passive smoking, high rates of nasopharyngeal colonization with potentially pathogenic bacteria, ignorance, inadequate and unavailable health care. A tale estimate of the problem of deafness is not known in India. Various workers and o r g a n i z a t i o n s h a v e r e p o r t e d p r e v a l e n c e of hearing impairment in about 10% of ruraP 9 and 6.8% of urban ~ populations. A survey conducted by indian Council of Medical Research ~s has reported that the major aetiological factor responsible for hearing loss in rural areas is chronic suppurative otitis media (42.4%). In urban areas it is responsible for 23.1% of all cases of deafness.
non-intact tympanic m e m b r a n e (e.g. perforation) and discharge are present. The condition is widely prevalent worldwide. Studies have reported a high prevalence in certain populations in North America ~, and moderately high rates in certain natives of South Pacific Island 5. Various studies show prevalence of chronic suppurative otitis media in India to range from 2 to 15 %. In a study by Bluestone 2, India was considered to have a low prevalence area of 2% while a study from Haryana by Verma 20 reported it as high as 15.3%.
Chronic suppurative otitis media is a stage of ear disease in which there is chronic infection of middle ear cleft i.e. Eustachian tube, middle ear and mastoid and in which a
Therefore, in view of the magnitude of the problem in a developing country like India we retrospectively analyzed data from a referral centre in North India over a period of
The role of the r o u n d w i n d o w m e m b r a n e in the determination of sensorineural hearing loss in cases of chronic suppurative otitis media has been examined by various scientists 6. ~3,~5-~7,21,22. Round window membrane is a semipermeable membrane, which allows some substances like toxic materials to pass and cause biochemical changes in perilymph and endolymph causing destruction of organ of Corti ~7. It has been o b s e r v e d that the p a s s a g e of macromolecules such as proteins in the perilymph is favoured during inflammation of middle ear, dependent probably on an increase in vessel permeability (Hache et al, 1969) 7.
Consultant, Dr KC Kasliwal's ENT Centre, Jaipur, 2 Asst. Professor,Mahatma Gandhi National Institute of Medical Sciences, Jaipur, 3 Consultant, Hospital Kualaterenganu, Malaysia.
270
Determinats of Sensorineurat Hearing Loss in Chronic Middle-Ear Disease
two decades from 1982 to 2001 to determine determinants of sensorineural deafness in patients with CSOM. The study was done to emphasize the need for regular assessment of sensorineural e l e m e n t in patients with C S O M . It is recommended that when this condition is diagnosed, active surgical or medical treatment should be started to obviate the sensorineural hearing handicap.
METHODS The study group consisted of 1828 patients who underwent surgery at our centre for chronic suppurative otitis media from the year 1982 to 2001, out of which 510 cases were selected who met the following criteria. 9
9 9 9 9
Unilateral chronic suppurative otitis media (normal tympanic membrane in contralateral ear). This normal contralateral ear served as an excellent control because it eliminated variables such as noise, hereditary or congenital causes & presbyacusis. No history of head injury. No history of previous ear surgery involving bone drilling. No history of meningitis and No history of systemic disease that might affect hearing.
All the patients underwent complete clinical examination. Pure tone audiometry was performed by a calibrated audiometer in a sound-proof room and nalTow band masking was used when appropriate. Sub groups of patients were analysed on the basis of duration of disease, presence or absence of otorrhea, site and size of perforation, presence or absence of cholesteatoma, intact or eroded ossicular chain and their relationship to the degree of sensorineural hearing loss at five test frequencies. Otorrhea was defined as presence of ear discharge at the time of diagnosis. Perforation was either central or marginal. Central perforation is further subdivided into small if only one quadrant of tympanic membrane is involved, medium if two quadrants are involved, large if three quadrants are involved and subtotal if all four quadrants are involved by the perforation. Cholesteatoma was either present or absent and ossicular chain was either intact or eroded e.g. absent Lenticular process of Incus. Statistical analysis: Differences in bone threshold in diseased ears and control ears at five test frequencies (250HZ, 500HZ, IKHZ, 2KHZ, 3KHZ & 4KHZ) were analysed. All the data were computerized and analysed using SPSS Version 4.0.1
(SPSS Inc., USA) statistical package. The ordinal variables are reported as percent and n u m e r i c a l v a r i a b l e s as mean+lSD. Inter-frequency comparison was performed using t-test or ANOVA as appropriate. P value <0.05 was considered significant.
RESULTS Of the 510 patients studied, 290 (56.8%) were male and 220 (43.2%) were female. Age ranged from 4 years to 63 years with a median of 35 years. The disease was in 254 (49.8%) right and 256 (50.2%) left ears. Thus male to female ratio and side of the ear affected were the same. Table I : Demographic Characteristics of the Study Subjects (n = 510) Variables Age - distribution (years) 0-9 10-19 20-29 30-39 40-49 50-5960+ Gender Male Female Diseased ear Right Left Disease duration (years) <1 2-5 6-10 11-15 >15 Otorrhoea status Dry Wet Perforation site/size Attic Central-Small Central-Medium Central- Large Sub-total Cholesteatoma Absent Present Ossicular chain status Intact Eroded Not known
Indian Journal off Otolaryngology and Head and Neck Sucwrv, Vol. 56, No. 4, October - December. 2004
Numbers (%) 27 (5.3) 185 (36.3) 150 (29.4) 93 (18.2) 42 (8.2) 10 (2.0) 3 (0.6) 290 (56.8) 220 (43.2) 254 (49.8) 256 (50.2) 143 (28.0) 176 (34.5) 75 (14.7) 53 (10.4) 63 (12.4) 126 (24.7) 384 (75.3) 205 (40.2) 54 (10.6) 106 (20.8) 104 (20.4) 41 (8.0) 264 (51.6) 246 (48.4) 26l (51.2) 242 (47.4) 7 (1.4)
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Determinats of Sensorineural Hearing Loss in Chronic M~ddle-Ear Disease
Table l shows the d e m o g r a p h i c profile of the study population of 510 cases. Maximum subjects were in age group 10 to 30 years, thus a majority of patients suffering from this disease were young. The disease was of short duration i.e. patients presented early in the course of disease with maximum number of patients presenting within first five y e a r s of the onset of disease. The ears were predominantly wet at the time of diagnosis. 40% patients had marginal perforation. Rest of the patients had central perforation, out of which 210 (41.2%) were having medium to large perforations. The incidence of presence or absence of cholesteatoma and intact and eroded ossicular chain was almost equal.
Table II : Comparison of bone conduction thresholds in diseased and non-diseased ears (n=510)
Frequencies
Normal
Diseased
p-value
250
12.2_+5.5
12.8_+7.7
0.343
500
9.22_+7.0
9.80_+9.6
0.271
1000
8.41_+7.1
9.11_+9.5
0.183
2000
9.06_+7.6
11.58_+10.1
<0.001
4000
15.19_+8.1
17.64_+10.3
<0.001
Table II compares the bone conduction threshold i.e. SNHL between diseased and control ears. This was found to be significant at higher frequencies i.e. 2KHz and 4KHz.
Table III : Duration of disease and bone conduction threshold difference in diseased and non-diseased ears Frequencies
Duration of Disease (years)
2-5
<1 250
-0.42•
1.50_+7.0
1.13_+8.5
500
-0.46•
0.888.5
1.20•
1000
-0.56_+8.0
0.59_+7.6
2000
2.38_+9.3
4000
1.81_+8.4
11-15
6-10
1.50•
>15
P value ANOVA test)
3.20_+7.2
<0. 001
0.47•
2.60•
0.002
2.20_+10.7
1.32_+10.2
2.10_+9.6
0.006
3.01_+8.8
3.13•
2.54_+11.0
1.34_+8.1
0.038
3.01_+10.2
2.67_+13.1
3.3_+8.7
3.66_+11.5
0.058
Table III shows a significant co-relation between duration of the disease and SNHL in diseased ears as compared to normal ears especially at lower frequencies. Table IV: Type of disease and Bone Conduction threshold difference in Diseased and Non-diseased Ears
Frequ- Otorrhoea Status encies
~holesteatoma
Ossicular Chain
Site of Perforation
Eroded
Intact
A*
S
1.57_+8.3 0.34+6.6*
1.96_+8.4'
0.06+6.6
1.46_+7.4
0.28_+7.2
-0.14_+7.9 0.04+7.0
4.63_+9.4
0.05_+9.1'
1.39_+9.4 -0.22+8.8*
1.55_+9.5'
-0.05_+8.4
1.41_+9.1
-0.93_+9.1
-0.14_+7.9 -0.34+9.0
2.56+11.8
0.32+9.1
0.83-+8.5
1.54-+9.3
-0.22+7.9*
1.83_+9.2'
-0.44_+7.9
1.32_+8.7
-1.67_+8.8
-0.19-+7.0
3.53+10.4
2000
2.14+9.9
2.64_+9.3
4.25_+10.2 0.99+8.5*
4.82_+10.5'
0.79_+7.9
4.31_+9.7
0.28_+9.7
0.71+_7.9 1.49+9.8
4000
2.34+8.9
2.42_+11.1 3.50-+11.5 1.37+9.5'
3.78_+11.8'
1.32_+9.2 3.12_+115
2.22_+8.7
1.42+7.7 2.16+11.9 2.80_+10.9
Dry
Wet
250
0.56_+7.9
1.12_+7.5
500
1.33+9.1
1000
Yes
No
M
L
0.53+8.9
ST*
3.8+9.3
9p<0.05
In Table IV, it is observed that there is a significant corelation between presence of cholesteatoma and erosion of ossicular chain with SNHL, at all frequencies. Similarly Table IV showed greater loss in bone conduction threshold in subtotal and attic perforations, which is statistically significant at speech frequencies.
As it is evident from Table IV, there is not much statistical significance of status of otorrhea causing SNHL. DISCUSSION In developing countries such as India people ignore ear disease (particularly discharging ear) due to many reasons
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Determinats of Sensorineural Hearing Loss in Chronic Middle-Ear Disease
such as illiteracy, poverty, lack of knowledge, insufficient provision of health services etc. We have observed definite and significant correlation between duration of disease (chronic suppurative otitis media) and sensorineural hearing loss. Chronic suppurative otitis media is a common source of morbidity in rural India. It is the most important cause of deafness in India and occupies a considerable amount of clinic and operating time of Otolaryngologist. The present study was u n d e r t a k e n to e x a m i n e the presence of sensorineural hearing loss in chronic suppurative otitis media.
ossicular chain. Though the higher frequencies are more affected than the lower frequencies, but in subtotal and attic perforations the speech frequencies seemed to be maximally affected. Thus it is emphasized that the cases of chronic suppurative otitis media should be diagnosed early, by increasing awareness amongst people and managed effectively so as to prevent the chances of developing sensorineural hearing loss. REFERENCES 1.
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CONCLUSIONS This study shows presence of significant sensorineural heating loss in patients with chronic suppurative otitis media. Factors associated with greater hearing loss are duration of disease, presence of cholesteatoma and bony erosion of
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Indian Journal of Otolaryngology and Head and Neck Surgery, Vol. 56, No. 4, October - December, 2004
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Address for Correspondence : Dr KC Kasliwal's ENT Centre, Paanch Batti, Jaipur 302001 India. E-mail: drnkasliwal @hotmail.com
