Indian Journal of Public Health

SHORT COMMUNICATION
Year
: 2011  |  Volume : 55  |  Issue : 2  |  Page : 132--134

Prevalence of hearing impairement in the district of Lucknow, India


Anupam Mishra1, Veerendra Verma1, Girish Kumar Shukla2, Subhash Chandra Mishra2, Raghav Dwivedi3,  
1 Associate Professor, Department of Otolaryngology and Head and Neck Surgery, King George's Medical College (CSMMU), Lucknow, India
2 Professor, Department of Otolaryngology and Head and Neck Surgery, King George's Medical College (CSMMU), Lucknow, India
3 Senior Resident, Department of Otolaryngology and Head and Neck Surgery, King George's Medical College (CSMMU), Lucknow, India

Correspondence Address:
Anupam Mishra
Associate Professor, Department of Otolaryngology and Head and Neck Surgery, King George«SQ»s Medical College (CSMMU), Lucknow
India

Abstract

A multi-cluster study (survey) was carried out by department of ENT KG Medical University, Lucknow from July 2003 to August 2004 in rural and urban population of Lucknow district to estimate prevalence and causes of hearing impairment in the community. Data included audiological profile and basic ear examination that was analysed through EARFORM software program of WHO. Overall hearing impairment was seen in 15.14% of rural as opposed to 5.9% of urban population. A higher prevalence of disabling hearing impairment (DHI) in elderly and deafness in 0-10 years age group was seen. The prevalence of sensorineural deafness necessitating hearing aids was 20% in rural and 50% in urban areas respectively. The presence of DHI was seen in 1/2 urban subjects and 1/3rd of rural counterparts. The incidence of cerumen / debris was very common in both types of population and the need of surgery was much more amongst rural subjects indicating more advanced / dangerous ear disease.



How to cite this article:
Mishra A, Verma V, Shukla GK, Mishra SC, Dwivedi R. Prevalence of hearing impairement in the district of Lucknow, India.Indian J Public Health 2011;55:132-134


How to cite this URL:
Mishra A, Verma V, Shukla GK, Mishra SC, Dwivedi R. Prevalence of hearing impairement in the district of Lucknow, India. Indian J Public Health [serial online] 2011 [cited 2020 Sep 29 ];55:132-134
Available from: http://www.ijph.in/text.asp?2011/55/2/132/85251


Full Text

Data regarding magnitude of hearing impairment in urban and rural population in our country is limited. The present epidemiological study primarily aims to estimate the prevalence of hearing impairment and their cause both in urban and rural communities in the district of Lucknow.

This epidemiological study (survey) was conducted using cluster-sampling technique for both rural and urban sites as per World Health Organisation (WHO) criteria [1] in Lucknow district from July 2003 to August 2004. The population of 6 months of age and above was included in the survey carried out by the department of Otolaryngology, KG Medical College, Lucknow, India.

Based on earlier studies and available literature, the prevalence of hearing impairment was found to vary from 5% to 17% in the district of Lucknow and in different parts of India. Assuming an average prevalence of 10%, sampling error 11%, 95% confidence interval with design effect 2, the sample size was calculated to be 6892. Considering 5% non-response, the total sample size required was 7237 in rural and urban areas separately. Following 30 cluster methodology the target population of 241 subjects per cluster was desirable. The households were selected randomly from each cluster. Villages in the rural areas of the district of Lucknow and urban-blocks in the Lucknow city constituted the clusters.

The survey of total 14650 subjects was carried out 2-3 days a week from 9.00 AM to 5.00 PM. Each cluster was tried to cover in at least 2 visits. In case, it was not possible to collect data from all the targeted family members of a cluster in 2 visits, a 3 rd visit was undertaken to include missing subject/s. The objectives of the survey were explained to the community involving community leaders and as to how it would be beneficial to them. Further assurance was given to maintain confidentiality of the surveyed subjects and not to disclose their information to any other organization / institution without their consent. During the survey the selection team from a central prominent point in a cluster, randomly selected a direction and then proceeded to select the nearest household. Thereafter every 2 nd to 5 th households (depending upon the number of households in a cluster) were surveyed.

A team of experts including ENT specialists, epidemiologists, statisticians and social scientists had trained all members of the survey team. They were told about the objectives of the study and as to how different parameters need to be measured. The female and male workers both were included in the survey team that was in turn lead by a junior consultant (faculty) of ENT. The survey team consisted of one ENT consultant, one audiologist (same throughout the study), and 2 social workers (same throughout the study). Notably the same audiometer and sound level meter was used in the entire study with due emphasis on calibrating the audiometer. Care was taken to maintain the quality of information collected and thus to minimize the non-sampling errors such as inadequately calibrated instrument, observer variation, incomplete coverage achieved in examining the subjects, conceptual errors etc. ENT consultants of the rank of assistant professor were fully responsible for the patient diagnosis with history and examination based on strict / established criteria. The survey members were given instructions from time to time during survey and examinations. A formal one week training before the onset of survey was conducted to educate all the team members regarding the details of protocol, standardize the methodology and finalise the survey instruments. Hands-on-experience was given to the social workers by ENT consultants.

The major details recorded were degree and causes of deafness, along with basic ear assessment. After registration of the subject, the hearing status was assessed by behavioural observation in less than 4 years and by pure tone audiometry (PTA) in subjects over 4 years of age. The same audiologist measured / documented subjective responses and the same audiometer was used through out the study. For behavioural assessment amongst children (6 months to 4 yrs age), a simple question was asked from at least ΍ meter in normal conversation voice. A positive response either by turning or showing attention was recorded as 'YES'. In PTA only air conduction (AC) thresholds (0.5 KHz, 1 KHz, 2 KHz, 4 KHz) were measured inside a local sound-restricted chamber with ambient noises of <30 dB. Efforts were made to calibrate the audiometer every 3 weeks. An effort was made to carry out otoacoustic emission screening in all the paediatric cases below 4 years showing suspicious deafness. Such a suspicion was concluded by doubtful 'YES' response or by abnormality of tympanic membrane. All those children less than 4 years age showing abnormal OAE ('Fail' criteria) were considered to have disabling hearing impairment but for estimating hearing levels amongst older children, behavioural assessment with pure tone audiometry was considered. Following hearing assessment the subjects underwent ear examination by ENT consultant followed by a brief interview. The examination focused on basic ear assessment including earache, auricular deformity, external ear examination for wax, pus foreign body, fungus or inflammation; ear drum abnormalities (retraction, bulging, perforation, inflammation); and middle ear status (pus, granulations, cholesteatoma). Enquiry regarding the duration of hearing impairment and a family history of hearing impairment was recorded. The causes of hearing impairment were concluded as being secondary to ear disease, systemic infectious disease, genetic conditions, or nonspecific / indeterminate cause. Finally a proper consultation and information was provided along with medication and referral to KG Medical College, Lucknow. It is worth mentioning that despite the presence of occluding wax / foreign body / pus, pure tone audiometry was performed without removing it. The abnormal hearing status was categorized as either 'hearing impairment' or 'disabling hearing impairment'. 'Hearing-Impairment' was said to exist if average PTA threshold was > 25 dB, while 'Disabling-Hearing-Impairment' was defined as average PTA threshold of 41dB and above in those greater than 15 years of age and 31 dB or more for ages 4-15 years. Data was entered in a computer software program called EARFORM developed as a part of WHO protocol and was used for analysis.

The overall hearing impairment was seen in 15.10% in rural population and in 5.9% of urban population in Lucknow district. It is worth noting that 1/3 rd of rural subjects and nearly half of urban subjects with abnormal hearing showed disabling hearing impairment. The disabling hearing impairment in elderly was markedly lower in urban areas as compared to rural, 47% and 65% respectively. 5.4% of children < 10 years showed disabling deafness. Also the prevalence of disabling hearing impairment in urban children less than 10 years was much less as compared to rural counterparts (1.2% and 5.4% respectively). The prevalence of bilateral hearing impairment was in general more common than unilateral deafness, and this was more marked in urban population.

The most common reversible cause of hearing impairment was presence of cerumen / debris (th + fungal) in either ear (2.1% in both rural and urban), followed by chronic suppurative otitis media in either ear (1.1% in rural vs. 0.5% in urban) and dry perforation of tympanic membrane in either ear (0.8% rural vs. 0.4% urban). However sensorineural hearing loss dominated as the most common type of irreversible hearing impairment. It is worth mentioning that presumptive diagnosis of serous otitis media and presbyacusis was made.

The need for medication predominantly in the form of either wax-solvent eardrops or antibiotic preparations (topical / systemic) with or without antifungal eardrops was seen in 10.1% in rural population and 6.4% in urban population. The need for hearing amplification device was similar in both population (2.9% in rural and 2.7% in urban).

The study reveals difference in prevalence of hearing impairment amongst rural and urban population. The disabling hearing impairment in elderly is less common in urban areas probably due to a better access to ear care. The prevalence of disabling hearing impairment in Lucknow has been reported to be 10.8% in urban and 11.4% in rural in WHO publication. [2] The higher prevalence of deafness in 0-10 years age group amongst rural population possibly reflects a higher prevalence of serous otitis media and chronic suppurative otitis media. The sensorineural hearing loss including ototoxic- / noise-induced- damage, and presbyacusis showed higher prevalence in rural than urban population but an overall similar need for hearing aids. Of all those with hearing loss, the prevalence of sensorineural deafness necessitating hearing aids was 20% in rural population and 50% amongst urban population. The presence of disabling hearing impairment in 1/2 urban subjects with hearing loss in contrast to 1/3 rd of rural counterparts may be due to the contribution of traffic / industrial noise-induced hearing loss in day to day urban life. The more commonly encountered conductive hearing impairment resulting from otitis media in rural set-up may be due to poor access to proper medication / advice and also due to inappropriate prevalent practices such as using crude plant extract / boiling liquids and oils in a discharging ear. The incidence of cerumen / debris is very common in both types of population but the inappropriate extraction (of cerumen/ foreign body) by indigenous practitioners / quacks predispose to tympanic membrane trauma or external otitis leading to hearing impairment specially in rural areas. The necessity of surgery for ear disease was much more amongst rural subjects indicating more advanced / dangerous disease-stage as compared to their urban counterparts.

Since 80% of rural and 50% of urban hearing-impaired-population has been found to have predominantly conductive hearing impairment or early / mild sensorineural loss, an early intervention and quality patient education is necessary for prevention of hearing impairment in majority of cases.

The authors duly acknowledge the financial and technical support of World Health Organisation for conducting the study.

References

1Bennett S, Woods T, Liyanage WM, Smith DL. A simplified general method for cluster-sample surveys of health in developing countries. World Health Stat Q 1991;44:98-106.
2Mathers C, Smith A, Concha M. Global burden of hearing loss in the year 2000. Geneva, World Health Organisation (WHO). Available from: http://www.who.int/healthinfo/statistics/bod_hearingloss.pdf. [Last accessed on 2009 Feb 15].