Prevalence and causes of hearing impairment in Fundong Health District, North-West Cameroon

Hearing health survey of the population in Bangkok

In this cross-sectional random survey among Thai adults living in Bangkok, we aimed to identify the prevalence of hearing problems and examine their relationship with individual factors. We administered a self-report questionnaire and performed pure-tone air conduction threshold audiometry. A total of 2463 participants (1728 female individuals) aged 15-96 years were included. The hearing loss prevalence was 53.02% and increased with age. The prevalence of a moderate or greater degree of hearing impairment was 2.8%. Participants aged 65 years and over had 8.56 and 6.79 times greater hearing loss and hearing impairment than younger participants, respectively. Male participants were twice as likely to have hearing loss and hearing impairment as female individuals. Participants with higher education levels showed less likelihood of having hearing loss and hearing impairment than those with no or a primary school education. Participants who ever worked under conditions with loud noise for > 8 h per day had 1.56 times greater hearing loss than those without such exposure. An inconsistent correlation was found between hearing loss, hearing impairment and noncommunicable diseases (diabetes, hypertension, and obesity). Although most participants had mild hearing loss, appropriate care and monitoring are necessary to prevent further loss in such individuals. The questionnaire-based survey found only people with hearing problems that affect daily communication.

Evaluating the inclusion of tympanometry in population-based surveys of hearing loss

Objective

This study aimed to determine the implications of including tympanometry in the Rapid Assessment of Hearing Loss survey protocol. A comparative study design was employed, with findings from otoscopy compared with the results of tympanometry.

Method

A population-based survey of the prevalence and causes of hearing loss among adults aged over 35 years in The Gambia was conducted. Clinical assessments included air conduction audiometry, otoscopy and clinical history. Otoscopy outcome was recorded and for those with hearing loss, a probable cause was assigned. Following otoscopy, tympanometry was completed. Otoscopy outcome was not changed as a result of tympanometry. Clinician assigned cause was compared to the results of tympanometry. The proportion of causes potentially misclassified by excluding tympanometry was determined.

Results

Among people with hearing loss, including tympanometry led to a higher proportion diagnosed with middle-ear conditions.

Conclusion

The value of adding tympanometry to population-based survey protocols is a higher estimated proportion of hearing loss being attributed to middle-ear disease rather than sensorineural causes. This can inform service needs as more people will be classified as needing medical or surgical services, and a slightly lower number will need rehabilitative services, such as hearing assistive devices. It is highly recommended that tympanometry is included in the protocol.

Exploring the Use of Washington Group Questions to Identify People with Clinical Impairments Who Need Services including Assistive Products: Results from Five Population-Based Surveys

This study analyses the use of the self-reported Washington Group (WG) question sets as a first stage screening to identify people with clinical impairments, service and assistive product (AP) referral needs using different cut-off levels in four functional domains (vision, hearing, mobility and cognition). Secondary data analysis was undertaken using population-based survey data from five countries, including one national survey (The Gambia) and four regional/district surveys (Cameroon, Chile, India and Turkey). In total 19,951 participants were sampled (range 538–9188 in individual studies). The WG question sets on functioning were completed for all participants alongside clinical impairment assessments/questionnaires. Using the WG “some/worse difficulty” cut-off identified people with mild/worse impairments with variable sensitivity (44–79%) and specificity (73–92%) in three of the domains. At least 64% and 60% of people with mild/worse impairments who required referral for surgical/medical and rehabilitation/AP services, respectively, self-reported “some/worse difficulty”, and much fewer reported “a lot/worse difficulty.” For moderate/worse impairment, both screening cut-offs improved identification of service/AP need, but a smaller proportion of people with need were identified. In conclusion, WG questions could be used as a first-stage screening option to identify people with impairment and referral needs, but only with moderate sensitivity and specificity.

Cost-Effectiveness of Hearing Screening in Older Adults: A Scoping Review

OBJECTIVES

Age is the most common predictor of hearing loss; however, many older adults are not screened. Hearing screening could improve healthcare access, participation, and outcomes. Establishing whether hearing screening in older adults is cost-effective could improve the availability and utilization of screening.

METHODS

We searched nine databases in January 2020. Studies with populations aged 50+ and provided data on the cost-effectiveness of hearing screening were included in the review.

RESULTS

Five studies met the inclusion criteria and all found hearing screening programs to be cost-effective compared to no hearing screening, regardless of screening method (i.e., instrument or strategy). The maximum number of repeated screenings, coupled with younger ages, was most cost-effective.

DISCUSSION

This review suggests that hearing screening in older adults is cost-effective, however, the evidence is limited. There is pressing need for research focused on economic impacts of hearing healthcare in older adults to inform research, policy and practice.

The use of the Washington Group on Disability Statistics questionnaires to identify hearing disability: a systematic review

PURPOSE

To investigate the use of instruments from the Washington Group on Disability Statistics (WG) to obtain data on hearing disability (HD).

RESEARCH STRATEGIES

We conducted searches in the PubMed, Scopus, Science Direct, Web of Science, Lilacs databases and the grey literature. The software "The State of the Art through Systematic Review" and "Mendeley" were used to assist in the bibliographic reference organization, selection, and storage.

SELECTION CRITERIA

we followed the guidelines proposed by the "Preferred Reporting Items for Systematic Reviews and Meta-Analysis" and we selected studies that met the following inclusion criteria: written in English or Portuguese, within the period of 2001 to 2017 and have used the WG hearing disability question.

DATA ANALYSIS

The variables analyzed into the studies were: WG module, country and year of data collection, sample size and composition, objective of the study, publication journal, HD estimate of prevalence and accuracy measures.

RESULTS

Sixty-five studies are included in the review, conducted with data from 30 countries. The WG Short Set of question was the most often used. Hearing disability prevalence ranged from 0.2 to 2.3% and only three studies estimated the accuracy of the instrument to identify HD.

CONCLUSION

The hearing disability question of WG has been used worldwide and mainly in developing countries. The short variation in the estimated prevalence measurements within studies seems favorable to the WG's goal of generate estimates that allow international comparison. However, the shortage of validity studies indicates the need for further investigations with this purpose.

Estimating assistive product need in Cameroon and India: results of population-based surveys and comparison of self-report and clinical impairment assessment approaches

OBJECTIVES

To estimate population need and coverage for distance glasses, hearing aids and wheelchairs in India and Cameroon, and to explore the relationship between assistive product (AP) need measured through self-report and clinical impairment assessment.

METHODS

Population-based surveys of approximately 4000 people each were conducted in Mahabubnagar district, India and Fundong district, Cameroon. Participants underwent standardised vision, hearing and musculoskeletal impairment assessment to assess need for distance glasses, hearing aids, wheelchairs. Participants with moderate or worse impairment and/or self-reported difficulties in functioning were also asked about their self-reported AP need.

RESULTS

6.5% (95% CI 5.4-7.9) in India and 1.9% (95% CI 1.5-2.4) in Cameroon of the population needed at least one of the three APs based on moderate or worse impairments. Total need was highest for distance glasses [3.7% (95% CI 2.8-4.7) India; 0.8% (95% CI 0.5-1.1), Cameroon] and lowest for wheelchairs (0.1% both settings; 95% CI 0.03-0.3 India, 95% CI 0.04-0.3 Cameroon). Coverage for each AP was below 40%, except for distance glasses in India, where it was 87% (95% CI 77.1-93.0). The agreement between self-report and clinical impairment assessment of AP need was poor. For instance, in India, 60% of people identified through clinical assessment as needing distance glasses did not self-report a need. Conversely, in India, 75% of people who self-reported needing distance glasses did not require one based on clinical impairment assessment.

CONCLUSIONS

There is high need and low coverage of three APs in two low-and middle-income settings. Methodological shortcomings highlight the need for improved survey methods compatible with the international classification of functioning, disability and health to estimate population-level need for AP and related services to inform advocacy and planning.

Field test of the Rapid Assessment of Hearing Loss survey protocol in Ntcheu district, Malawi

Objective: (1) To test the feasibility of the Rapid Assessment of Hearing Loss (RAHL) survey protocol in Malawi (Ntcheu); (2) To estimate the prevalence and probable causes of hearing loss (adults 50+).Design: Cross-sectional population-based survey.Study sample: Clusters (n = 38) were selected using probability-proportionate-to-size-sampling. Within each cluster, 30 people aged 50+ were selected using compact-segment-sampling. All participants completed smartphone-based audiometry (hearTest). Prevalence was estimated using WHO definitions (PTA of thresholds 0.5, 1, 2, 4 kHz in the better ear of >25 dB HL (any) and >40 dB HL (≥moderate)). Otoscopy and questionnaire were used to assess probable causes. Participants with hearing loss and/or ear disease were asked about care-seeking and barriers.Results: Four teams completed the survey in 24 days. 1080 of 1153 (93.7%) participants were examined. The median time to complete the protocol was 24 min/participant. Prevalence of hearing loss was 35.9% (95% CI = 31.6-40.2) (any level); and 10.0% (95% CI = 7.9-12.5) (≥moderate). The majority was classified as probable sensorineural. Nearly one third of people (30.9%) needed diagnostic audiology services and possible hearing aid fitting. Hearing aid coverage was <1%. Lack of perceived need was a key barrier.Conclusion: The RAHL is simple, fast and provides information about the magnitude and probable causes of hearing loss to plan services.

Field-testing of a rapid survey method to assess the prevalence and causes of hearing loss in Gao'an, Jiangxi province, China

BACKGROUND

The Rapid Assessment of Hearing Loss (RAHL) survey protocol aims to measure the prevalence and causes of hearing loss in a low cost and rapid manner, to inform planning of ear and hearing services. This paper reports on the first field-test of the RAHL in Gao'an County, Jiangxi Province, China. This study aimed to 1) To report on the feasibility of RAHL; 2) report on the estimated prevalence and causes of hearing loss in Gao'an.

METHODS

A cross-sectional population-based survey was conducted in September-October 2018. Forty-seven clusters in Gao'an County were selected using probability-proportionate-to-size sampling. Within clusters, compact segment sampling was conducted to select 30 people aged 50+. A questionnaire was completed covering sociodemographics, hearing health, and risk factors. Automated pure-tone audiometry was completed for all participants, using smartphone-based audiometry (hearTest), at 0.5, 1, 2, 4 kHz (kHz). All participants had their ears examined by an Ear Nose and Throat (ENT) doctor, using otoscopy, and probable causes of hearing loss assigned. Prevalence estimates were age and sex standardised to the Jiangxi population. Feasibility of a cluster size of 30 was examined by assessing the response rate, and the proportion of clusters completed in 1 day.

RESULTS

1344 of 1421 eligible participants completed the survey (94.6%). 100% of clusters were completed in 1 day. The survey was completed in 4.5 weeks. The prevalence of moderate or greater hearing loss (pure-tone average of 0.5, 1, 2, 4 kHz of > = 41dBHL in the better ear) was 16.3% (95% CI = 14.3, 18.5) and for any level of hearing loss (pure-tone average of > = 26dBHL in the better ear) the prevalence was 53.2% (95% CI = 49.2, 57.1). The majority of hearing loss was due to acquired sensorineural causes (91.7% left; 92.1% right). Overall 54.0% of the population aged 50+ (108,000 people) are in need of diagnostic audiology services, 3.4% were in need of wax removal (7000 people), and 4.8% were in need of surgical services (9500 people). Hearing aid coverage was 0.4%.

CONCLUSION

The RAHL survey protocol is feasible, demonstrated through the number of people examined per day, and the high response rate. The survey was completed in a much shorter period than previous all-age surveys in China. Some remaining challenges included assignment of causes of probable sensorineural loss. The data obtained from this survey can be used to scale-up hearing services in Gao'an.

Panel 6: Otitis media and associated hearing loss among disadvantaged populations and low to middle-income countries

OBJECTIVE:

Summarise the published evidence on otitis media and associated hearing loss in low to middle-income countries (LMIC) and disadvantaged populations.

DATA SOURCES:

PubMed and other databases.

REVIEW METHODS:

Firstly, sensitive search strategy using ‘otitis media’, combined with specific key words for each topic of the review, from January 2015 to June 2019. Then, restriction to LMIC and disadvantaged populations. Topics covered included prevention, epidemiology, risk factors, microbiology, prognosis, diagnosis, and treatment.

CONCLUSIONS:

There was a high degree of methodological heterogeneity and high risk of bias. The majority of studies were school-based. In Africa, Asia and Oceania (e.g., Australian Aboriginal populations) the prevalence of OM was respectively 8% (range 3–16%), 14% (range 7–22%) and 50% (4–95%). Prevalence of any hearing loss in these regions was 12% (range 8–17%), 12% (range 3–24%), and 26% (range 25–28%) respectively. Risk factors in LMIC and disadvantaged populations included age, gender, exposure to smoke and pollution. Microbiology was reported for otitis media with effusion at time of surgery or ear discharge (acute otitis media with perforation or chronic suppurative otitis media). Specimen handling and processing in hospital laboratories was associated with low detection of S. pneumoniae and H. influenzae. Case series described complicated cases of OM due to M. tuberculosis, multidrug resistance and HIV. QOL studies identified discrimination of persons with OM and hearing loss. Diagnostic methods varied greatly, from naked eye to tympanometry. Treatment interventions were reported from four RCTs. Non-RCTs included evaluations of guidelines, surgery outcomes, access to ENTs.

IMPLICATIONS FOR CLINICAL PRACTICE:

Chronic suppurative otitis media, otitis media with effusion and conductive hearing loss are common in LMIC and disadvantaged populations. Paucity of research, poor regional representation, non-standardised methods and low-quality reporting preclude accurate assessment of disease burden in LMIC and disadvantaged populations. Awareness and adherence to reporting Guidelines should be promoted.

Hearing Impairment Overview in Africa: the Case of Cameroon

The incidence of hearing impairment (HI) is higher in low- and middle-income countries when compared to high-income countries. There is therefore a necessity to estimate the burden of this condition in developing world. The aim of our study was to use a systematic approach to provide summarized data on the prevalence, etiologies, clinical patterns and genetics of HI in Cameroon. We searched PubMed, Scopus, African Journals Online, AFROLIB and African Index Medicus to identify relevant studies on HI in Cameroon, published from inception to 31 October, 2019, with no language restrictions. Reference lists of included studies were also scrutinized, and data were summarized narratively. This study is registered with PROSPERO, number CRD42019142788. We screened 333 records, of which 17 studies were finally included in the review. The prevalence of HI in Cameroon ranges from 0.9% to 3.6% in population-based studies and increases with age. Environmental factors contribute to 52.6% to 62.2% of HI cases, with meningitis, impacted wax and age-related disorder being the most common ones. Hereditary HI comprises 0.8% to 14.8% of all cases. In 32.6% to 37% of HI cases, the origin remains unknown. Non-syndromic hearing impairment (NSHI) is the most frequent clinical entity and accounts for 86.1% to 92.5% of cases of HI of genetic origin. Waardenburg and Usher syndromes account for 50% to 57.14% and 8.9% to 42.9% of genetic syndromic cases, respectively. No pathogenic mutation was described in GJB6 gene, and the prevalence of pathogenic mutations in GJB2 gene ranged from 0% to 0.5%. The prevalence of pathogenic mutations in other known NSHI genes was <10% in Cameroonian probands. Environmental factors are the leading etiology of HI in Cameroon, and mutations in most important HI genes are infrequent in Cameroon. Whole genome sequencing therefore appears as the most effective way to identify variants associated with HI in Cameroon and sub-Saharan Africa in general.

Fokouo JV, Oluwole OG, Nguefack S, Chimusa ER, Wonkam A. Hearing Impairment Overview in Africa: the Case of Cameroon

The incidence of hearing impairment (HI) is higher in low- and middle-income countries when compared to high-income countries. There is therefore a necessity to estimate the burden of this condition in developing world. The aim of our study was to use a systematic approach to provide summarized data on the prevalence, etiologies, clinical patterns and genetics of HI in Cameroon. We searched PubMed, Scopus, African Journals Online, AFROLIB and African Index Medicus to identify relevant studies on HI in Cameroon, published from inception to 31 October, 2019, with no language restrictions. Reference lists of included studies were also scrutinized, and data were summarized narratively. This study is registered with PROSPERO, number CRD42019142788. We screened 333 records, of which 17 studies were finally included in the review. The prevalence of HI in Cameroon ranges from 0.9% to 3.6% in population-based studies and increases with age. Environmental factors contribute to 52.6% to 62.2% of HI cases, with meningitis, impacted wax and age-related disorder being the most common ones. Hereditary HI comprises 0.8% to 14.8% of all cases. In 32.6% to 37% of HI cases, the origin remains unknown. Non-syndromic hearing impairment (NSHI) is the most frequent clinical entity and accounts for 86.1% to 92.5% of cases of HI of genetic origin. Waardenburg and Usher syndromes account for 50% to 57.14% and 8.9% to 42.9% of genetic syndromic cases, respectively. No pathogenic mutation was described in GJB6 gene, and the prevalence of pathogenic mutations in GJB2 gene ranged from 0% to 0.5%. The prevalence of pathogenic mutations in other known NSHI genes was <10% in Cameroonian probands. Environmental factors are the leading etiology of HI in Cameroon, and mutations in most important HI genes are infrequent in Cameroon. Whole genome sequencing therefore appears as the most effective way to identify variants associated with HI in Cameroon and sub-Saharan Africa in general.

Rationale and feasibility of a combined rapid assessment of avoidable blindness and hearing loss protocol

Purpose

This study has two main objectives: 1) to assess the value of combining the rapid assessment of avoidable blindness (RAAB) and the recently developed rapid assessment of hearing loss (RAHL) based on existing population-based data from Cameroon andIndia; 2) to test the feasibility of a combined RAAB-RAHL protocol.

Methods

A secondary data analysis of population-based disability surveys in India and Cameroon (in 2013–2014) was conducted, focussing on people aged 50+. Hearing impairment (HI) was defined as pure tone average of ≥41dB (better ear).Visual impairment (VI) was defined as presenting visual acuity of <6/18 (better eye). The relationship between HI and VI was examined. The feasibility of a combined RAAB-RAHL survey was assessed within a RAHL conducted among adults aged 50+ in Malawi in 2018. Outcomes included: time taken, costs, number of people examined in a day, and qualitative feedback from participants and field teams.

Results

The prevalence of combined VI and HI among people aged 50+ was 4.4% (95% confidence interval (CI) 3.0, 6.4) in India and 4.8% (95%CI 3.0, 8.0) in Cameroon. Among participants with VI, approximately a third in India (29.3%) and Cameroon (35.1%) also had HI. A quarter of participants in India (25.4%) and Cameroon (26.9%) who had HI also had VI. In Malawi, the total time taken to complete both RAAB and RAHL assessments was approximately 27 minutes per participant. It was feasible to complete 30 participants per day for a team of four people. The estimated cost of a combined RAAB-RAHL approach in comparison to two separate impairment surveys is up to 37% less depending on the method of combination.

Conclusion

The substantial overlap between VI and HI supports a combined rapid survey of the two impairments. The pilot study of a combined RAAB-RAHL survey demonstrates feasibility and lower cost compared to conducting two standalone impairment surveys. A combined RAAB-RAHL approach could maximize limited resources to increase prevalence data for both vision and hearing impairment.

Rationale for a Rapid Methodology to Assess the Prevalence of Hearing Loss in Population-Based Surveys

Data on the prevalence and causes of hearing loss is lacking from many low and middle-income countries, in part, because all-age population-based surveys of hearing loss can be expensive and time consuming. Restricting samples to older adults would reduce the sample size required, as hearing loss is more prevalent in this group. Population-based surveys of hearing loss require clinicians to be involved in the data collection team and reducing the duration of the survey may help to minimise the impact on service delivery. The objective of this paper was to identify the optimal age-group for conduct of population-based surveys of hearing loss, balancing sample size efficiencies, and expected response rates with ability to make inferences to the all-age population. Methods: Between 2013–2014, two all aged population-based surveys of hearing loss were conducted in one district each of India and Cameroon. Secondary data analysis was conducted to determine the proportion of hearing loss (moderate or greater) in people aged 30+, 40+ and 50+. Poisson regression models were developed to predict the expected prevalence of hearing loss in the whole population, based on the prevalence in people aged 30+, 40+, and 50+, which was compared to the observed prevalence. The distribution of causes in these age groups was also compared to the all-age population. Sample sizes and response rates were estimated to assess which age cut-off is most rapid. Results: Of 160 people in India and 131 in Cameroon with moderate or greater hearing loss, over 70% were older than 50 in both settings. For people aged 30+ (90.6% India; 76.3% Cameroon), 40+ (81% India; 75% Cameroon) and 50+ (73% India; 73% Cameroon) the proportions were higher. Prediction based on Poisson distributed observations the predicted prevalence based on those aged 30+, 40+, and 50+ fell within the confidence intervals of the observed prevalence. The distribution of probable causes of hearing loss in the older age groups was statistically similar to the total population. Sample size calculations and an analysis of response rates suggested that a focus on those aged 50+ would minimise costs the most by reducing the survey duration. Conclusion: Restricting the age group included in surveys of hearing loss, in particular to people aged 50+, would still allow inferences to be made to the total population, and would mean that the required sample size would be smaller, thus reducing the duration of the survey and costs.