Prevalence and Etiology of Hearing Loss in Rural Nicaraguan Children

Association Between In-Utero Exposure to Antibiotics and Offspring's Hearing Loss: A Systematic Review and Meta-Analysis

Objectives: Antibiotic exposure during pregnancy is common, accounting for over 80% of all medications prescribed. Antibiotics in pregnancy are linked to increased childhood disease risk, through direct toxicity or potentially microbiome dysbiosis. This systematic review investigated the relationship between in-utero exposure to antibiotics and childhood hearing loss. Methods: We searched Ovid Medline, Embase, and PubMed for studies examining antibiotic exposure during pregnancy and its associations with hearing loss in offspring. Studies with children whose mothers had data on antibiotic exposure during pregnancy were selected. The meta-analysis calculated (1) pooled prevalence of childhood hearing loss and (2) pooled odds ratios (ORs) for associations between in-utero exposure to antibiotics and childhood hearing loss. Results: Of 1244 studies identified, 18 met the inclusion criteria. Among 161,053 children exposed in-utero to antibiotics, 4368 developed hearing loss. The pooled prevalence of childhood hearing loss was 0.9% (95% CI 0.0-2.8%, I2 = 99.6%). In-utero exposure to antibiotics was associated with an increased risk of childhood hearing loss (pooled OR 1.2, 95% CI 1.1 to 1.3, I2 = 15.4%). Aminoglycoside exposure during pregnancy was associated with a higher risk of hearing loss (pooled OR 1.2, 95% CI 1.1 to 1.3, I2 = 38.4%), while exposure to other antibiotic classes showed no association. Conclusions: The prevalence of childhood hearing loss among those exposed to antibiotics during pregnancy is high. Although the overall risk appears modest, aminoglycosides are linked to a significantly higher risk, suggesting maternal aminoglycoside exposure may indicate a risk for child hearing loss. Further research is needed to clarify causal pathways and long-term effects of in-utero exposure to antibiotics.

Test-Retest repeatability of automated threshold audiometry in Nicaraguan schoolchildren

OBJECTIVE

Automated threshold audiometry (ATA) could increase access to paediatric hearing assessment in low- and middle-income countries, but few studies have evaluated test-retest repeatability of ATA in children. This study aims to analyse test-retest repeatability of ATA and to identify factors that affect the reliability of this method.

DESIGN

ATA was performed twice in a cohort of Nicaraguan schoolchildren. During testing, the proportion of responses occurring in the absence of a stimulus was measured by calculating a stimulus response false positive rate (SRFP). Absolute test-retest repeatability was determined between the two trials, as well as the impact of age, gender, ambient noise, head circumference, and SRFP on these results.

STUDY SAMPLE

807 children were randomly selected from 35 schools in northern Nicaragua.

RESULTS

Across all frequencies, the absolute value of the difference between measurements was 5.5 ± 7.8 dB. 89.6% of test-retest differences were within 10 dB. Intra-class correlation coefficients between the two measurements showed that lower SRFP was associated with improved repeatability. No effect of age, gender, or ambient noise was found.

CONCLUSIONS

ATA produced moderate test-retest repeatability in Nicaraguan schoolchildren. Participant testing behaviours, such as delayed or otherwise inappropriate response patterns, significantly impacts the repeatability of these measurements.

"Association of High Risk Factors and Hearing Impairment in Infants-A Hospital Based Study"

The aim of the study was to find the association of various risk factors with permanent hearing impairment in infants. A case-control study was designed on 420 infants with permanent hearing impairment and normal hearing. The case control ratio was 1:1. Alternate sampling method was used for selecting the control group. Review of medical records and parent interview was done to collect the information of risk factors. Family history(adj. OR 7.5; 95% CI 3, 14; P = 0.000), Consanguinity (adj. OR: 4; 95% CI 2,4; P = 0.000), intra uterine infection (adj. OR 18, 95% CI: 2.3-126.5, P = 0.000), post natal infection (adj. OR 3, 95% CI: 1.3-5, P = 0.004), low Apgar score (adj.OR: 4.6, 95% CI: 1.3-15), craniofacial anomaly (OR-4.6, 95% CI: 1.4-9.5, P = 0.005) and low birth weight (adj. OR: 2.3, 95% CI: 1.2-3.8) were significantly associated with hearing impairment. Among the risk factors, intra uterine infection was having highest significant association with permanent hearing impairment. This is followed by family history, low Apgar score, craniofacial anomaly, consanguinity, post natal infection and low birth weight.

School Hearing Screening With a Portable, Tablet-Based, Noise-Attenuating Audiometric Headset in Rural Nicaragua

OBJECTIVE

To investigate the utility and effectiveness of a noise-attenuating, tablet-based mobile health system combined with asynchronous telehealth evaluations for screening rural Nicaraguan schoolchildren for hearing loss.

STUDY DESIGN

Prospective population-based survey.

SETTING

Rural Nicaraguan communities.

PATIENTS

There were 3,398 school children 7 to 9 years of age.

INTERVENTIONS

Diagnostic automated and manual audiometry, detailed asynchronous telehealth evaluations.

MAIN OUTCOME MEASURES

Referral rates, ambient noise levels, and audiometric results as well as hearing loss prevalence, types, and risk factors.

RESULTS

Despite high ambient noise levels during screening (46.7 dBA), no effect of noise on referral rates on automated audiometry or confirmatory manual audiometry in those who failed automated testing was seen. The overall audiometric referral rate was 2.6%. Idiopathic sensorineural hearing loss (SNHL) and cerumen impaction were the most common types of hearing loss in this population with an estimated prevalence of hearing loss (all types) of 18.3 per 1,000 children. SNHL was associated with both drug exposure during pregnancy (p = 0.04) and pesticide exposure in the home (p = 0.03).

CONCLUSION

Hearing screening using a tablet-based, noise-attenuating wireless headset audiometer is feasible and effective in rural low-resource environments with moderately elevated ambient noise levels. The referral rate with noise-attenuating headsets was much lower than that previous reports on this population. In addition, manual audiometry resulted in much lower referral rates than automated audiometry. The confirmed hearing loss rate in this study is comparable to reports from other low-income countries that use some form of noise attenuation during screening. Pesticide exposure and drug exposure during pregnancy are potential causes of SNHL in this population.

Community health workers and mHealth systems for hearing screening in rural Nicaraguan schoolchildren

Background

We aimed to investigate the effectiveness of using minimally trained community health workers (CHW) to screen schoolchildren in rural Nicaragua for hearing loss using a tablet-based audiometric system integrated with asynchronous telehealth evaluations and mobile health (mHealth) appointment reminders.

Methods

A population-based survey was conducted using community health workers (CHWs) to perform tablet-based audiometry, asynchronous telehealth evaluations, and mHealth reminders to screen 3398 school children (7-9 years of age) in 92 rural Nicaraguan communities. The accuracy of screening, test duration, testing efficiency, telehealth data validity, and compliance with recommended clinic visits were analyzed.

Results

Minimally trained CHWs successfully screened children within remote rural schools with automated audiometry (test duration = 5.8 minutes) followed by manual audiometry if needed (test duration = 4.3 minutes) with an estimated manual audiometry validity of 98.5% based on a review of convergence patterns. For children who were referred based on audiometry, the otoscopy and tympanometry obtained during telehealth evaluations were high quality (as reviewed by 3 experts) in 44.6% and 80.1% of ears, respectively. A combination of automated short message service (SMS) text messages and voice reminders resulted in a follow-up compliance of 75.2%. No families responded to SMS messages alone.

Conclusions

Tablet-based hearing screening administered by minimally trained CHWs is feasible and effective in low- and middle-income countries. Manual audiometry was as efficient as automated audiometry in this setting. The physical exam tasks of otoscopy and tympanometry require additional training. Mobile phone messages improve compliance for confirmatory audiometry, but the utility of SMS messaging alone is unclear in this population.

Genetic etiology of non-syndromic hearing loss in Latin America

Latin America comprises all countries from South and Central America, in addition to Mexico. It is characterized by a complex mosaic of regions with heterogeneous genetic profiles regarding the geographical origin of the ancestors and proportions of admixture between the Native American, European and African components. In the first years following the findings of the role of the GJB2/GJB6 genes in the etiology of hearing loss, most scientific investigations about the genetics of hearing loss in Latin America focused on assessing the frequencies of pathogenic variants in these genes. More recently, modern techniques allowed researchers in Latin America to make exciting contributions to the finding of new candidate genes, novel mechanisms of inheritance in previously known genes, and characterize a wide diversity of variants, many of them unique to Latin America. This review aimed to provide a general landscape of the genetic studies about non-syndromic hearing loss in Latin America and their main scientific contributions. It allows the conclusion that, although there are similar contributions of some genes, such as GJB2/GJB6, when compared to European and North American countries, Latin American populations revealed some peculiarities that indicate the need for tailored strategies of screening and diagnosis to specific geographic regions.

Development of a public audiology service in Southern Malawi: profile of patients across two years

OBJECTIVE

To describe the profile of patients attending the Queen Elizabeth Central Hospital (QECH) audiology clinic in Malawi, over a two-year period (2016-2017).

DESIGN

A retrospective patient record review.

STUDY SAMPLE

There were 2299 patients assessed at the QECH audiology department between January 2016 and December 2017. Adult patients' ages ranged from 18 to 94 years (M = 45.8, SD = 19.22). The mean age of children included in this study was 7.7 years (SD= 5.21). Overall, 45.4% of patients were female.

RESULTS

Of the 61.6% of adults and 41.7% of children found to have some degree of hearing loss, 28.3% and 15.4% were fitted with hearing aids, respectively. The number of patients seen in 2017 (n = 1385) was 34% higher than that of 2016 (n = 914).

CONCLUSION

This study found that demand for hearing services is increasing in this public sector Malawian audiology department but uptake of hearing aids for those in need is low. Future evaluation of service provision and treatment outcomes is needed. Results from this study can be used to inform the development of future audiology clinics in low resource settings.

Etiology of newborn hearing impairment in Guangdong province: 10-year experience with screening, diagnosis, and follow-up

BACKGROUND

Hearing impairment is one of the most common birth defects in children. Universal newborn hearing screenings have been performed for 19 years in Guangdong province, China. A screening/diagnosis/intervention system has gradually been put in place. Over the past 10 years, a relatively complete data management system had been established. In the present study, an etiological analysis of newborn cases that failed the initial and follow-up screenings was performed.

METHODS

The nature and degree of hearing impairment in newborns were confirmed by a set of procedures performed at the time of initial hearing screening, rescreening and final hearing diagnosis. Then, multiple examinations were performed to explore the associated etiology.

RESULTS

Over a period of 10 years, 720 children were diagnosed with newborn hearing loss. Among these children, 445 (61.81%) children had a clearly identified cause, which included genetic factor(s) (30.56%), secretory otitis media (13.30%), maternal rubella virus infection during pregnancy (5.83%), inner ear malformations (4.86%), maternal human cytomegalovirus infection during pregnancy (2.92%), malformation of the middle ear ossicular chain (2.50%) and auditory neuropathy (1.81%). In addition, 275 cases of sensorineural hearing loss of unknown etiology accounted for 38.19% of the children surveyed.

CONCLUSIONS

Long-term follow-up is needed to detect delayed hearing impairment and auditory development in children. The need for long-term follow-up should be taken into account when designing an intervention strategy. Furthermore, the use of the deafness gene chip should further elucidate the etiology of neonatal hearing impairment.

Reliability of Tablet-based Hearing Testing in Nicaraguan Schoolchildren: A Detailed Analysis

OBJECTIVE

Determine whether an electronic tablet-based Wireless Automated Hearing-Test System can perform high-quality audiometry to assess schoolchildren for hearing loss in the field in Nicaragua.

STUDY DESIGN

Cross-sectional.

SETTING

A school and hospital-based audiology clinic in Jinotega, Nicaragua.

SUBJECTS AND METHODS

Second and third graders (n = 120) were randomly selected for hearing testing in a school. Air conduction hearing thresholds were obtained bilaterally using a Wireless Automated Hearing-Test System at 1000, 2000, and 4000 Hz. Referral criteria were set at more than 25 dBHL at one or more frequencies. A cohort of children was retested with conventional audiometry in a hospital-based sound booth. Factors influencing false-positive examinations, including ambient noise and behavior, were examined.

RESULTS

All children with hearing loss were detected using an automated, manual, or two-step (those referred from automated testing were tested manually) protocol in the school (sensitivity = 100%). Specificity was 76% for automated testing, 97% for manual testing, and 99% for the two-step protocol. The variability between thresholds obtained with automated testing was greater than manual testing when compared with conventional audiometry. The percentage of participant responses when no stimulus tone was presented during automated testing was higher in children with false-positive examinations.

CONCLUSION

A Wireless Automated Hearing-Test System identified all children with hearing loss in a challenging field setting. A two-step protocol (those referred from automated testing are tested manually) reduced false-positive examinations and unnecessary referrals. Children who respond frequently when no tone is presented are more likely to have false-positive automated examinations and should be tested manually.

Systematic Review of Pathogenic GJB2 Variants in the Latino Population

OBJECTIVES

Define the extent to which GJB2-related hearing loss is responsible for non-syndromic hearing loss (NSHL) in the Latino population.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were followed. PubMed and MEDLINE were accessed from 1966 to 2019 using permutations of the MeSH terms: "Hearing Loss," "Hearing Impairment," "Deafness," "Latin American," "Latino," "GJB2," and "Genetic." Additionally, countries designated as Latino by the US Office of Management and Bureau were cross-referenced as key terms against the aforementioned search criteria. Exclusion criteria included non-English publications, a non-Latino study population, and literature not investigating GJB2. An allele frequency analysis of pathogenic GJB2 variants in the Latino population was performed and stratified by country of origin and reported ethnicity.

RESULTS

One hundred twenty two unique studies were identified of which 64 met our inclusion criteria. Forty three studies were included in the GJB2 systematic review. A total of 38 pathogenic GJB2 variants were identified across 20 countries in the Latino population. The prevalence of pathogenic GJB2 variants varied by country; however, were generally uncommon with the exception of c.35delG (p.Gly12Valfs*) which displayed an allele frequency of 3.1% in the combined Latino population; ranging from 21% in Colombia to 0% in Guatemala.

CONCLUSION

Variation in the prevalence of pathogenic GJB2 variants by country likely reflect the heterogeneous nature of ethnic ancestral contributions to the Latino population. Additional research utilizing next generation sequencing might aid in the development of assays for high throughput diagnosis of inherited hearing loss in the multitude of ethnic sub-groups that comprise this and other traditionally marginalized populations.

Hearing consequences in Gjb2 knock-in mice: implications for human p.V37I mutation

Human p.V37I mutation of GJB2 gene was strongly correlated with late-onset progressive hearing loss, especially among East Asia populations. We generated a knock-in mouse model based on human p.V37I variant (c.109G>A) that recapitulated the human phenotype. Cochlear pathology revealed no significant hair cell loss, stria vascularis atrophy or spiral ganglion neuron loss, but a significant change in the length of gap junction plaques, which may have contributed to the observed mild endocochlear potential (EP) drop in homozygous mice lasting lifetime. The cochlear amplification in homozygous mice was compromised, but outer hair cells' function remained unchanged, indicating that the reduced amplification was EP- rather than prestin-generated. In addition to ABR threshold elevation, ABR wave I latencies were also prolonged in aged homozygous animals. We found in homozygous IHCs a significant increase in I_Ca but no change in Ca²⁺ efficiency in triggering exocytosis. Environmental insults such as noise exposure, middle ear injection of KCl solution and systemic application of furosemide all exacerbated the pathological phenotype in homozygous mice. We conclude that this Gjb2 mutation-induced hearing loss results from 1) reduced cochlear amplifier caused by lowered EP, 2) IHCs excitotoxicity associated with potassium accumulation around hair cells, and 3) progression induced by environmental insults.

An Evidence-Based Practical Approach to Pediatric Otolaryngology in the Developing World

Despite humanitarian otolaryngology groups traveling in record numbers to resource-limited areas treating pediatric otolaryngology disease processes and training local providers, there remains a large burden of unmet needs. There is a meager amount of published information that comes from the developing world from an otolaryngology standpoint. As would be expected, the little information that does comes involves some of the most common pediatric otolaryngology diseases and surgical burdens including childhood hearing loss, otitis media, adenotonsillectomies, airway obstructions requiring tracheostomies, foreign body aspirations, and craniomaxillofacial surgeries, including cleft lip and palate.

An innovative approach to improve ear, nose and throat surgical access for remote living Cape York Indigenous children

INTRODUCTION

On a background of high rates of severe otitis media (OM) with associated hearing loss, children from the Torres Strait and Cape York region requiring ear, nose and throat (ENT) surgery, faced waiting times exceeding three years. After numerous clinical safety incidents were raised, indicating a failure of the current system to deliver appropriate care, the governing Hospital and Health service opted to deliver surgical care through an alternate process. ENT surgeries were performed on 16 consented children from two remote locations via the private health care system, funded by a health provider partnership.

METHODS

We examined the collaboration processes alongside clinical findings from this ENT surgery. Collated patient data, included patient demographics, clinical and audiometry presentation features were reviewed and compared pre and post-operatively. Cost savings associated with the use of TeleHealth post-operatively were briefly examined.

RESULTS

Surgeries were successfully completed in all 16 children. The reported mean waitlist time for ENT surgery was 1.2 years. Pre-surgery pure-tone average hearing thresholds were reported at left: 30.9 dB, right: 38.2 dB. The majority of presentations were for bilateral OM with Effusion (69%). Post-surgical follow up indicated successful clinical outcomes in 80% of patients and successful hearing outcomes in 88% of patients. Mean difference pure-tone average hearing thresholds, left: 8.4 dB and right: 11.2 dB. Furthermore, the majority of patients reported improved hearing and breathing. The use of TeleHealth for post-operative review enabled a minimum cost saving of AUD$21,664 for these 16 children. Overall, a high level of staffing resources was required to successfully coordinate this intense surgical activity.

CONCLUSION

This innovative approach to a health system crisis enabled successful ENT surgical and hearing outcomes in 16 children, whose waitlisted time grossly exceeded state health recommendations. Using private health facilities funded by a health partnership, while unlikely to be a suitable model of care for routine service delivery; may be applied as an adjunct service model when blockages and delays lead to sub-standard service provision. This approach may be applicable to other health care facilities when facing extended elective surgery wait times in ENT or other specialty areas.

Otoacoustic Emissions in Rural Nicaragua: Cost Analysis and Implications for Newborn Hearing Screening

Objective (1) Determine the incidence and risk factors for congenital hearing loss. (2) Perform cost analysis of screening programs. Study Design Proportionally distributed cross-sectional survey. Setting Jinotega, Nicaragua. Subjects and Methods Otoacoustic emissions (OAEs) were used to screen 640 infants <6 months of age from neonatal intensive care unit, institutional, and home birth settings. Data on 15 risk factors were analyzed. Cost of 4 implementation strategies was studied: universal screening, screening at the regional health center (RHC), targeted screening, and screening at the RHC plus targeted screening. Cost-effectiveness analysis over 10 years was based on disability-adjusted life year estimates, with the World Health Organization standard of cost-effectiveness ratio (CER) / gross domestic product (GDP) <3, with GDP set at $4884.15. Results Thirty-eight infants failed the initial OAE (5.94%). In terms of births, 325 (50.8%) were in the RHC, 69 (10.8%) in the neonatal intensive care unit, and 29 (4.5%) at home. Family history and birth defect were significant in univariate analysis; birth defect was significant in multivariate analysis. Cost-effectiveness analysis demonstrated that OAE screening is cost-effective without treatment (CER/GDP = 0.06-2.00) and with treatment (CER/GDP = 0.58-2.52). Conclusions Our rate of OAE failures was comparable to those of developed countries and lower than hearing loss rates noted among Nicaraguan schoolchildren, suggesting acquired or progressive etiology in the latter. Birth defects and familial hearing loss correlated with OAE failure. OAE screening of infants is feasible and cost-effective in rural Nicaragua, although highly influenced by estimated hearing loss severity in identified infants and the high travel costs incurred in a targeted screening strategy.

Measuring Success: Cost-Effectiveness and Expanding Access to Cochlear Implantation

Only a small fraction of patients with profound sensorineural hearing loss have access to cochlear implantation with the majority of these affected people living in developing countries. Cost effectiveness analysis (CEA) is an important tool to demonstrate the value of this technology to healthcare policy makers. This approach requires that hearing healthcare professionals incorporate methods of assessing long-term benefits of cochlear implantation that include psychosocial, quality of life, and disability outcomes. This review explores different aspects of CEA methodology relevant to cochlear implants and discusses ways that we can improve global access by addressing factors that influence cost-effectiveness.

The prevalence of hearing impairment within the Cape Town Metropolitan area

BACKGROUND

There is a lack of data on the prevalence of hearing impairment in South Africa. Current data is unreliable as it is based on national census information which tends to underestimate the prevalence of hearing impairment.

AIM

The aim of this study was to estimate the prevalence of hearing impairment in the Cape Town Metropolitan area and to determine factors associated with hearing impairment.

METHOD

A cross-sectional household survey involving 2494 partcipants from 718 households was conducted between the months of February and October 2013. Random cluster sampling was used to select four health sub-districts from eight health sub-districts in the Cape Town Metropolitan area using a method of probability proportional to size (PPS). The survey was conducted according to the World Health Organization (WHO) Ear and Hearing Disorders Survey Protocol and the classifcation of hearing impairment matched the WHO's criteria for the grading of hearing impairment.

RESULTS

The overall prevalence of hearing impairment in the population of this study was 12.35% (95%CI: 11.06% - 13.64%) and prevalence of disabling hearing impairment was 4.57% (95% CI: 3.75% - 5.39%) amongst individuals ≥ 4 years old. The following factors were found to be associated with hearing impairment; male gender, age, hypertension, a history of head and neck trauma and a family history of hearing impairment.

CONCLUSION

Based on the data from communities surveyed during this study, hearing impairment is more prevalent than previously estimated based on national population census information. Interventions for the prevention of hearing impairment in these communities should focus on individuals with associated risk factors.

Cost Effectiveness of Childhood Cochlear Implantation and Deaf Education in Nicaragua: A Disability Adjusted Life Year Model

INTRODUCTION

Cochlear implantation (CI) is a common intervention for severe-to-profound hearing loss in high-income countries, but is not commonly available to children in low resource environments. Owing in part to the device costs, CI has been assumed to be less economical than deaf education for low resource countries. The purpose of this study is to compare the cost effectiveness of the two interventions for children with severe-to-profound sensorineural hearing loss (SNHL) in a model using disability adjusted life years (DALYs).

METHODS

Cost estimates were derived from published data, expert opinion, and known costs of services in Nicaragua. Individual costs and lifetime DALY estimates with a 3% discounting rate were applied to both two interventions. Sensitivity analysis was implemented to evaluate the effect on the discounted cost of five key components: implant cost, audiology salary, speech therapy salary, number of children implanted per year, and device failure probability.

RESULTS

The costs per DALY averted are $5,898 and $5,529 for CI and deaf education, respectively. Using standards set by the WHO, both interventions are cost effective. Sensitivity analysis shows that when all costs set to maximum estimates, CI is still cost effective.

CONCLUSION

Using a conservative DALY analysis, both CI and deaf education are cost-effective treatment alternatives for severe-to-profound SNHL. CI intervention costs are not only influenced by the initial surgery and device costs but also by rehabilitation costs and the lifetime maintenance, device replacement, and battery costs. The major CI cost differences in this low resource setting were increased initial training and infrastructure costs, but lower medical personnel and surgery costs.

Gentamicin extended interval regimen and ototoxicity in neonates

OBJECTIVES

To assess the extended interval regimen gentamicin associated ototoxicity in neonatal intensive care unit using hearing tests.

METHODS

Two hundred and twenty neonates admitted to neonatal intensive care were assessed; 110 neonates who had received gentamicin and 110 neonates who had not received gentamicin served as control group. Gentamicin group were further subdivided according to the duration of treatment into 50 neonates who had received gentamicin for 5 days or less and 60 neonates who had received gentamicin for more than 5 days. TEOAEs were used for hearing screening. Auditory brain response was performed 3 months later for failed cases to confirm the hearing impairment.

RESULTS

Three neonates failed TEOAEs screening in each group but hearing impairment was confirmed in one neonate only (0.9%) in each group (gentamicin and control groups). Neonates who received gentamicin for more than 5 days showed comparable results as regard TEOAEs or ABR results with those who received gentamicin for 5 days or less, and control group.

CONCLUSIONS

Extended interval dosing of gentamicin therapy in neonates does not increase the incidence of hearing loss. This suggests that hearing loss in neonatal intensive care unit may be attributed to factors other than gentamicin treatment.

Profile of patients assessed for cochlear implants

INTRODUCTION

Knowledge of the characteristics related to profound hearing loss is a matter of great importance, as it allows for the etiological and prognostic identification and strategic planning for public health interventions.

OBJECTIVE

To assess the different etiologies of hearing loss, age at diagnosis of the hearing loss, its relation to language acquisition, and the age at the first consultation in this service for cochlear implant assessment.

METHODS

This was a historical cohort, cross-sectional study, using retrospective analysis of the records of 115 patients with confirmed sensorineural hearing loss, who were followed in a university hospital, based on gender, age of hearing loss, age at the first consultation, language, and hearing loss etiology.

RESULTS AND CONCLUSION

The majority of patients assessed for cochlear implants attend the first consultation when they are older than one year (an alarming mean of 3.8 years in the prelingual group) in spite of the early diagnosis of hearing loss. This reflects an already deficient health care system, in terms of referral. The idiopathic cause remains the most frequently identified. Among the known causes, the most prevalent are perinatal causes and meningitis.

The global burden of disabling hearing impairment: a call to action

At any age, disabling hearing impairment has a profound impact on interpersonal communication, psychosocial well-being, quality of life and economic independence. According to the World Health Organization's estimates, the number of people with such impairment increased from 42 million in 1985 to about 360 million in 2011. This last figure includes 7.5 million children less than 5 years of age. In 1995, a "roadmap" for curtailing the burden posed by disabling hearing impairment was outlined in a resolution of the World Health Assembly. While the underlying principle of this roadmap remains valid and relevant, some updating is required to reflect the prevailing epidemiologic transition. We examine the traditional concept and grades of disabling hearing impairment - within the context of the International Classification of Functioning, Disability and Health - as well as the modifications to grading that have recently been proposed by a panel of international experts. The opportunity offered by the emerging global and high-level interest in promoting disability-inclusive post-2015 development goals and disability-free child survival is also discussed. Since the costs of rehabilitative services are so high as to be prohibitive in low- and middle-income countries, the critical role of primary prevention is emphasized. If the goals outlined in the World Health Assembly's 1995 resolution on the prevention of hearing impairment are to be reached by Member States, several effective country-level initiatives - including the development of public-private partnerships, strong leadership and measurable time-bound targets - will have to be implemented without further delay.

Investigação etiológica da deficiência auditiva em neonatos identificados em um programa de triagem auditiva neonatal universal

Objetivo descrever os resultados da investigação etiológica da deficiência auditiva realizada em neonatos rastreados em um programa de triagem auditiva neonatal universal. Métodos estudo descritivo, transversal e prospectivo. Foram incluídos no estudo todos os neonatos diagnosticados com deficiência auditiva identificados em um programa de triagem auditiva neonatal universal no período de agosto de 2003 a dezembro de 2006. A provável etiologia da deficiência auditiva foi determinada após anamnese detalhada realizada pelo médico otorrinolaringologista; pesquisa das sorologias para toxoplasmose, rubéola, citomegalovírus, herpes, sífilis e HIV; tomografia dos ossos temporais e exames genéticos. Resultados foram diagnosticados 17 sujeitos com deficiência auditiva no período estudado. 64.7% dos casos estudados apresentaram como provável etiologia causas pré-natais, 29.4% causas peri-natais e um sujeito (5,9%) apresentou etiologia desconhecida. Das causas pré-natais, 36.4% tiveram origem genética confirmada e 36.4% etiologia presumida de hereditariedade. Foi confirmada a presença de infecções congênitas em 18.2% dos casos e um sujeito (9%) apresentou anomalia craniofacial como provável etiologia. O grau de perda auditiva mais frequente observado nos sujeitos estudados foi o profundo (47,1%). Conclusão a maior ocorrência de etiologias observada neste estudo foram as de origem pré-natal, seguida das de origem peri-natal.

Hearing screening for school children: utility of noise-cancelling headphones

BACKGROUND

Excessive ambient noise in school settings is a major concern for school hearing screening as it typically masks pure tone test stimuli (particularly 500 Hz and below). This results in false positive findings and subsequent unnecessary follow-up. With advances in technology, noise-cancelling headphones have been developed that reduce low frequency noise by superimposing an anti-phase signal onto the primary noise. This research study examined the utility of noise-cancelling headphone technology in a school hearing screening environment.

METHODS

The present study compared the audiometric screening results obtained from two air-conduction transducers-Sennheiser PXC450 noise-cancelling circumaural headphones (NC headphones) and conventional TDH-39 supra-aural earphones. Pure-tone hearing screening results (500 Hz to 4000 Hz, at 30 dB HL and 25 dB HL) were obtained from 232 school children, aged 6 to 8 years, in four Hong Kong primary schools.

RESULTS

Screening outcomes revealed significant differences in referral rates between TDH-39 earphones and NC headphones for both 30 dB HL and 25 dB HL criteria, regardless of the inclusion or exclusion of 500 Hz results. The kappa observed agreement (OA) showed that at both screening intensities, the transducers' referral agreement value for the 500 Hz inclusion group was smaller than for the 500 Hz exclusion group. Individual frequency analysis showed that the two transducers screened similarly at 1000 Hz and 2000 Hz at 25 dB HL, as well as at both 30 dB HL and 25 dB HL screening levels for 4000 Hz. Statistically significant differences were found for 500 Hz at 30 dB HL and at 25 dB HL, and for 1000 Hz and 2000 Hz at 30 dB HL. OA for individual frequencies showed weaker intra-frequency agreement between the two transducers at 500 Hz at both intensity criterion levels than at higher frequencies.

CONCLUSIONS

NC headphones screening results differed from those obtained from TDH-39 earphones, with lower referral rates at 500 Hz, particularly at the 25 dB HL criterion level. Therefore, NC headphones may be able to operate at lower screening intensities and subsequently increase pure-tone screening test sensitivity, without compromising specificity. NC headphones show some promise as possible replacements for conventional earphones in school hearing screening programs.

Hearing loss and heavy metal toxicity in a Nicaraguan mining community: audiological results and case reports

We measured fingernail metal levels, Békésy-type pure-tone thresholds and distortion product otoacoustic emission (DPOAE) levels in 59 subjects residing in the gold mining community of Bonanza, Nicaragua. Auditory testing revealed widespread hearing loss in the cohort. Nail metal concentrations (mercury, lead, aluminum, manganese and arsenic) far exceeded reference levels. No relationship was found between metal levels and auditory test results for the group as a whole. Statistically significant relationships were found between DPOAE response amplitudes and metal concentrations in a subgroup with less than 40 h per week of significant noise exposure; however, conclusions regarding these relationships should be tempered by the large number of analyses performed. Several young individuals with high metal levels reported neurological symptoms and had poor hearing. The data suggest that metal levels in artisanal mining communities present a significant public health problem and may affect hearing.

A novel technique of otic barotrauma management using modified intravenous cannulae

This article provides the first detailed description and systematic evaluation of the management of otic barotrauma using modified intravenous cannulae. A 24-gauge IC cannula was modified as a tool for tympanostomy tube placement and middle ear ventilation. The medical records of 271 ears of 156 adult patients (median age 49 years) who underwent this procedure were reviewed retrospectively. Hundred and ninty-one tubes were placed for otalgia because of hyperbaric oxygen therapy, 58 tubes were inserted for air travel prophylaxis and 22 tubes were placed for management of otic barotrauma post-flight. All the patients who had this procedure for prophylaxis experienced regular otic barotrauma symptoms during air travel prior to tube placement. All patients were reviewed 6 weeks (range 2-9 weeks) post-procedure. This technique of otic barotrauma management worked effectively in 99 % of treated patients. On follow-up, 88 % of tubes were found to be extruded and non-extruded tubes were removed in clinic without any anaesthesia. 99.6 % of tympanic membrane had healed completely and spontaneously without sequelae. Given the safety, effectiveness, low risk of complications associated with this novel tympanostomy technique, it provided a simple yet effective therapeutic option for the management of otic barotrauma. Finally, this technique can be easily applied in all health settings as it only requires medical supplies readily available in hospitals, therefore there is no additional cost.

Cochlear Implantation in Developing Countries as Humanitarian Service

Objective. To make recommendations concerning cochlear implantation during humanitarian medical trips by exploring the attitudes of US cochlear implant surgeons.

Study Design. Cross-sectional survey.

Setting. Academic.

Subjects and Methods. Questionnaires were sent to 405 members of the William House Cochlear Implant Study Group. The 198 respondents (49%), all active cochlear implant surgeons, were divided into 3 groups depending on their level of experience working in a developing country.

Results. Eighty-nine percent of respondents supported cochlear implants in these environments, although 42% of these cochlear implant surgeons stated that they would modify their criteria for implantation considering the challenges in developing countries. There was strong support for cochlear implants in postlingual deafened patients and prelingual deafened patients under the age of 3 years, although nearly half of respondents (48%) would not implant prelingual deafened patients after they reached the age of 3 years. Three-quarters of respondents (74%) believed that developing countries should have the same access to current multichannel devices used in developed countries, as opposed to simpler, possibly lower cost devices. A local audiologist was deemed the most important personnel requirement (83%), and limited audiology and rehabilitative resources were the greatest postoperative concern rather than lack of postoperative care or infection.

Conclusion. This survey strongly supports the practice of performing cochlear implants during humanitarian trips to developing countries and makes best-practice recommendations to make outcomes successful.

Sensorineural hearing loss in high school teenagers in Mexico City and its relationship with recreational noise

The aim of this study was to measure the frequency of hearing loss in a sample of typical public high-school students exposed to recreational noise, and determine associated risk factors. The sample was made up of 214 teenagers from a high-school in Mexico City; subjects were selected randomly per strata. We applied a questionnaire to identify risk factors for hearing loss and performed a battery of audiologic tests consisting of otoscopy, tympanometry, and pure-tone audiometry. The mean age of the sample was 16 +/- 1.07 years; 73% were male and 27%, female. Hearing loss was found in 21% of students. The main hearing loss-related risk factor was exposure to recreational noise: frequent attendance at discotheques and pop-music concerts; use of personal stereos; and noise exposure in school workshops. The high frequency of hearing loss in high school students from one Mexico City school (nearly one fifth of the sample) was found to be related to noise exposure mainly during recreational activities.

Prevalence and Risk Factors of Hearing Impairment Among Primary-School Children in Shebin El-Kom District, Egypt

Purpose

This study examined the feasibility of screening hearing loss in rural and urban schools in Egypt, and investigated the prevalence and causes of hearing impairment (HI) in Egyptian primary-school students.

Method

A total of 555 children (6–12 years of age) from a rural and an urban school in the Shebin El-Kom District of Egypt were screened for HI at their schools. A 2-stage screening procedure was used, and positive cases were referred for a diagnostic hearing assessment at a regional medical facility. Risk factors were investigated through a parent questionnaire and an environmental study consisting of noise, ventilation, and crowding measurements at the schools.

Results

The screening failure rate was 25.6%, and the prevalence of confirmed HI was 20.9%. The rate of HI did not differ across the schools. Conductive hearing loss of minimal to mild severity was the most common type of HI. The most important predictors for HI were parent suspicion, otitis media, household smoking, low socioeconomic status, and postnatal jaundice.

Conclusions

The prevalence of HI did not differ across settings and was more common than reported in children from developed countries. The screening results also suggest that professionals with limited audiology background can be trained to implement hearing screening programs in Egyptian schools.

Hearing impairment and poverty: the epidemiology of ear disease in Peruvian schoolchildren

OBJECTIVES

1) To measure prevalence of hearing impairment (HI) in schoolchildren living in poverty in Peru. 2) To identify risk factors for HI and assess its impact on academic performance.

STUDY DESIGN

Cross-sectional.

SETTING

Elementary schools in an asentimiento humano (shantytown) near Lima, Peru, October 2008 to March 2009.

SUBJECTS

Schoolchildren (n = 335), ages six to 19 years.

METHODS

Audiological health was assessed with pure-tone audiometry, tympanometry, and otoscopy. The primary outcome was HI, defined as average threshold >25 dB HL for 0.5, 1, 2, and 4 kHz, in one or both ears (per World Health Organization/International Organization for Standardization). A questionnaire on health history was administered to parents. Statistical analysis included univariate analysis for chi(2) values and odds ratios (ORs), and multivariate logistic regression.

RESULTS

HI prevalence: 6.9 percent (95% confidence interval [CI] 4.2%-9.6%). Risk factors for HI (OR, 95% CI, P value): neonatal jaundice (5.59, 1.63-19.2, 0.015), seizure (7.31, 2.50-21.4, 0.0013), hospitalization (4.01, 1.66-9.68, 0.003), recurrent otitis media (5.06, 1.98-12.9, 0.002), past otorrhea (4.70, 1.84-12.0, 0.003), family history of HI at <35 years (2.91, 1.19-7.14, 0.026), tympanic membrane abnormality (13.8, 4.48-42.7, <0.001), cerumen impaction (15.8, 4.71-53.1, <0.001), and eustachian tube dysfunction (4.87, 1.74-13.7, <0.001). HI was an independent predictor of academic failure (3.36, 1.15-9.82, 0.03).

CONCLUSIONS

Impoverished Peruvian schoolchildren were four to seven times more likely to experience HI than children living in higher-income countries. Untreated middle ear disease in the context of limited access to pediatric care was a major risk factor for HI. Furthermore, HI was associated with worse scholastic achievement. These results support prioritization of pediatric ear health as an essential component of the global health agenda, especially in resource-poor countries.

Costs of screening children for hearing disorders and delivery of hearing aids in China

Background

The burden of disease of hearing disorders among children is high, but a large part goes undetected. School-based screening programs in combination with the delivery of hearing aids can alleviate this situation, but the costs of such programs are unknown.

Aim

To evaluate the costs of a school-based screening program for hearing disorders, among approximately 216,000 school children, and the delivery of hearing aids to 206 children at three different care levels in China.

Methods

In a prospective study design, screening and hearing aid delivery costs were estimated on the basis of program records and an empirical assessment of health personnel time input. Household costs for seeking and undergoing hearing health care were collected with a questionnaire, administered to the parents of the child. Data were collected at three study sites representing primary, secondary and tertiary care levels.

Results

Total screening and hearing aid delivery costs ranged between RMB70,000 (US$9,000) and RMB133,000 (US$17,000) in the three study sites. Health care cost per child fitted ranged from RMB5,900 (US$760) at the primary care level, RMB7,200 (US$940) at the secondary care level, to RMB8,600 (US$1,120) at the tertiary care level. Household costs were only a small fraction of the overall costs. Cost per child fitted ranged between RMB1,608 and RMB2,812 (US$209–US$365), depending on perspective of analysis and study site. The program was always least costly in the primary care setting.

Conclusion

Hearing screening and the delivery of hearing aids in China is least costly in a primary care setting. Important questions remain concerning its implementation.

Aminoglycoside ototoxicity in Nicaraguan children: patient risk factors and mitochondrial DNA results

OBJECTIVE

Aminoglycoside ototoxicity remains a major problem in developing countries and accounts for 3 percent to 30 percent of hearing loss. This high prevalence rate may be related to genetic susceptibility from mitochondrial mutations in the 12S rRNA gene, comorbidity factors, or unregulated use of the medication. This study investigates the risk factors and prevalence of mtDNA mutations in serum from rural Nicaragua children with aminoglycoside-related hearing loss.

STUDY DESIGN

Cross sectional study.

SUBJECTS

Deaf children from rural Nicaragua.

METHODS

Mitochondrial DNA isolated from serum collected from 31 deaf children with childhood or in utero exposure to gentamicin was amplified, sequenced, and analyzed for mutations in the 12S rRNA gene.

RESULTS

No known pathologic mutations of the 12S rRNA gene were identified in this subpopulation of deaf children. In addition, patients with gentamicin exposure were often likely to have other comorbidity factors.

CONCLUSION

These results suggest that genetic susceptibility is not a major factor in the high rate of gentamicin ototoxicity in this population sample. The high prevalence of gentamicin ototoxicty in this population is presumed to be due to unrestricted access to the drug.