Neonatal hearing screening in a rural/sub-urban community in Nigeria, sub-Saharan Africa-a preliminary report

Neonatal hearing screening using a smartphone-based otoacoustic emission device: A comparative study

OBJECTIVE

Increasing options are becoming available for clinicians and healthcare professionals who use smartphone-based applications (apps) to identify hearing loss. The use of smartphone-based apps for newborn hearing screening (NHS) has been proposed as an alternative screening method in NHS programs. This study aims to compare the screening outcomes of a smartphone-based otoacoustic emission (OAE) screening device to a commercially available OAE screening device.

METHODS

NHS was conducted in the post-natal maternity ward and neonatal intensive care unit (NICU) of two tertiary public healthcare hospitals over a period of 8 months. Within participant DPOAE and TEOAE screening outcomes of a smartphone-based OAE device (hearOAE) were compared to that of the Otodynamics ILO V6.

RESULTS

A total of 176 infants (n = 352 ears; 48.9 % female) underwent NHS (DPOAE n = 176; TEOAE n = 176). The mean age at was 4.5 days (SD 11.3). Signal-to-noise ratio (SNR) were higher with the hearOAE with TEOAE NHS, and equivalent or higher SNR at four out of six frequencies with DPOAEs. Mean and total noise levels were significantly lower for the hearOAE compared to the Otodynamics with DPOAEs noise levels of five out of six frequencies being equivalent to, or lower than the Otodynamics (p < 0.001). Lower noise levels are likely to be advantageous in less-than-ideal test conditions. Inter-device DPOAE comparison indicated no statistically significant difference in the refer rate between the devices (p = 0.238). DPOAE pass rates between devices differed in 6 ears (p > 0.05), and in 20 ears for TEOAEs, with the hearOAE demonstrating a higher TEOAE pass rate (p = 0.009). The hearOAE did, however, demonstrate lower noise levels at three out five frequencies, which may have impacted the pass rate. No statistically significant correlation was found between the independent variables and the screening outcome (pass/refer) for TEOAEs using either device (p = 0.105 to 0.810). A high concordance of NHS outcomes within-participants of 89.7 % and 85.0 % for DPOAE and TEOAE respectively, was measured.

CONCLUSIONS

The mHealth based OAE device demonstrated good agreement in NHS outcomes compared to a commercially available device. This verifies the performance of the novel smartphone based OAE device, and may facilitate increased accessibility of decentralised NHS service in resource constrained populations.

Genomic analysis of childhood hearing loss in the Yoruba population of Nigeria

Although variant alleles of hundreds of genes are associated with sensorineural deafness in children, the genes and alleles involved remain largely unknown in the Sub-Saharan regions of Africa. We ascertained 56 small families mainly of Yoruba ethno-lingual ancestry in or near Ibadan, Nigeria, that had at least one individual with nonsyndromic, severe-to-profound, prelingual-onset, bilateral hearing loss not attributed to nongenetic factors. We performed a combination of exome and Sanger sequencing analyses to evaluate both nuclear and mitochondrial genomes. No biallelic pathogenic variants were identified in GJB2, a common cause of deafness in many populations. Potential causative variants were identified in genes associated with nonsyndromic hearing loss (CIB2, COL11A1, ILDR1, MYO15A, TMPRSS3, and WFS1), nonsyndromic hearing loss or Usher syndrome (CDH23, MYO7A, PCDH15, and USH2A), and other syndromic forms of hearing loss (CHD7, OPA1, and SPTLC1). Several rare mitochondrial variants, including m.1555A>G, were detected in the gene MT-RNR1 but not in control Yoruba samples. Overall, 20 (33%) of 60 independent cases of hearing loss in this cohort of families were associated with likely causal variants in genes reported to underlie deafness in other populations. None of these likely causal variants were present in more than one family, most were detected as compound heterozygotes, and 77% had not been previously associated with hearing loss. These results indicate an unusually high level of genetic heterogeneity of hearing loss in Ibadan, Nigeria and point to challenges for molecular genetic screening, counseling, and early intervention in this population.

Emerging Data from a Newborn Hearing Screening Program in Sharjah, United Arab Emirates

Objectives

Newborn hearing screening (NHS) plays a critical role in early identification of hearing loss and subsequent early habilitation. Active parental involvement influences the success of NHS, particularly the initial NHS and follow-up. The current study reports the results of an NHS program in a cohort of babies born in a tertiary care hospital in Sharjah, United Arab Emirates (UAE). Further, it explores a two-stage NHS model to reduce false responses, thereby alleviating parental anxiety.

Methods

Retrospective observational study was conducted for a period of five years from January 2017 to December 2020. NHS was done as a two-stage model. All the healthy newborn babies were screened using Automated Auditory Brainstem Response (AABR) by trained audiology professionals. Babies who failed the first NHS were followed up after two weeks. Further, babies that failed the follow-up NHS were sent for diagnostic hearing evaluation and intervention as necessary.

Results

A total of 1821 newborn babies were screened during the study period. Eighty-one percent of babies passed the initial NHS. Four hundred and twenty-three (23.22%) babies were referred on the first NHS and were followed up after 2 weeks. Among these babies, 7.03% (24) failed second NHS. Nine (37.50%) of the 24 babies were confirmed to have hearing loss in both ears. The incidence of hearing loss in our cohort was 4.94 per 1000. Confirmed hearing loss was statistically higher in boys than girls (p < 0.05).

Conclusion

Current study was an attempt to report the emerging NHS data as part of the implementation of an NHS program. The study findings emphasize the need for a two-stage model of NHS to rule out false responses.

Hearing impairment detection and intervention in children from centre-based early intervention programmes

The study aimed to describe ages at identification and initiation of early intervention (EI) services for children enrolled in centre-based EI programmes in Gauteng, as well as to describe the nature of EI services that the children received. The researchers conducted retrospective record reviews of the EI programme files. In addition, caregivers of eight children identified with hearing impairments and enrolled in centre-based EI programmes in Gauteng completed a newly constructed questionnaire. The caregiver questionnaire produced data pertaining to the child's family demographics, background information and schooling history. Descriptive statistics were used to analyse the data, using frequency distribution and measures of central tendency. None of the children received newborn hearing screening services, thus they were identified late following maternal suspicion of hearing impairment. Late identification of the hearing impairment resulted in suboptimal initiation of EI services. All the children received aural habilitation and/or speech-language therapy services. These findings indicate that there is a great need for the establishment of widespread early hearing detection and intervention programmes that will lead to earlier identification of infant and childhood hearing impairment and timely initiation of EI services.

Prevalence of Hearing Impairment Among High-Risk Newborns in Ibadan, Nigeria

The burden of severe hearing impairment is increasing with two-thirds of these hearing impaired people residing in developing countries. Newborn hearing screening helps to identify early, babies who need intervention in order to prevent future disability. Neither universal nor targeted hearing screening programme is available in Nigeria. Objectives: This study was carried out to assess the prevalence of hearing impairment among high-risk newborns in UCH and the associated risk factors. Materials and Methods: Two hundred one newborns in the neonatal unit of UCH with risk factors for hearing impairment had hearing screening done using automated auditory brainstem response (AABR) at 30, 45, and 70 dB at admission and discharge, and those that failed screening at discharge were rescreened at 6 weeks post-discharge. Results: Eighty-three (41.3%) and 32 (15.9%) high-risk newborns failed at admission and discharge screening respectively, and 19 (9.5%) still failed at follow up screening. The majority of hearing loss at follow up was bilateral (94.7%) and severe (52.6%). The risk factors associated with persistent hearing loss at follow up were acute bilirubin encephalopathy (RR = 11.2, CI: 1.4-90.6), IVH (RR = 8.8, CI: 1.1-71.8), meningitis (RR = 4.8, CI: 1.01-29), recurrent apnoea (RR = 2.7, CI: 1.01-7.3), severe perinatal asphyxia NNE III (RR = 7, CI: 2.4-20.2). Conclusion: Severe and bilateral hearing impairment is a common complication among high risk newborns in UCH persisting till 6 weeks post-neonatal care. Severe perinatal asphyxia with NNE III, ABE, IVH, meningitis and administration of amikacin for more than 5 days were significant risk factors. We recommend that SCBU graduates with these risk factors should have mandatory audiologic evaluation at discharge.

Universal newborn hearing screening in southwestern Iran

OBJECTIVES

The implementation of Neonatal Hearing Screening (NHS) program is still at the preliminary stage particularly in developing countries despite the burden of permanent congenital and early-onset hearing impairment. The purpose of this study was to report results for universal newborn NHS in a cohort of children born in the southwestern region of Iran, as part of a national screening program set up by the Iranian National Health System.

METHODS

During this cross-sectional study, which took place between March 2013 and April 2016, healthy newborns were screened using transient evoked otoacoustic emissions (TEOAEs) and automated auditory brainstem responses (AABRs) methods at several points in time as early as possible after birth. Screening followed a two-stage strategy and newborns referred after the second-stage screening were scheduled for diagnostic evaluation.

RESULTS

A total of 92,521 newborns were screened in the urban (n = 67,780) and rural (n = 24,741) regions. Hearing impairment was confirmed in 223 (2.41 per 1000) newborns. One hundred forty-one (1.52 per 1000) of these newborns were affected bilaterally. More than 87% of these infants (195/223) showed a sensorineural hearing loss, while the defect was found to be conductive in 12 cases (P < 0.001). Of the 223 cases with hearing loss, 28 (12.5%) infants had auditory neuropathy. The majority of the infants, in both urban and rural regions, showed severe hearing impairment. We did not observe any significant difference among the incidences associated with gender (p = 0.29).

CONCLUSION

Our results demonstrated that universal newborn hearing screening program is an adequate program for southwestern of Iran with high coverage, low referral rate, and good follow-up rate.

Neonatal hearing screening: what we have achieved and what needs to be improved

OBJECTIVE

To review the literature on neonatal hearing screening and its weaknesses with regard to missed follow-ups and delayed diagnosis and management.

RESULTS

The implementation of newborn hearing screening programs has indeed lowered the mean age of hearing loss identification and many deaf children are now diagnosed at an early age of some months. However, the present collection of 32 studies published in the International Journal of Pediatric Otorhinolaryngology revealed that late-onset deafness, auditory neuropathy, and the alarming percentage of newborns who fail the initial testing and then are lost to follow-up are major weaknesses of neonatal hearing screening programs. It seems that parents may be satisfied of hearing screening but in a significant percentage of them do not bring their children for follow-up or further testing due to phycho-social or other reasons. In addition, the same collection revealed that socioeconomic factors may have a significant influence on the effectiveness of hearing screening programs in the developed and developing countries, where improvements in health care politics, tracking system and public awareness is crucial for successful program implementation.

CONCLUSIONS

Neonatal hearing screening programs have changed the whole picture of congenital deafness as age identification has significantly fallen with a very positive effect on timely management. However, the selected and proposed 32 related articles published in the International Journal of Pediatric Otorhinolaryngology show that there are still serious weakness in the neonatal hearing screening that need improvements in order to achieve an efficient and cost-effective system of deafness identification.

Common genes for non-syndromic deafness are uncommon in sub-Saharan Africa: a report from Nigeria

INTRODUCTION

Little is known about the molecular epidemiology of deafness in sub-Saharan Africa (SSA). Even in Nigeria, the most populous African nation, no genetic studies of deafness have been conducted. This pioneering work aims at investigating the frequencies of gene mutations relatively common in other parts of the world (i.e. those in GJB2, GJB6, and mitochondrial DNA) among subjects from Nigeria with hearing loss (HL) with no evidence of acquired pathology or syndromic findings. In addition, we review the literature on the genetics of deafness in SSA.

METHOD

We evaluated 81 unrelated deaf probands from the Yoruba tribe residing in Ibadan, a suburban city in Nigeria, for the aetiology of their deafness. Subjects underwent genetic testing if their history was negative for an environmental cause and physical examination did not find evidence of a syndrome. Both exons of GJB2 and mitochondrial DNA flanking the 1555A>G mutations were PCR-amplified followed by Sanger sequencing. GJB6 deletions were screened via quantitative PCR.

RESULT

We identified 44 probands who had nonsyndromic deafness with no environmental cause. The age at study time ranged between 8 months and 45 years (mean=24 years) and age at onset was congenital or prelingual (<age 2 years) in 37 (84%) probands and postlingual in 7 (16%) probands. Among these, 35 probands were the only affected members of their families (simplex cases), while there were at least two affected family members in nine cases (multiplex). Molecular analyses did not show a pathogenic variant in any one of the 44 probands studied.

CONCLUSION

GJB2, GJB6 and mitochondrial DNA 1555A>G mutations were not found among this initial cohort of the deaf in Nigeria. This makes imperative the search for other genes in the aetiology of HL in this population.