The Health Professions Council of South Africa (HPCSA) issued early hearing detection and intervention guidelines, which has universal newborn hearing screening (UNHS) as one of the important goals. Despite established evidence of the importance of UNHS globally, there has been no mandated formalised and standardised implementation as yet in South Africa.
The aim of this study was to describe the outcomes of newborn hearing screening (NHS) in an academic secondary level hospital in Johannesburg, South Africa.
This was a prospective non-experimental feasibility study over a 3-month period, involving conducting hearing screening of 121 neonates. Audiologists conducted a risk factor assessment, otoscopic examinations and distortion product otoacoustic emissions (DPOAEs) screening on each neonate, with follow-up appointments for re-screening and diagnostic audiological assessments for all neonates with
Of the 121 neonates screened, the majority (75%) were screened in the first 24 h of life. A high
Findings contribute towards the existing evidence base that raises implications for successful implementation of NHS programmes in public healthcare in South Africa. Screening protocols need to consider the timing of screening, the measures and procedures adopted in the screening protocols, as well as the follow-up strategies.
The low- and middle-income world, where South Africa is located, is reported to be home to two-thirds of the world’s children with hearing impairment (Olusanya, Luxon, & Wirz,
Currently, there remains a paucity of sufficient evidence regarding the current status of neonatal hearing screening programmes in South Africa both in the public and private healthcare sector. The available evidence indicates limited success with implementation of these programmes within the South African context (Maluleke, Khoza-Shangase, & Kanji,
Universal newborn hearing screening (UNHS) is when every newborn baby is screened for hearing impairment at birth. Currently, in South Africa, no legislation exists to implement UNHS and because of resource constraints, the approach to NHS has been targeted screening (HPCSA,
Evidence suggests that in South Africa, where different types and levels of healthcare exist, NHS programmes have neither been standardised, nor have they been uniformly or universally implemented nationally (Khoza-Shangase & Kanji,
Another recent study from the South African context which explored factors associated with follow-up return rate in a risk-based NHS programme found that addressing the challenges to implementation of NHS is imperative towards successful EHDI (Kanji & Khoza-Shangase, 2018b). In this study, 66.5% of the participants returned for repeat screening, and this follow-up return rate decreased to below 50% for follow-up diagnostic assessment. Various reasons for poor return rate were identified, with one of the key challenges contributing to nonattendance being changes in residential location. The authors suggest that strategic bookings of appointments for screening where there is improved alignment of hearing screening appointments with other medical follow-up services are key to successful implementation of neonatal screening (Kanji & Khoza-Shangase, 2018b).
Other factors influencing successful implementation of hearing screening within the South African context, particularly UNHS, include the insufficient number of audiologists available to provide screening, the high rate of false positive test results and the high rates of loss to follow-up (Bezuidenhout, Khoza-Shangase, De Maayer, & Strehlau,
Regardless of hearing impairment being placed low on the government’s priority list, sufficient evidence exists to support the importance of identifying it early and providing intervention by 6 months of age (HPCSA,
This study was part of another study programme titled ‘Universal Newborn Hearing Screening in Public Healthcare in South Africa: Challenges to Implementation’ (Bezuidenhout et al.,
The study population was drawn from all neonates born at Rahima Moosa Mother and Child Hospital (RMMCH), an academic secondary level hospital in Johannesburg, South Africa, using stratified systematic sampling. Selected neonates from the postnatal wards, the neonatal unit and neonatal intensive care unit (NICU) were assessed during a 3-month period.
Because of the limitation of availability of only one audiologist to screen the babies, a task they took on in addition to their clinical caseload, a stratified sample of neonates was recruited. At the time of the study, the hospital had a delivery rate of 20–30 babies a day, with a Caesarean section rate of 30%. By selecting 30% of the neonates to be tested from the Caesar theatre birth register and the remaining 70% from the labour ward register, a representative sample of the delivery profile specific to the testing hospital was ensured. A total of 10 neonates were identified every day to be screened, by selecting every third neonate appearing on the registries. This stratified, systematic sampling was done at the start of each weekday by the researcher, who assigned a study number to each of the pre-identified neonates requiring screening.
Any neonate born at RMMCH within the specific 3-month period.
At the time of screening, infants were to be younger than 30 days of chronological age to minimise the influence of extraneous variables such as hearing loss because of other causes, as well as residential location changes.
Neonates who spent more than a month in NICU were excluded as they would have exceeded the age cut-off of 1 month.
Any neonate whose parent/caregiver refused to provide informed consent.
Neonates not born at the hospital site (transferred from other facilities).
Hearing screening took place at the secondary academic hospital during weekday working hours by the audiology department team, comprising four audiologists who are registered with the HPCSA as being qualified to conduct all measures included in this study a part of their regulated scope of practice. One audiologist was assigned to screen each day, and this audiologist would receive a list of 10 names from the researcher and would attempt to screen as many neonates as possible from the list. The audiologist would explain the purpose of the screening to the caregiver, both verbally and via an information sheet. If the caregiver was in agreement, written informed consent was obtained prior to the hearing screening. Once informed consent had been obtained, the audiologist would note the starting time so that the duration of the screening process could be recorded.
Each neonate who was screened first underwent an otoscopic examination to assess patency of the ear canal as this could potentially impede the screening procedure and impact the results. Thereafter, distortion product otoacoustic emission (DPOAE) screening was conducted through the use of a Natus Bio-logic AuDX® device, giving either a ‘pass’ or ‘refer’ result. For contextual relevance, although inclusion of automated auditory brainstem response (AABR) audiometry would have been ideal and is an important part of a two-stage screening protocol, AABR is not readily available in most South African healthcare contexts, but OAEs are becoming increasingly so (Kanji & Khoza-Shangase,
Babies receiving a ‘pass’ result were discharged without a planned follow-up, unless follow-up was clinically indicated. It is acknowledged that discharging a baby after a
Healthy neonates were screened within the first few days of life, whilst neonates with complications preventing earlier screening were screened when possible within the first 30 days of life. The neonates’ clinical history was obtained in all cases prior to the screening. This was obtained both verbally from the parent through an informal interview once consent had been given and by obtaining information documented in the neonate’s hospital file. A study data sheet was completed for each neonate that was screened. The study data sheet comprised three sections which included general information of the baby, the presence of risk factors and the findings on clinical assessment.
Firstly,
Data were entered into Microsoft Office Excel©, and later analysed using STATA intercooled version 11© (StataCorp,
The study adhered to the Singapore Statement on Research Integrity guidelines in terms of research into human subjects (Lucas,
During the 3-month study period, 2740 neonates were born at RMMCH, with a total of 490 neonates being identified and assigned study numbers. Of the identified neonates, two mothers refused consent for their infants to be screened. Because of the challenges discussed in Bezuidenhout et al. (
Time when hearing screening occurred in the current sample (
Otoscopic examinations revealed a large majority, 86 (71%) neonates, had vernix caseosa in their external auditory canals, and 39 (32%) were subjectively considered to have narrow ear canals (
Otoscopic findings in neonates prior to hearing screening (
The occurrence of a narrow ear canal was a subjective finding identified on otoscopic examination in 39 cases; 18 (46.2%) of which required a repeat DPOAE testing versus 39 (47.6%) of those without a narrow canal (odds ratio [OR]: 0.86, 95% confidence interval [CI]: 0.46–1.61,
Ear canal clearance was not performed on the participants because the study was meant to reflect the reality of the screening context. However, without artificial intervention, the high prevalence of vernix caseosa in the external auditory canal and its well-documented impact on OAEs raises important implications for the practicing audiologists and/or anyone involved in hearing screening, particularly in the first 24 h of life (Doyle, Rodgers, Fujikawa, & Newman,
Of the total sample, 57 of the 121 participants (47%) had a
The two infants that were to be referred for diagnostic ABR measurements could not be tested because of technical issues with the ABR equipment. This resulted in a third DPOAE being conducted on the one infant who returned for the follow-up. This infant passed DPOAEs bilaterally, whilst the second infant defaulted follow-up. The rate of true versus false positive results could not be determined in the current sample. This is another important finding for this context where loss to follow-up can negatively influence the outcomes of an already compromised hearing screening programme.
Repeat testing was required for 57 (47%) neonates; however, only 20 infants returned for repeat DPOAE. This referral rate of 47% after initial screening is much higher than the HPCSA’s recommendation of <5% (HPCSA,
Of the total sample of neonates screened, two (1.7%) had been admitted to NICU and both had required assisted ventilation. The first neonate had an NICU stay of 6 days and passed the initial DPOAE which was conducted on day 7 of life. The second neonate was admitted to NICU for 8 days and was considered high risk for a possible hearing deficit as several risk factors were identified, namely:
a positive family history (the maternal uncle) of permanent childhood hearing impairment
the presence of a congenital syphilis infection
intermittent positive pressure ventilation in NICU for 6 days
postnatal exposure to aminoglycoside antibiotics.
In this neonate, the initial DPOAE result was that of a bilateral
Other risk factors identified in the screened population included a family history of a permanent childhood hearing loss recorded in 10 (8.3%) neonates. Four of the neonates with a positive family history had a
Exposure to ototoxic medications in the form of aminoglycosides was recorded in three (2.5%) neonates in the screened cohort. One of these neonates with ototoxic drug exposure required a repeat DPOAE, which was successfully passed.
One neonate born at full term with a birthweight of 2.8 kilograms (kg) had a raised bilirubin level of 332 micromole per litre (µmol/L) at 72 h of life. According to the NICE guidance for neonatal jaundice, phototherapy was all that was required as the management (NICE Guidance,
Outcome groups on initial distortion product otoacoustic emissions screening and recorded risk factors.
Variable | ‘Passed’ screening test ( |
Requiring repeat DPOAE ( |
Total screened ( |
||||
---|---|---|---|---|---|---|---|
% | % | % | |||||
Admitted to NICU | 1 | 1.5 | 1 | 1.7 | 2 | 1.6 | 0.99 |
Family history of permanent childhood hearing loss | 6 | 9.3 | 4 | 7 | 10 | 8.2 | 0.75 |
Exposure to ototoxic drugs | 2 | 3.1 | 1 | 1.7 | 3 | 2.4 | 0.99 |
Hyperbilirubinemia | 0 | 0 | 1 | 1.7 | 1 | 0.8 | 0.47 |
Congenital infection | 0 | 0 | 1 | 1.7 | 1 | 0.8 | 0.47 |
HIV exposure positive | 15 | 23 | 14 | 24.5 | 29 | 24 | 0.99 |
HIV, human immunodeficiency virus; NICU, neonatal intensive care unit; DPOE, distortion product otoacoustic emissions.
Findings depicted in
Although current screening findings indicate no significant relationship between the
Findings from this study revealed challenges with conducting a NHS programme in a South African academic secondary level mother and child hospital. Current findings were influenced by three key factors: (1) the capacity versus demands in as far as insufficient number of audiologists available to provide hearing screening at the facility, (2) the high rate of false positive test results which were influenced by vernix as well as the fact that only one-stage screening protocol was used and (3) the unacceptably high rates of loss to follow-up (Bezuidenhout et al.,
The findings of this study raise implications for the implementation of NHS programmes in the South African context. Firstly, the staffing challenge needs to be addressed by possibly increasing the working hours of audiologists in the public healthcare sector to include evenings and weekends as babies are born and discharged during these times too. This is particularly important in a mother and child hospital facility. This, on its own, will not address the capacity versus demand challenge. However, when used in conjunction with task shifting this may significantly increase screening coverage. Because of the limited number of audiologists in the country, non-audiologists (including volunteers and/or nurses) should be trained to be screeners with supervision provided by audiologists in this task-shifting model of care. Secondly, as part of the screening programme, removal of vernix caseosa from the external auditory meatus needs to be done routinely in order to ensure that this does not become a confounding variable in the screening findings. This is particularly important as often otoscopic examination does not routinely form part of standard screening protocols. Because of the early discharge and the high likelihood of the presence of vernix caseosa within the South African context, inclusion of otoscopic examination in the screening protocol has been demonstrated to be important. Thirdly, repeat screening for all neonates with
Current findings must be interpreted taking into consideration the identified methodological limitations. The 3-month time period used for data collection was the main limitation of the study. It is believed that a longer time frame where other variables could have come into play might have influenced the findings of the study (Bezuidenhout et al.,
The authors would like to acknowledge Rahima Moosa Mother and Child Hospital speech therapists and audiologists who conducted the hearing screening.
The authors have declared that no competing interest exists.
J.K.B., K.K.-S. and T.D.M. designed the study and analysed the data. All authors were involved in the writing of the manuscript.
This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Data sharing is not applicable to this article as no new data were created or analysed in this study.
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of any affiliated agency of the authors.