Article Text

Postneonatal care pathways and the identification of deafness
  1. Peter Watkin
  1. Correspondence to Dr Peter Watkin, Department of Audiology, Whipps Cross University Hospital, Whipps Cross Road, Leytonstone, London E11 1NR, UK; peter.watkin{at}whippsx.nhs.uk

Abstract

Background The need to maintain clinical pathways for the postneonatal identification of deafness was investigated following the successful implementation of universal newborn hearing screening.

Methods Identification routes were compared for 378 hearing impaired children ascertained from three 10-year cohorts: one that had not received neonatal screening, one that had received targeted neonatal screening and one that was universally screened. The presence of risk factors was determined in those with a hearing impairment.

Results The cohort comparison confirmed significant changes in the yield from all identification routes apart from referrals reactive to parental or professional concerns. In the cohort universally screened, this reactive yield was 1.23/1000 with 51% having risk factors for deafness. Universal newborn hearing screening did not reduce this postneonatal yield.

Conclusions Despite the successful implementation of newborn hearing screening, clinical pathways with access to audiological assessment need to be maintained within a universal Healthy Child Programme.

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Introduction

A 10-year cohort that received a universal neonatal hearing screen (UNHS) has been longitudinally followed up in the East London district of Waltham Forest. Maternity and paediatric services are provided by Whipps Cross Hospital where a two stage transient oto-acoustic emission screen was implemented as a UNHS for 10 years before being absorbed by the national Newborn Hearing Screening Programme (NHSP). The UNHS predicted the yield of 0.96/1000 with bilateral and 0.49/1000 with unilateral permanent childhood hearing impairment (PCHI) subsequently achieved by the NHSP. However, follow-up of the cohort found that the prevalence of PCHI had increased to 3.65/1000 by entry to primary school if all degrees of hearing impairment were included, with just over half of cases by this age having required postneonatal identification.1 The majority requiring postneonatal identification had been reactively referred because of parental or professional concerns, with a smaller number identified through the School Entry Screen (SES). These postneonatal clinical pathways are part of the Healthy Child Programme2 that has modernised the surveillance of child health. Evidence is required to support a continued need for postneonatal case finding now that neonatal hearing screening has been successfully implemented. The current study therefore compared identification of deafness following UNHS implementation with that when a targeted neonatal hearing screen (TNHS) was in place and when no neonatal hearing screen (NNHS) was available. The three programs were undertaken by the Whipps Cross Audiology Service and longitudinal evaluations of the cohorts have been reported until the end of the first school year.3 4 The combined cohort consisted of 100 096 children and comparison of the programs has been considered a valuable quasi-controlled indication of UNHS implications with comparisons with national epidemiological studies supporting the generalisability of the data.5

Methods

PCHIs were ascertained from the 10-year Waltham Forest cohort of 35 668 children who had received the UNHS from 1992 to 2002. Postneonatal identification was through child health surveillance with the universal Health Visitor Distraction Test (HVDT) replaced after 5 years by a targeted HVDT. The SES was retained. The Audiology Service received reactive and screening referrals with notification of PCHIs from all sources.

PCHIs identified by UNHS were compared with those from:

  1. A historical 10-year Waltham Forest cohort of 31 538 born between 1977 and 1987 when NNHS was available. PCHIs were identified by HVDT, reactive pathways, SES and for a short period a screen at 3 years of age employing a speech discrimination test.

  2. A 10-year cohort of 32 890 born between 1990 and 2000 in the neighbouring borough of Redbridge when a TNHS was in place. HVDT and SES were retained and referrals made to the Whipps Cross Audiology Service.

Congenital and late onset PCHIs were ascertained until the end of the first school year. Degrees of impairment were defined by averaging the hearing thresholds at the four octave frequencies between 500 and 4000 Hz (table 1). Moderate, severe and profound bilateral impairments are the NHSP target and were aggregated for some analyses. Identification routes were compared using Pearson's χ2 test. The ages when congenital PCHIs were confirmed following the neonatal screens were compared by the Kruskal–Wallis test. Those moving in to the area with previously identified deafness (n=30) were excluded from the comparisons. The possibility of PCHI identification through proactive referral by professionals of children with risk factors for deafness was investigated in those from the UNHS cohort who had required postneonatal identification.

Table 1

Prevalence of PCHI by the age of entry to primary school in the combined cohort of 100 096 with comparison of the three cohorts (total number of PCHIs in combined cohort=378)

Results

There were no significant differences in the prevalence rates of bilateral PCHI in the three cohorts (table 1). Of 2.75/1000 in the combined cohort with bilateral PCHI, 0.24/1000 (95% CI 0.14 to 0.34) had a late onset moderate or worse PCHI. This late onset group was comprised of eight children from the NNHS cohort, seven from the TNHS cohort and nine from the cohort that had received the UNHS. There was no significant difference between the cohorts in late onset prevalence (χ2=0.613, df=2, p=0.736). However, there was a significant reduction in severe and profound unilateral deafness, with 30 children with this degree of impairment in the NNHS cohort (prevalence of 0.95/1000, 95% CI 0.61 to 1.29) falling to 15 in the TNHS cohort (prevalence of 0.46/1000, 95% CI 0.23 to 0.69) and 14 in the cohort that had received the UNHS (prevalence of 0.39/1000, 95% CI 0.19 to 0.6) (see online supplementary table A1).

Comparison of the cohorts confirmed significant changes in the yield from all identification methods (p<0.05) with the exception of reactive referrals above 1 year of age (see online supplementary table A2 and figure 1). The reactive yield after infancy was 1.33 (95% CI 0.93 to 1.73) from NNHS, 1.06 (95% CI 0.71 to 1.42) from TNHS and 1.12 (95% CI 0.77 to 1.47) from UNHS (χ2=1.09, df=2, p=0.579). In the UNHS cohort, the overall yield of 1.23/1000 from reactive referrals combined for infancy and early childhood was four times the SES yield of 0.31/1000 (95% CI 0.13 to 0.49) and 69% the neonatal yield of 1.79/1000 (95% CI 1.36 to 2.23). Reactive referrals were from health visitors or community nurses (34%), paediatricians (31%), general practitioners (16%), speech therapists (15%) and others (<5%). When the yield from neonatal tests was excluded, the ages at confirmation of congenital PCHIs had not significantly improved, with median ages of 218 weeks from NNHS, 210 weeks from TNHS and 219 weeks following UNHS (Kruskal–Wallis χ2=0.436, df=2, p=0.804).

Figure 1

The methods of identification of permanent childhood hearing impairment (PCHI) present in primary school in the cohort when no neonatal screen was available (NNHS), the cohort which received a targeted neonatal screen (TNHS) and the cohort which received the universal neonatal screen (UNHS) excluding those moving in to the area with previously identified deafness (n=348). HVDT, Health Visitor Distraction Test; SES, School Entry Screen.

Of the 130 primary school children with a PCHI in the cohort that had received the UNHS, nine had moved into the district with an already known PCHI. Of the 121 requiring identification in Waltham Forest, 57 (1.60/1000) had required this after the neonatal hearing screen (online supplementary table A2) and were investigated for the presence of risk factors. Paediatric services provided long-term care for 14 (25%) with malformation syndromes or cranio-facial abnormalities (CFA) and for three (5%) with a developmental legacy of perinatal illness. An additional three (5%) had PCHI acquired from bacterial meningitis (0.08/1000). A known family history of childhood deafness allowed proactive identification in nine of 15 (26%) with familial deafness. Twenty nine of the 57 (51%) could therefore have been identified by proactive paediatric referral, giving an overall yield of 0.81/1000. Surveillance of all those defaulting UNHS attendance would have given an additional postneonatal yield of five children (0.14/1000).

Discussion

Despite the value of newborn hearing screening, it will only identify around half the PCHIs in primary school children and there remains a need for effective postneonatal case finding. Although only one third of the postneonatal yield have moderate or worse bilateral deafness targeted by NHSP, milder and unilateral cases suffer a disability and require postneonatal identification6 and parents want PCHI identified as early as possible irrespective of the degree.7 The HVDT is not worthwhile and SES validity requires evaluation. After UNHS, reactive referral prompted by parental or professional concerns makes the largest contribution to the yield of PCHIs identified in childhood, and this has not decreased following the introduction of neonatal screens. If the contribution made by the introduction of neonatal tests is disregarded, then the median age of confirmation of deafness has remained unchanged at over 4 years. There is therefore a need to maintain these clinical pathways and to improve them. Postneonatal identification could be made more proactive through risk factor referral and hearing surveillance throughout early childhood. Family history remains an important postneonatal risk factor with deafness associated with CFA or malformation syndromes identifiable by monitoring hearing as part of the routine care of these children. The main risk factor for acquired deafness remains bacterial meningitis. Yet proactive hearing surveillance has well-recognised operational limitations and optimally can only pick up around half the PCHIs needing postneonatal case finding. Postneonatal identification will remain dependent upon the interaction between parents and professionals and pathways which allow ready access to audiology services through a successful universal Healthy Child Programme.

References

Supplementary materials

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Footnotes

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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