Epidemiology of hearing impairment at three Flemish Institutes for Deaf and Speech Defective Children

Impact of Universal Newborn Hearing Screening on cochlear implanted children in Ireland

OBJECTIVES

Cochlear Implant (CI) is an established treatment for severe to profound hearing loss (HL). Early diagnosis and intervention in HL are crucial in order to provide access to sound and increase the likelihood of spoken language development in pre-lingually deaf children. In April 2011, the Health Service Executive (HSE) implemented the Universal Newborn Hearing Screening (UNHS) in a phased regional basis in Ireland. This study aimed to investigate the general clinical pathway for UNHS referrals to the CI service and to evaluate the impact of earlier referrals via UNHS on functional outcomes in children.

METHODS

The first part of this study constituted a retrospective review of 100 children referred to the National Hearing Implant and Research Centre (NHIRC) via UNHS from November 2011 to December 2016. Implanted children referred via UNHS were categorised into three groups according to their medical status. Their clinical pathway to cochlear implantation was evaluated. Functional outcomes were investigated based on medical and developmental status, respectively. In the second part of this study, developmentally healthy implanted children referred post-UNHS were compared with medically healthy children referred pre-UNHS under the age of four, from January 2005 to June 2011. Current implant status of children, age at referral and functional outcomes were investigated.

RESULTS

Medically healthy children were referred to the NHIRC at an earlier age than the medically complex children (2.8 months vs 5.2 months, p < 0.01) and the children presenting with auditory neuropathy spectrum disorder (ANSD) (2.8 months vs 5.3 months, p < 0.01). On average they attended their first appointment and were implanted at a younger age than the ANSD group (6.1 months vs 10.1 months, p < 0.01; 16.3 months vs 29.4 months, p < 0.001, respectively). Developmentally healthy children had significantly better functional outcomes than children with developmental delays. Children referred via UNHS were referred and implanted at a younger age than those referred pre-UNHS. The former group achieved better Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores 2 years post-implantation.

CONCLUSION

UNHS in Ireland is an important platform for earlier diagnosis and management of congenital HL and our results show that early intervention has a positive impact on functional outcomes in children.

Aetiology of congenital hearing loss: a cohort review of 569 subjects

OBJECTIVE

Newborn hearing screening was implemented in Flanders about fifteen years ago. The aim of this study was to determine the aetiology of hearing loss detected by the Flemish screening programme.

METHODS

From 1997 to 2011, 569 neonates were referred to our tertiary referral centre after failed neonatal screening with Auditory Brainstem Responses. In case hearing loss (HL) was confirmed, further diagnostic testing was launched. A retrospective chart review was performed analysing the degree of HL, risk factor and aetiology.

RESULTS

Metabolic disorders (0.5%), infectious diseases (35.8%), congenital malformations (6.1%) and genetic abnormalities (19.8%), whether or not syndromic, were retained. In 35% of the subjects no obvious aetiology could be determined in the current study.

CONCLUSION

In contrast to the literature findings, this series shows a genetic syndromic cause in 80% of the genetic bilateral HL cases. On the other hand connexin positive diagnoses were mostly underrepresented in this study, showing the need for better screening.

Detection of perinatal cytomegalovirus infection and sensorineural hearing loss in belgian infants by measurement of automated auditory brainstem response

Since auditory disability causes serious problems in the development of speech and in the total development of a child, it is crucial to diagnose possible hearing impairment as soon as possible after birth. This study evaluates the neonatal hearing screening program in Flanders, Belgium. The auditory ability of 118,438 babies was tested using the automated auditory brainstem response. We selected 194 babies with indicative hearing impairment and 332 matched controls to investigate the association between the presence of human cytomegalovirus (HCMV) in urine samples and sensorineural hearing loss and to analyze the sensibility and specificity of a cell culture assay and a quantitative PCR detection method. Our results indicate that significantly more babies with confirmed hearing impairment were HCMV positive after birth. Further, based on the results of our study, babies with HCMV viral loads above 4.5 log copies/ml urine seem to be 1.4 times more likely to have confirmed hearing impairment. Our follow-up study suggests that the hearing impairment of children infected with HCMV after birth is less likely to improve than that of HCMV-negative infants. Our results confirm that the presence of HCMV before or shortly after birth influences the outcome of hearing impairment.

Etiologic and audiologic evaluations after universal neonatal hearing screening: analysis of 170 referred neonates

OBJECTIVE

The goal was to clarify the audiologic aspects and causes of congenital hearing loss in children who failed universal neonatal hearing screening.

METHODS

A prospective analysis of 170 consecutive records of neonates referred to a tertiary center after universal neonatal hearing screening failure, between 1998 and 2006, was performed. The data presented here represent the equivalent of approximately 87000 screened newborns. The screening results were validated with a clinical ear, nose, and throat examination and electrophysiological testing, including diagnostic auditory brainstem response, automated steady state response, and/or behavioral testing. A diagnostic evaluation protocol for identification of the cause of the hearing loss was also implemented, in collaboration with the departments of genetics and pediatrics.

RESULTS

Permanent hearing loss was confirmed in 116 children (68.2%). Bilateral hearing loss was diagnosed in 68 infants (58.6%) and unilateral hearing loss in 48 infants (41.4%). Median thresholds for the neonates with confirmed hearing loss were severe in both unilateral and bilateral cases, at 70 dB nHL and 80 dB nHL, respectively. In 55.8% of those cases, no risk factors for hearing loss were found. In 60.4%, the initial automated auditory brainstem response diagnosis was totally in agreement with the audiologic evaluation results. In 8.3% of the cases, however, a unilateral refer result was finally classified as bilateral hearing loss. An etiologic factor could be identified in 55.2% of the cases. Of the causes identified, a genetic mechanism was present in 60.4% of the cases, peripartal problems in 20.8%, and congenital cytomegalovirus infection in 18.8%.

CONCLUSIONS

An etiologic factor could be identified for nearly one half of the children with confirmed congenital hearing loss referred through a universal hearing screening program.

Impact of early hearing screening and treatment on language development and education level: evaluation of 6 years of universal newborn hearing screening (ALGO) in Flanders, Belgium

OBJECTIVES

Early intervention in hearing-impaired children may improve language outcomes and subsequent school and occupational performance. The objective of this study was to retrospectively analyze over 6 years the educational outcome and language development of a first cohort of children, detected by the Flemish universal newborn hearing screening (UNHS) program based on automated auditory brainstem response (AABR), with the oldest children being in primary school.

METHODS

We studied 229 hearing-impaired children from 1998 till 2003. The following variables were considered: the age during the school year 2005-2006, the degree of hearing loss, additional impairments including presence of intellectual disability, school placement and early intervention.

RESULTS

Analysis showed that 85.4% of the children with moderate, severe or profound hearing loss and no additional disability, older than 5.5 years, reach mainstream education. Further detailed description was provided for the outcomes of children with uni- and bilateral cochlear implants. Overall results stress that 46% of all children with a cochlear implant obtain mainstream education. Of all cochlear implant (CI) children above 5.5 years, without additional handicaps, 78.9% of children attend primary mainstream school. Data on language development show that up to 45% of the children with unilateral cochlear implant and no additional disabilities had normal to slight delay on language development. These data are fulfilling the goals stated by the JCIH and the American Academy of Pediatrics (AAP) in 2000. The role and impact of additional handicaps is discussed. The importance of early hearing loss identification and hearing therapy for appropriate language development is highlighted. Finally our preliminary results on children with bilateral cochlear implants without additional handicaps present an improved language development in comparison to unilateral CI-children.

CONCLUSION

A vast majority of the children detected by the UNHS program, with moderate, severe or profound hearing loss and no additional disability, older than 5.5 years, reach mainstream education. Additional disabilities have a major influence.

Effectiveness of population-based newborn hearing screening in England: ages of interventions and profile of cases

OBJECTIVE

The objective of this study was to determine the effectiveness in routine practice of the first phase of a national population-based newborn hearing screening and follow-up program that seeks to identify infants with bilateral permanent hearing loss of > or =40-dB hearing loss.

METHODS

The study was a part of the independent evaluation of the 23 first phase sites (annual birth population approximately 120,000) of the national newborn hearing screening program in England. For each infant identified with the defined hearing loss, the measures of interest were degree and type of hearing loss, presence of risk factors, age of first audiologic assessment, age of identification of hearing loss, age of enrollment in an early support program, and age of hearing aid fitting. Data collection took place over the first 2 years of the program.

RESULTS

Data were provided on 169 infants with permanent bilateral moderate or greater hearing loss identified through screening 169487 infants. Fifty-four percent of all cases were from an "at-risk" population. Three fourths of these "at-risk" infants spent > or =48 hours in the NICU. For the whole sample, the median age at first audiologic assessment was 5 weeks; the median age of identification of the hearing loss and of enrollment in early support program was 10 weeks irrespective of the degree of hearing loss; and the median age at hearing aid fitting was 16 weeks. Infants with moderate hearing loss were fitted with hearing aids significantly later than those with severe and profound hearing loss.

CONCLUSIONS

Properly implemented, a newborn hearing screening program based on whole populations and routine service provision can deliver satisfactory outcomes in terms of age of referral, identification, and intervention. The distribution of degree and type of hearing loss and proportion with risk factors was similar to that expected. The numbers identified were such as to suggest that very few cases were missed by the screening program.

Idiopathic sudden sensorineural hearing loss in children

OBJECTIVE

Although idiopathic sudden sensorineural hearing loss (ISSHL) is a frequent disease in adults, less is known about incidence and treatment of ISSHL in children.

METHOD

A retrospective chart analysis was performed to evaluate the frequency of ISSHL in children aged under 18 years between 2000 and 2003, who were treated in our department. Children received prednisolone intravenously at an initial dose of 3mg/kg bodyweight. Prednisolone dose was reduced to half every second day. The medication was given for a maximum of 14 days or finished 2 days after the hearing normalized in pure-tone audiometry. The follow-up was continued between 3 and 14 months.

RESULTS

The complete recovery rate was 57%, and the partial recovery was 36%. Initial hearing loss of 50dB and more was predictive for poor outcome in children (p=0.028). Presence of tinnitus was without relevance for the outcome. The incidence of ISSHL in the local area of about 250,000 inhabitants was 1/10,000 in children.

CONCLUSION

ISSHL seems to be a less frequent disease in children than in adults. Severe initial hearing loss is coupled with poor outcome. Under treatment with prednisolone hearing improvement was found in 13 of 14 patients.