Epidemiology of Permanent Childhood Hearing Impairment in Estonia, 1985-1990: Epidemiologia de los trastornos auditivos permanentes de la infancia en Estonia (1985–1990)

Postnatal hearing loss: a study of children who passed neonatal TEOAE hearing screening bilaterally

BACKGROUND

Universal newborn hearing screening (UNHS) contributes to the early diagnosis of hearing loss. However, not all permanent pediatric hearing impairments can be identified by UNHS.

AIMS/OBJECTIVE

To investigate children who have successfully passed the UNHS, but have later-onset hearing loss at an early stage.

METHODS

UNHS of children, was reviewed retrospectively from databases at Karolinska University Hospital, Sweden. Gender, age, the reason for contact, the first contact and the most recent audiogram, the hearing diagnosis, the degree of hearing loss when they were enrolled in hearing rehabilitation, and the hearing aids they used were analysed.

RESULTS

63 children who had passed the UNHS at birth and were diagnosed with a hearing impairment at a later stage were included in the study. The average age was 3.3 and 3.9 years old when the children were diagnosed and were finally enrolled in the hearing habilitation, respectively. The reasons for diagnostic evaluation of a suspected hearing loss at present study are preschool hearing tests at the Child Health Care Centres, parents suspect, and/or delayed speech and language development.

CONCLUSIONS AND SIGNIFICANCE

Our findings suggest that a passed UNHS does not exclude a future delayed onset of hearing loss, particularly in children with risk factors.

Hearing difficulties in children with special health care needs

OBJECTIVE

To determine characteristics of children with special health care needs (CSHCN) with hearing difficulties including patterns of hearing aid use, comorbidity, and social and communication function.

METHODS

Bivariate and multivariable analysis of cross-sectional data on 40,723 children aged from birth to 17 years from the 2005-2006 National Survey of Children with Special Health Care Needs, including 1,982 (5%) with parent-reported hearing difficulties.

RESULTS

Among CSHCN, 383 (1%) used hearing aids, representing 20% of those with reported hearing difficulties. Odds of hearing aid use increased with age, primary language other than English, and lower income. More than half (58%) of the aided children reported hearing difficulties even with their aid. Among CSHCN with cerebral palsy, 13% had reported hearing difficulties and 3% used hearing aids. Equivalent figures for children with Down syndrome were 24% and 4%, mental retardation/developmental delay 12% and 5%, and autism spectrum disorder 9% and 2%. Overall, two-thirds of CSHCN with hearing difficulties had one or more sensory/developmental comorbidities; CSHCN with both hearing difficulties and a sensory/developmental comorbidity had highest odds of learning difficulties, speaking/communication difficulties, feeling anxious/depressed, acting out/bullying, and difficulty making friends. CSHCN with hearing difficulties alone, or sensory/developmental conditions alone had intermediate odds, after socio-demographic adjustment.

CONCLUSIONS

Sensory/developmental comorbidities are common among CSHCN with hearing difficulties, and they are associated with higher odds of poorer social, communication, and educational function. Services for CSHCN must be equipped to address a range of hearing difficulties as well as sensory/developmental comorbidities and to improve social/emotional functioning as well as learning and communication.

Causes of permanent childhood hearing impairment

INTRODUCTION

The causes of Permanent Childhood Hearing Impairment (PCHI) are often quoted as being hereditary in 50%, acquired in 25%, and unknown in 25% of cases. Interest in the causes of PCHI has grown recently due to increasing diagnostic possibilities. We investigated the evidence for the reported distribution of these causes.

METHODS

Population-based study and a systematic review. Inclusion criteria for population-based study: children born between 2003 and 2005, resident in The Netherlands at birth, known at an Audiology Center with PCHI at the age of 3-5 years. The causes of PCHI were determined prospectively by detection of congenital cytomegalovirus on dried blood spots and/or genetic diagnostic investigations in addition to reviewing data from medical records. A systematic review was carried out using three terms (hearing loss, infant, and etiology) and limited to articles published between January 1997 and July 2009. Main outcome measures were: the (weighted) proportions of the various causes of PCHI following diagnostic investigations.

RESULTS

In the study-population (n = 185) a hereditary cause was found in 38.9%, acquired cause in 29.7%, miscellaneous cause in 7.1%, and the cause remained unknown in 24.3%. The systematic review of the literature (n = 9 articles) resulted in a weighted mean of 30.4% hereditary, 19.2% acquired, and 48.3% unknown causes of PCHI.

DISCUSSION

The systematic review and the results of the population-based study provided little support for the generally accepted distribution of causes of PCHI.

Prevalence and etiology of congenital or early acquired hearing impairment in Eastern Finland

OBJECTIVE

The purpose of this study was to determine the prevalence and etiology of congenital or early acquired bilateral sensorineural hearing impairment (SNHI) in children born from 1988 to 2002 in the district of Kuopio University Hospital, Finland, and to compare the results with those from an earlier 14-year period in the same region and similar population.

METHODS

The data were collected retrospectively from Hospital Records. The degree of hearing impairment was based on average air conduction threshold calculated over the frequencies 0.5, 1, 2 and 4 kHz in the better hearing ear. Hearing impairment was classified as mild (≥ 20-39 dB), moderate (40-69 dB), severe (70-95 dB) and profound (>95 dB).

RESULTS

We identified 92 children with bilateral SNHI diagnosed before the age of 7 years. The overall prevalence and the prevalence for at least moderate SNHI was 2.1 per 1000 live births and 1.2 per 1000 live births, respectively. We found no differences in the prevalence of SNHI during both study periods. Etiology was genetic in 46%, acquired in 14% and unknown in 40%. Out of the genetic cases 74% were non-syndromic and 26% were syndromic. In comparison to the previous study there was a decline in the proportion of acquired SNHI and the proportion of genetic and unknown cause had increased. Six children in five families had homozygous 35delG mutation and six children in four families presented with a homozygous M34T mutation.

CONCLUSIONS

The prevalence of congenital or early acquired SNHI in the Kuopio University Hospital district area has not changed during a period of 29 years. Despite possibility to test the GBJ2 gene, the proportion of hearing impairment of unknown etiology remained high.

Epidemiology of congenital hearing loss in Victoria, Australia: Epidemiología de la hipoacusia congénita en Victoria, Australia

The aim of this study was to report the incidence, prevalence and clinical characteristics of congenital hearing loss sufficient to require hearing aid fitting in the first 6 years of life for the 1993 birth cohort of the state of Victoria (population 4.4 million), Australia. In 1993, 64,116 infants born in the state of Victoria survived the neonatal period. Subjects included all children with congenital hearing loss for which hearing aids were fitted, at any time up to and including 31 December 1999, when the youngest member of the cohort reached 6 years of age. Data on the degree, type and etiology of hearing loss were available from the Australian Hearing database for all subjects. Sociodemographic and health data were available from the Victorian Infant Hearing Screening Program (VIHSP) and parent questionnaires. The known prevalence of identified congenital hearing loss increased as the cohort aged. By the time the youngest member had reached the age of 6 years, 134 children (78 boys, 56 girls) had been fitted with hearing aids for permanent congenital hearing loss of any degree (2.09/1000). Fifty-four (40%) of these had known mild losses (20-40 dB HL). The prevalence of known moderate or greater loss (> 40 dB HL) was 1.12/1000; the data suggest that over 90% could have been detectable by neonatal hearing screening. A further seven children from the birth cohort were fitted with hearing aids due to acquired forms of hearing loss (0.11/1000). The etiology was known in only 57 (43%) congenital cases, with known non-syndromal genetic causes accounting for 21 (37%) of these. This study reports on the prevalence of congenital hearing loss requiring hearing aid fitting for an entire birth cohort. These data indicate the possible yield from neonatal screening, and hence the likely benefit of such screening. For a large proportion of cases, the etiology remains unknown. These data have implications for health service delivery and illustrate the usefulness of a population database in monitoring the prevalence of congenital hearing loss.

Estudo retrospectivo de crianças e jovens com deficiência auditiva: caracterização das etiologias e quadro audiológico

OBJETIVO: conhecer os fatores de risco para deficiência auditiva e obter informações sobre o tempo transcorrido entre suspeita, diagnóstico e intervenção em crianças e jovens deficientes auditivos atendidos no Serviço de Audiologia Educacional, DERDIC-PUC-SP. MÉTODOS: estudo retrospectivo de 162 prontuários de deficientes auditivos com idade entre um e 17 anos e 6 meses, atendidos de 1999 a 2002. Para registro dos dados utilizou-se a adaptação do protocolo elaborado no Fórum de Reabilitação Aural do Encontro Internacional de Audiologia, no Brasil. RESULTADOS: 54% dos sujeitos eram do sexo masculino e 46% do feminino; 60% tinham idade entre três e oito anos e 11 meses; 43% tiveram a suspeita da deficiência auditiva no primeiro ano de vida. Em 25% dos casos, o diagnóstico ocorreu logo após a suspeita, em 34% ocorreu um intervalo de até um ano; 11% iniciaram atendimento fonoaudiológico após diagnóstico, 54% demoraram até um ano e 27% demoraram mais de um ano. Trinta e dois por cento apresentaram etiologia desconhecida, 18% genética, 17% presumida multifatorial, 15% meningite, 9% rubéola congênita. CONCLUSÃO: a prevalência da etiologia desconhecida aponta para a necessidade do aprofundamento no diagnóstico etiopatológico (estudos genéticos, de imagens e laboratoriais) como rotina para se obter as causas da deficiência auditiva. Observou-se que mesmo após as campanhas de vacinação, a rubéola ainda foi a maior causa de deficiência auditiva congênita e a meningite a maior causa das deficiências auditivas adquiridas após o nascimento. Constatou-se um longo intervalo de tempo entre suspeita, confirmação e início da intervenção fonoaudiológica.

Challenges in management of childhood sensorineural hearing loss in sub-Saharan Africa, Nigeria

The evaluation of a hearing-impaired child attempts to determine the aetiology, the degree of hearing loss and intervention to aid speech and language. This remains a challenge to practising otolaryngologists, especially in the developing countries as 85-90% of causes of hearing losses were never discovered leading to delayed intervention and irreversible effects. In a review of children presenting at the otolaryngology outpatient in the University College Hospital, Ibadan, Nigeria, sensorineural hearing loss was found in 103, giving a hospital prevalence rate of 14%, we still perceived this figure to be unrepresentatively and low, probably due to poor access to medicare, poverty and other factors. Genetic factor accounted for 25%, followed by measles infections 13% and meningitis 8%. About 60% of them had educationally significant hearing loss at presentation. Access to hearing aid was poor as only 12.5% of the patients could afford it and the rest were managed by deaf training. We conclude by suggesting an audiologic programme which has the comprehensive function of neonatal and infant hearing screening, subsidized hearing aid services and hearing rehabilitation surgery.

Study of the hearing loss in children and adolescents, comparing the periods of 1990-1994 and 1994-2000

INTRODUCTION

In 1994, a study was performed with 200 children and adolescents suffering from hearing loss. It concluded that the diagnostic confirmation of hearing loss within 2 years of age occurred in just 13% of the cases, although 56% were suspected in that phase. The loss of time of over 2 years between suspicion and confirmation of hearing loss occurred in 42% of the cases.

OBJECTIVES

The comparison of the main hearing loss etiologies-genetic cause, consanguinity, congenital rubella, meningitis, perinatal events and unknown causes-in children and adolescents in the periods of 1990-1994 and 1994-2000; comparison of incidence, in males and females, for each etiology and among the others; comparison of age at the first consultation, for each and among them; and the investigation as to whether the time between suspicion and diagnosis of hearing loss was different for each etiology and among the others.

METHODS

During the period of 1990-2000, of the 519 children and adolescents with hearing loss, 442 individuals were selected, in the two moments of the study: 1990-1994 and 1994-2000. The variables used were: sex, age at first consultation, suspected etiology and time between suspicion and confirmation of hearing loss.

RESULTS

Congenital rubella, genetic and perinatal causes, meningitis, consanguinity and unknown causes were responsible for over 80% of all etiologies, in both periods. There were no differences between the sexes in the periods studied. There was no relation among age, sex and etiology. Among the etiologies studied, there were no differences in the lengths of times between suspicion and confirmation of hearing loss, in each period separately. The comparative study showed that congenital rubella, genetic and unknown causes took longer times between suspicion and confirmation of hearing loss, for the period of 1990-1994, as compared with 1994-2000.

CONCLUSIONS

Congenital rubella remains as an important etiology, as well post-meningitis deafness. Age at first consultation did not show relationship to the hearing loss etiology nor to sex. Independently of whether the etiology being pre-natal, perinatal or post-natal, congenital or acquired, the length of time between suspicion and confirmation of hearing loss did not differ between the periods studied, separately.

Benefits and challenges of newborn hearing screening for developing countries

The late detection of permanent congenital and early-onset hearing loss (PCEHL) often has severe effects on linguistic, speech, cognitive and educational development in affected children. Since newborn hearing screening (NHS) allows most PCEHL to be detected early enough for optimal intervention, the prospects of its introduction in the developing world are reviewed in this paper. It is observed that a simple generalisation on the feasibility of NHS for the developing countries seems inappropriate in view of the diversities in the health and socio-economic status of these countries and the recent favourable reports of universal newborn hearing screening from the region. NHS empowers parents to make timely choices that will allow their hearing impaired children to be given a good start in life and be fully integrated into the wider community. It also compels attention towards the development of essential hearing healthcare services, besides the specific documented benefits. Existing child-healthcare structures such as the expanded programme on immunisation (EPI), baby friendly hospital initiatives (BFHI) and integrated management of childhood illness (IMCI) provide opportunities for the introduction of some form of NHS in many of these countries where routine or systematic childhood hearing screening does not exist. Limited funding, manpower shortages, inadequate support services, low public awareness and the uncertainty regarding the commitment from healthcare practitioners may present some challenges but these are not insurmountable. Pilot studies are necessary in each country to provide empirical data that will guide healthcare providers who wish to introduce such a programme at any level of healthcare delivery.

Prevalence of hearing impairment in a population in Sweden

An epidemiological study was carried out, based on 590 randomly selected subjects, aged from 20 to 80 years, in the province of Ostergötland in Sweden. The results obtained were similar to published results from other countries, with an overall prevalence of subjects with average hearing threshold levels over the frequencies 0.5, 1, 2 and 4 kHz (M4) equal to or exceeding 25 dB HL for the better ear (BE) of 16.9% (95% CI: 13.819.9%). For M4 BE > or = 35 dB HL, the prevalence was 7.7% (95% CI: 5.5-9.8%), for M4 BE > or = 45 dB HL, the prevalence was 3.3% (95% CI: 1.9-4.8%), and for M4 BE > or = 65 dB HL, the prevalence was 0.2% (95% Cl: 0.0-0.6%). The overall prevalence of reported tinnitus was 13.2% (95% CI: 10.5-16.0%). In the population under study, 7.7% of the subjects were estimated to benefit from a hearing aid, while the prevalence of hearing aid users was 2.4%.

Birth weight and hearing impairment in norwegians born from 1967 to 1993

OBJECTIVES

To estimate the association between birth weight and hearing impairment among Norwegians born between 1967 and 1993, taking other pregnancy-related conditions into consideration.

METHODS

A cohort study was conducted of all Norwegian live births from 1967 to 1993 (n = 1 548 429) linking information of the Medical Birth Registry of Norway and the register for the National Insurance Administration, which covers all Norwegians. The Medical Birth Registry of Norway has recorded information on birth weight and other pregnancy-related conditions as well as diseases of the mother before and during pregnancy. The register of the National Insurance Administration contains information on all Norwegians who have received cash benefits for a disease/disability, including hearing impairment. Data up to 1997 are included; thus, the follow-up period varies between 29 and 3 years.

RESULTS

The occurrence of hearing impairment was 11 per 10 000, decreasing from 60 per 10 000 for birth weights <1500 g to 6 per 10 000 for birth weights >4499 g. Compared with birth weights between 3000 g and 3499 g, the adjusted rate ratio of hearing impairment was 7.55 (95% confidence interval: 4.81-11.87) for birth weights <1500 g and 0.50 (95% confidence interval: 0.34-0.73) for birth weights >4499 g. The association did not change substantially with adjustment for other pregnancy-related conditions. Restricting the analyses to term born, the association between hearing impairment and low birth weight became stronger.

CONCLUSIONS

Birth weight was a strong predictor of hearing impairment in the Norwegian population. Children who were born at term with a low birth weight seemed to be a particularly vulnerable group.

Epidemiology of the UK population of hearing-impaired children, including characteristics of those with and without cochlear implants--audiology, aetiology, comorbidity and affluence

This study reports epidemiological data for 17,160 children with permanent bilateral hearing impairment >40 dB in the UK in the birth cohorts 1980-95 inclusive. Children were uniquely ascertained from notifications from professionals in health and education. Results indicate a changing aetiological profile over birth cohort. The percentage of unknown aetiologies and those of prenatal or postnatal origin have decreased, while syndromal and perinatal aetiologies have increased, with no change in genetic aetiologies. Nearly 30% of hearing-impaired children have another disability in addition to their hearing impairment. Children with cochlear implants are more likely than other profoundly impaired children to have a postnatal aetiology and less likely to have disabilities concerned with learning or cognition. A proxy measure of affluence indicates that significantly more profoundly impaired children in more affluent families receive cochlear implants than do those in less affluent families. These findings provide baseline data for the UK population and raise questions of widespread relevance for future research.

Epidemiology of permanent childhood hearing impairment in the Tyrol, 1980-94

In recent years the need for reliable data on permanent childhood hearing impairment (PCHI) has increased, owing to both scientific interest and practical aspects such as implementation of neonatal hearing screening. In order to obtain data about the epidemiology of PCHI in the Austrian state of Tyrol, the medical records of all hearing-impaired Tyrolean children born between 1980 and 1994 were researched. A total of 165 children with at least moderate hearing impairment in the better ear were registered, of whom 52.7% were found to be moderately hearing-impaired, 24.2% severely hearing-impaired and 23.0% profoundly hearing-impaired. Sensorineural hearing loss was observed in 87.3%, conductive hearing loss in 6.7% and mixed hearing loss in 6.1%. As for aetiology, non-syndromic hereditary hearing loss was diagnosed in 22% of the children and syndromic hearing loss in 8%. Congenital malformation of the ear was found in 3%. In 19% of the children, perinatal risk factors were seen, and in 10% a pre-, peri- or postnatal infection had occurred. Aetiology remained unknown in 36% of the children. The prevalence rate of newborn hearing impairment was 1.27/1000 newborns. The results are considered to fit well to the PCHI findings reported from other European regions.