Pre-school children with impaired hearing in Göteborg 1964-1980

Children With Unilateral Hearing Loss After Newborn Hearing Screening in Taiwan

PURPOSE

We explored the intervention characteristics and language outcomes of children with unilateral hearing loss (UHL) in Taiwan after the implementation of universal newborn hearing screening (UNHS) to highlight changes in attitudes and actions toward hearing-related treatments.

METHOD

Data of 132 children with UHL in birth cohorts from 2012 to 2019 were included. This retrospective study examined differences in age at identification, hearing aid (HA) fitting, and seeking supportive services. Commonly requested attributes of services, reasons for HA rejection, and children's language performance were investigated.

RESULTS

The age at identification decreased from 50.3 months in 2012 to 2.6 months in 2019. Similar trends of declining age were obtained for the age at HA fitting and age at first service contact. In addition, 40% of the parents did not seek support until the child became older (M = 30.5 months) and showed more noticeable behaviors related to hearing loss, and only 64% of the children were consistent HA users. Children with UHL enrolled in the intervention programs approximated the average language performance of the assessment norm; however, they showed depressed language levels when compared to the norm group at the 75th percentile.

CONCLUSIONS

UNHS had a positive impact on early identification and intervention in children with UHL. Compared to parents of children with all types of hearing loss, parents of children with UHL seemed to be more uncertain about aural habilitation at the early stage.

Hearing impairment among children in Sweden with foreign-born parents and natives: A national Swedish study

AIM

We aimed to estimate the risk of hearing impairment in children and adolescents with foreign-born parents, compared to natives.

METHODS

A nationwide study of 1,923,590 (51.4% boys) individuals aged 0-17 years of age in Sweden. Hearing impairment was defined as at least one registered diagnosis in the National Patient Register between 1 January 1998 and 31 December 2015. We used Cox regression analysis to estimate relative risk (hazard ratios with 99% confidence intervals) of incident hearing impairment in children with foreign-born parents compared to Swedish-born natives. Cox regression models were stratified by sex and adjusted for age, co-morbidities and socioeconomic status.

RESULTS

A total of 20,514 cases (53.7% boys) with extended sensorineural hearing impairment were registered, also including noise-induced hearing impairment and that from other causes, and 6172 cases (50.0% boys) with conductive hearing impairment. The risk of extended sensorineural hearing impairment was higher in boys with parents from Asia, especially from Iraq, fully adjusted HR (99% CI) 1.30 (1.17-1.4), and lower in boys with parents from Nordic countries, South Europe, and North America.

CONCLUSION

The risk of extended sensorineural hearing impairment was higher in boys with parents from Asia, in particular Iraq.

Temporal bone high-resolution computed tomography in non-syndromic unilateral hearing loss in children

OBJECTIVE

The aim of this study was to disclose possible inner ear abnormalities/pathologies by means of high-resolution computed tomography (HRCT) of the temporal bone (TBHRCT) in children with unilateral hearing loss (UHL).

METHODS

Retrospective review of audiological evaluation and TBHRCT in 22 children with UHL.

RESULTS

Two thirds of the children showed profound hearing loss. Review of HRCT scans identified inner ear malformations/pathologies in 9 (41%) cases and a high jugular bulb (HJB), always dehiscent with the vestibular aqueduct, in another 5 (22%). Inner ear malformations included enlarged vestibular aqueduct, common cavity and cochleovestibular hypoplasia, while labyrinthine ossification was the detected pathology. In 1 child, the common cavity of the right ear was associated with congenital melanocytic naevus of the left eyelid and lipomeningocele. To the best of our knowledge, this condition has never been described.

CONCLUSIONS

The aetiology of UHL may be revealed in more than half of patients by means of TBHRCT. Besides common inner ear abnormalities, TBHRCT should be evaluated carefully to rule out HJB, dehiscences, diverticulum or erosion of inner ear structures.

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.

Assessment of deafmute patients: a study of ten years

Present prospective study was conducted on 350 patients presenting with chief complaints of impaired hearing and delayed speech from 1996-2006. The aim of the present study was to find out the prevalence of deafmutism in our area, the aetiology of childhood deafness and to ascertain the role of acoustic reflex test (ART) for hearing screening considering brain stem evoked response audiometry (BSERA) as gold standard. A detailed history, clinical and other relevant systemic examination and investigations were done to find out the cause. All patients were subjected to ART test and BSERA. Male to female ratio was 2.1:1. Prevalence was found to be 5.59 per one lac population in our district. The commonest age of presentation was in the second decade. The causes for childhood deafness were genetic (15.8%), embryopathies (10%), perinatal (10.8%) and postnatal problems (12.5%). In 50.6% cases it was aediopathic. Congenital syndromic abnormalities were found in 5.4% patients. In BSERA 21% patients were found to have residual hearing varying from 60 dB to 100dB. The positive predictive value of ART was found to be low (10.4%). Hence it was recommended that ART should not be used as screening tool for childhood deafness.

Comparative evaluation of Transient Evoked Oto-acoustic Emissions and Brainstem Evoked Response Audiometry as screening modality for hearing impairment in neonates

OBJECTIVE

This study was designed to evaluate Transient Evoked Oto-acoustic Emission (TEOAE) as screening modality for hearing impairment in neonates. Brainstem Evoked Response Auditometry (BERA) was used as gold standard diagnostic tool in this study. The factors affecting the specificity of TEOAE were also studied.

METHODS

The study group of 200 randomly selected neonates was subjected to TEOAE and BERA (400 ears). Oto-endoscopy was done in all TEOAE failures and a repeat test was done after suction cleaning of blocked external auditory canal (EAC).

RESULTS

Otoscopic evaluation of all 52 TEOAE failures was done. EAC obstruction was noticed in 31 ears and 4 ears showed collapsible EAC. TEOAE was repeated after suction cleaning of the obstructed EAC and using long probe tips for collapsible EAC. This improved the Pass rate of TEOAE from 87% to 92%. EAC obstruction and collapsible EAC were the two factors identified in this study that significantly affected the specificity of TEOAE as a screening test. Pass rate of TEOAE in <48 hrs age group was found to be 55.5%, which was nearly half of over-all pass rate. This was because of high prevalence of obstructed EAC in this age group. TEOAE was found to be a rapid screening tool as average time taken for BERA was 35 min/neonate and for TEOAE was 17.4 min/neonate. Acceptability of TEOAE was found to be higher as compared to BERA.

CONCLUSIONS

TEOAE is a simple and rapid test with relatively higher acceptability. But, the low sensitivity and specificity are the main shortcomings that take away from TEOAE, the status of independent screening modality for hearing impairment in neonates. TEOAE cannot completely replace BERA as screening modality for hearing impairment in neonates, however can complement it.

Initiators in processes leading to hearing loss identification in Finnish children

The objective was to examine processes leading to the diagnosis of hearing loss in children. The subjects were 328 children (hearing loss >30 dB HL) fitted with hearing aids in Helsinki University Central Hospital. The risk factor initiated hearing loss detection in 31%, whereas parental suspicion accounted for 26% and hearing screening at the well-baby clinics for 20% of the subjects. Parents were foremost to suspect hearing loss at the age spoken language normally emerges (1.5-3.4 years). Screening was equally effective irrespective of the severity of hearing loss. Parents with misgivings of hearing impairment in their child should have compliant access to audiological units.

Identification of neonatal hearing impairment: infants with hearing loss

OBJECTIVE

This article describes the audiologic findings and medical status of infants who were found to have hearing loss, detected as part of the Identification of Neonatal Hearing Impairment (INHI) project. In addition, the neonatal and maternal health variables for the group of infants who could not be tested with visual reinforcement audiometry (VRA) due to developmental and visual disability are presented.

DESIGN

The overall goal of the INHI project was to evaluate the test performance of auditory brain stem response and evoked otoacoustic emission (OAE) tests given in the newborn period. These tools were evaluated on the basis of the infants' hearing when tested behaviorally with VRA at 8 to 12 mo corrected age. The neonatal test results, VRA results, medical history information and a record of intercurrent events occurring between the neonatal period and the time of VRA were collated and reviewed. The purpose of this article is to review the characteristics of those infants who were found to have hearing loss.

RESULTS

Of 2995 infants who had VRA tests judged to be of good or fair reliability, 168 had a finding of hearing loss for at least one ear, an incidence of 5.6%. Sixty-six infants had bilateral losses, an incidence of 2%, and 22 infants had bilateral hearing losses in the moderate to profound range, an incidence 0.7%. The prevalence of middle ear problems was greater than 50% among these infants with hearing loss. From the larger group of 168 infants with hearing loss, a group of 56 infants (86 ears) was chosen as those with a low probability that the hearing loss was due to transient middle ear pathology and was more likely hearing loss of a permanent nature. These were the infants used for the analyses of neonatal test performance (Norton et al., 2000). In this selected group there were 30 infants with bilateral impairment of at least mild degree, which is an incidence of 1%. There were approximately equal numbers of ears in the mild, moderate, severe and profound range of hearing loss. Risk factors associated with hearing loss were reviewed for the total sample of infants tested with VRA and for those infants with hearing loss. A history of treatment with aminoglycosides was the risk factor most often reported in the entire sample; however, there was no difference in prevalence of this risk factor for the normal-hearing and hearing-impaired groups. The risk factor associated with the highest incidence of hearing loss was stigmata of syndromes associated with sensorineural hearing loss and other neurosensory disorders. Sixty-seven infants who returned for follow-up could not be tested with VRA due to severe developmental delay or visual disability. Many of these infants had medical histories indicating the sequelae of extreme prematurity and/or very low birthweight.

CONCLUSIONS

Most of the hearing losses found in this study were mild and, based on clinical history and tympanometry tests, many of the mild and some of the moderate impairments may have been acquired in early infancy due to middle ear effusion. In the group of infants used for determination of neonatal test performance there were approximately equal numbers of mild, moderate, severe and profound losses. Only a small percentage of infants with a conventional risk indicator for hearing loss actually had a hearing loss, and there were a significant number of infants with hearing loss who did not have a risk indicator. These findings support the need for an early identification program based on universal neonatal hearing screening rather than by targeted testing of those with risk indicators.

Survey of the pre-school child health surveillance programme in Sweden

A survey of the programme for developmental surveillance in the Child Health Centres (CHCs) in Sweden was performed using a questionnaire administered to the Chief Medical Officers (CMO) of the Child Health Services. The questionnaire asked about methods used for auditory examination, developmental surveillance and identification of disturbances in mother-child interaction. Activities for health promotion concerning breastfeeding, non-smoking and allergy prevention were also queried. Thirty-four CMOs representing 1731 CHCs and 645,000 children answered the questionnaire. The reply rate was 81%. Various methods of auditory examination are offered all infants and children in Sweden. The national guidelines for health supervision are followed fairly closely by all. Screening for disturbances in attention, motor development and perception (DAMP) is performed by all but four districts, with various methods, resources and degrees of co-operation with school health services. Support in mother-child interaction is considered very important and new methods to identify and treat disturbances are gradually introduced. Breastfeeding is encouraged; breast milk is the main source of food for 67% of babies at 4 mo of age. Activities to stop or diminish use of tobacco are ongoing everywhere, as are programmes to identify children at risk of developing allergies and for allergy prevention. Thus, the Child Health Services maintain a high standard and are ambitious about introducing new methods and ideas.

Causes of hearing impairment in deaf pupils with a mental handicap

An aetiological study was performed on 122 deaf pupils (57 aged < 20 years, 65 aged > 20 years) at the Institute for the Deaf in Sint-Michielsgestel, The Netherlands. Besides hearing impairment with thresholds of > 60 dB HL, all the participants had a mental handicap with a non-verbal IQ of 40-80. Sixteen per cent of them were of non-Dutch origin. The cause of hearing impairment was acquired in 48%, inherited in 17%, chromosomal in 4% and unknown in 30%. In comparison with other studies on the aetiology of childhood deafness, acquired causes predominated over inherited causes, which may be typical of deafness combined with a mental handicap. We found a significant predominance of non-Dutch pupils among the rubella aetiology cases and male predominance among the hearing impaired pupils in general.

Autism and hearing loss

A group of 199 children and adolescents (153 boys, 46 girls) with autistic disorder was audiologically evaluated. Mild to moderate hearing loss was diagnosed in 7.9% and unilateral hearing loss in 1.6% of those who could be tested appropriately. Pronounced to profound bilateral hearing loss or deafness was diagnosed in 3.5% of all cases, representing a prevalence considerably above that in the general population and comparable to the prevalence found in populations with mental retardation. Hearing deficits in autism occurred at similar rates at all levels of intellectual functioning, so it does not appear that the covariation with intellectual impairment per se can account for all of the variance of hearing deficit in autism. Hyperacusis was common, affecting 18.0% of the autism group and 0% in an age-matched nonautism comparison group. In addition, the rate of serous otitis media (23.5%) and related conductive hearing loss (18.3%) appeared to be increased in autistic disorder. The study emphasizes the need for auditory evaluation of individuals with autism in order to refer those with pronounced to profound hearing loss for aural habilitation and to follow those with mild to moderate hearing loss because of the risk of deterioration.

Prevalence and etiology of unilateral sensorineural hearing impairment in a Finnish childhood population

A retrospective study was undertaken on the prevalence and etiology of unilateral sensorineural hearing impairment (> 25 dB at 0.5-4 kHz, including mixed hearing impairments with bone conduction thresholds > or = 25 dB) among children born between 1972 and 1986 in a province of eastern Finland. Only patients who had been diagnosed before the age of 10 years were included. A total of 84 children with such an unilateral hearing loss were identified, with prevalence of 1.7 per 1000 live births. A significant decline from the prevalence of 2.2 per 1000 in the 1970s to the prevalence of 1.2 per 1000 in the 1980s was observed, which was mainly due to the disappearance of hearing losses caused by mumps and measles in the 1980s and the decrease in cases attributed to otitis media. In agreement with some previous studies, a considerable male predominance was present. Thirty-five percent of the hearing losses were profound (> 95 dB) and 15% were severe (71-95 dB). Etiology of the hearing impairment was estimated as genetic in 2%, congenital non-genetic in 12%, delayed-onset non-genetic in 35% and remained unknown in 51%.

Prevalence and etiology of bilateral sensorineural hearing impairment in a Finnish childhood population

A retrospective study was performed on the prevalence and etiology of bilateral sensorineural hearing impairment (> 25 dB at 0.5-4 kHz in the better ear) among children born 1974-1987 in a province of eastern Finland. A total of 98 children with hearing impairment were identified, which gave a prevalence of 2.1 per 1000 live births. This prevalence was higher than reported form most of other developed countries but slightly lower than reported from Sweden. A slight decline from the prevalence of 2.3 per 1000 in the 1970s to the prevalence of 1.9 per 1000 in the 1980s was observed. Contrary to several earlier studies, no male predominance was noted, there were even slightly more females than males (52 vs. 46). Etiology of the hearing loss was estimated to be genetic in 41%, congenital nongenetic in 13%, delayed-onset nongenetic in 16% and remained unknown in 30%. On average, children with a congenital disorder had more severe hearing impairment than those with delayed-onset hearing loss, e.g. 31% of the former patients had profound (> 95 dB) hearing loss compared to 6% of the latter. A very gratifying finding was that no case of congenital hearing impairment caused by maternal rubella was identified after 1982, obviously due to general vaccinations. Also, a decline in cases of hearing loss attributed to perinatal and neonatal complications was observed.

Early identification of children with communication disabilities--evaluation of a screening programme in a Swedish county

OBJECTIVE

The aim was to evaluate the effectiveness of an early screening programme for communicative disturbances in relation to the health status of the child at the age of 4 years.

MATERIALS AND METHODS

A case-control study including 705 cases and 2451 controls was performed.

RESULTS

Cases with communication disorders as well as other types of disabilities at 4 years of age showed a higher frequency of deviant screening results on each screening occasion. The sensitivity for the screening programme amounted to 24.8%, the specificity was 95.5% and the positive predictive value was 61.2%.

Click-evoked oto-acoustic emissions in very-low-birth-weight infants: a cross-sectional data analysis

For the purposes of studying the phenomenon of evoked oto-acoustic emissions (EOAEs) in very-low-birth-weight (VLBW) infants, and the conditions affecting the utility of EOAE ear screening in this population, click EOAEs were repeatedly recorded in ears of 144 VLBW infants, at different postconceptional ages of the infants and at two different test sites, i.e. in the neonatal high-care unit (ward), or at the neonatal outpatient clinic. The postconceptional age of the infants examined in the ward was 30-49 weeks and 37-66 weeks for the infants examined at the outpatient clinic. Overall 840 recording attempts were done. In the ward 86% of these attempts (388) were successful against 60% (of 452 attempts) at the outpatient clinic. In the latter group of infants the success rate of recording was only 33% at the corrected age of 6 months, which is significantly less than the 66% until the corrected age of 3 months. For a cross-sectional analysis of age effects one ear of each successfully recorded infant was selected. Analysis of the 127 successful recordings revealed that the EOAE prevalence was 71% in the ward (54% for infants receiving extra oxygen per naso) and 91% at the outpatient clinic. Compared with healthy newborns, VLBW infants are much more difficult to test, especially at the outpatient clinic. However, the EOAE prevalence at this test site is the highest and approaches that in healthy newborns. At the outpatient clinic response levels of EOAEs recorded approach levels found in healthy newborns. The higher success rate of recording in the ward and the lower EOAE prevalence are two counteracting factors as to the utility of EOAE-based ear screening of VLBW infants.

Congenital cytomegalovirus infection and neonatal auditory screening

Auditory screening of newborn infants has been recommended on the basis of the presence of risk criteria, including congenital infection. We assessed the ability of risk criteria-based neonatal auditory brain stem response to identify infants with hearing loss resulting from congenital cytomegalovirus (CMV) infection. Data from 6 1/2 years of risk criteria-based neonatal auditory screening were compared with the results of screening of all newborn infants for congenital CMV infection. Infants with congenital CMV infection received follow-up hearing evaluations. Congenital CMV infection was found in 167 (1.3%) of 12,371 infants; 134 had follow-up hearing evaluations, and 14 (10.4%) had confirmed sensorineural hearing loss. The rate of sensorineural hearing loss resulting from congenital CMV infection was 14 per 12,371 infants, of 1.1 per 1000 live births; the rate of bilateral loss > or = 50 dB was 0.6 per 1000. Although 2036 infants received auditory screening because of risk criteria, only 34 (20%) of 167 infants with congenital CMV infection were included. Only 2 (14%) of 14 children with sensorineural hearing loss caused by CMV were identified by risk criteria-based screening. We conclude that congenital CMV infection is an important cause of hearing impairment. Neonatal auditory screening based on the presence of risk criteria will fail to identify the majority of cases of sensorineural hearing loss caused by congenital CMV infection.

Click-evoked oto-acoustic emissions in 1036 ears of healthy newborns

Click-evoked oto-acoustic emissions (EOAEs) were recorded in 1036 ears of healthy newborns and in 71 normal-hearing adult ears. Newborns aged between 3 and 238 h were examined in a separate but not silent room of the obstetric ward. The adults were tested in a quiet but not sound-treated room. The recordings were more difficult in the newborn than in the adult, which was mirrored in recording parameters such as the time required for measurement (up to 7 min in newborns vs. 1-2 min in adult ears). Recording was always successful in adults, while retests were necessary in 4% of newborns. Also the artefact-rejection level and the stimulus stability were more favourable in adults. Still, EOAE recording for screening purposes in newborns seems feasible. Response levels in newborns (range 1.6-38.6; mean 20.2 dB SPL) appear to be higher than in adults (range 2.7-20.6; mean 12.8 dB SPL). The overall prevalence of EOAEs in newborns amounted to 93.4% and appeared to be age related. It rises from 78% in ears from newborns younger than 36 h to 99% in ears of newborns older than 108 h. This rise may be related to the middle ear clearance of amniotic fluid in the first days post partum. The prevalence in newborns older than 3-4 days is comparable with the prevalence of 97.2% in adults. Therefore, newborns should not be screened before the age of 4 days. In search of an objective EOAE detection variable, the prevalence of EOAEs for different age groups was calculated for various criterion values of reproducibility. These prevalences were compared to subjectively scored EOAE prevalences in the same age groups. A reproducibility criterion of about 50% appears to be useful for mass screening in newborns.

On criteria for hearing impairment in children

As objective criteria concerning hearing impairment/disability may be poorly related to the behavioral patterns of children with hearing deficits, the present investigation was performed. A consecutive series of 172 children, who were examined for the first time at the Audiological Department, was subdivided according to age into two groups: one comprising 98 children at an age from 49 to 84 months, the other comprising 74 children greater than 84 months of age. This second group is supposed to complain of hearing problems if present, and thus constitutes a reference group. Using the criterion for hearing impairment: BEHL 0.5-4 kHz greater than 20 dB HL, the data demonstrated that the frequency of correct and false positive suspicion (detection) of a hearing impairment is similar in parents and professionals with an observer sensitivity of 88%. In addition the frequency of suspicion in parents and professionals in relation to degree of hearing loss corresponds to the frequency of hearing problems, as experienced in the reference group of older children. A certain discrepancy exists between the applied criterion of BEHL 0.5-4 kHz greater than 20 dB and the hearing level resulting in deviating behavioral pattern or experienced hearing deficit in children. This may be ascribed to the predominantly conductive hearing loss in the examined sample. It is concluded that additional investigations on criteria for hearing impairment/disability, including also children with sensorineural hearing loss should be undertaken.

Children younger than 4 years of age, referred to an audiological department

This investigation was performed in order to evaluate why and by whom children less than or equal to 4 years of age were referred to the regional audiological department in Copenhagen: and in addition to describe the audiological investigation and the obtained results in relation to the relevance of the referral. One hundred and forty consecutive first time referred children, 92 males and 48 females, at a median age of 28 months, range 2-49, were included. Of them 71.4% were referred from the general practitioners or local ENT doctors, while only 9.3% were examined on the parents' self-request. The parents were the first to raise suspicion of a hearing loss in 60%, which differs significantly from the 32% correctly found in professionals. The rate of false positive suspicion was similar in the two groups. Forty-nine % of the referred children suffered from hearing impairment, predominantly due to otitis media with effusion. Only 9% of the children were able to perform a pure-tone audiogram. A frequency of 2.9% of children with congenital/early acquired hearing loss was found and a delayed identification demonstrated. The investigation shows that the parents are more efficient in their observation of children concerning hearing loss than professionals, and that the prevalence of "true audiological children" is so restricted that the pediatric audiological services should be centralized and form part of the health hearing service offered to the hearing-impaired. In addition was found that the special equipment and expertise needed for audiological evaluation in young children is used fairly relevantly.

Nonsyndromal profound genetic deafness in childhood

About one-half of children with profound deafness have an autosomal recessive or autosomal dominant inherited type of deafness. The X-linked inherited types of deafness are rare. About one out of three profoundly deaf children has an autosomal recessive form of inherited deafness. At sometime during their life a syndromal diagnosis can be made in one out of four cases with an autosomal recessive form of deafness. Therefore in about 25% of all the children with profound deafness, a nonsyndromal autosomal recessive type of genetic deafness will be involved. It is still not clear how many different genes are responsible for this. The more severe the deafness in a child, the greater the chance that an autosomal recessive etiology is involved. The autosomal dominant inherited types of deafness are significantly more frequent in cases where the hearing loss in the best ear is less than 80-90 db. About one-half of the autosomal dominant inherited cases show a classical syndromal type of deafness based on clinical features. In the other half, some audiometrically recognizable types of deafness can be diagnosed after an autosomal dominant pattern of inheritance has been established. Additional genetic knowledge based on gene-linkage studies is needed to provide better tools for the more accurate diagnosis of genetic etiology in a profoundly deaf child. Adequate pedigrees are quite rare and such pedigrees are expected to become even more scarce as a result of a diminishing ratio of consanguineous marriages. It is necessary to start gene-linkage studies in these existing pedigrees to trace the genes responsible for this nonsyndromal type of profound genetic deafness in childhood.

An analysis of the aetiology of early childhood deafness

It is generally believed that one in every thousand children is profoundly deaf. An understanding of the aetiology of early childhood deafness and timely detection is crucial in rehabilitation of these children. This study analyses the aetiology of early childhood deafness and shows that deafness is more often acquired than inherited. Non-syndromic deafness, especially occurring on its own, usually produces profoundly deaf children and thus there is the need for genetic studies--in the child, laterally, and longitudinally into generations. Meningitis appears to be the commonest cause of acquired deafness, especially if due to pneumococcus. Only 40 of the 80 cases presented before the age of 2 years. It was therefore interesting to note what factors invoked awareness of deafness to facilitate early presentation.

Review of a high risk register for congenital or early-onset deafness

This paper is an attempt to assess the success of a high risk register for congenital or early onset of severe to profound hearing impairment. With some years experience, and a large number of publications, it is possible to evaluate (at least in part) the extent to which such a register actually does permit us to identify these infants. To that end, an extensive review is reported here and some recommendations are made.

Screening for sensorineural deafness by health visitors. The Steering Committee, Oxford Region Child Development Project

Screening for hearing loss in the first year of life, using the distraction test, remains the responsibility of health visitors in most health districts in the United Kingdom. We have evaluated the screening procedure used routinely in one health region in a population of infants at increased risk of sensorineural deafness. They were infants who weighed less than 2000 g at birth or infants who weighed 2000 g or more at birth and who spent more than 24 hours in a special care nursery. The infants' responses to a distraction test were recorded by health visitors and sent to the project office. The results were compared with information from a regional register of early childhood impairment that included children in whom sensorineural deafness had been diagnosed before the age of 3 years. The register had been compiled using information from a wide range of sources. When used in this high risk population the distraction test was sensitive (91%), but nonspecific (82%). The effectiveness of the screening programme was limited, however, because there was an increased risk of deafness among infants who missed being screened by health visitors. In addition, 71% of the deaf infants on the register were not in the high risk population.

Hearing identification in difficult-to-test children. A study of 142 infants and children

Prior to auditory brainstem response (ABR) threshold determinations in 142 anaesthetized 'difficult-to-test' children, 125 had one or more behavioural auditory tests performed. We used the ABR thresholds as a basis and retrospectively analysed the case records in relation to some parental and behavioural auditory aspects. The accuracy of the parental opinion regarding hearing has been evaluated, and showed a relatively high rate of false-negatives (29%). In contrast, the presence of a hearing loss was correctly identified in 53%. The reliability of one or more standard behavioural auditory tests was poor in children with normal hearing, but in hearing impaired, there was agreement between ABR and behavioural results in more than 70% of cases. Median age at the ABR examination was 32 months. These and other results are discussed in view of the need to minimize diagnostic delay.

Hearing impairment in connection with preauricular tags

Between 1977 and 1984, 230 newborns (5.4/1,000 livebirths) were registered at the two maternity hospitals of Göteborg as having preauricular tags. Of these 188 were available for hearing assessment. In 10 children (5%) the tag was associated with other malformations of the ear/face region. All these children had hearing impairment (HI), 8 conductive, 1 sensorineural and 1 mixed. In 178 neonates the tag was the only defect. Of these, 23 (13%) were found to have HI, all sensorineural and of mild to moderate degree. In the total group of children a positive family history for HI was found in 29% and for malformation in 24%. In the children where HI was found (33 cases in total) the figures for heredity rose to 67% (HI) and 30% (malformation). In the 23 cases with ear tag and HI, a hereditary tendency for HI was found to be 78%. Accordingly there is a clearly elevated risk for HI in connection with ear tags and we therefore recommend routine hearing assessment in all children with preauricular tags.

Perinatal risk factors in the aetiology of hearing loss in preschool children

In order to assess the importance of pertinent perinatal risk factors in causing hearing loss (HI), a retrospective evaluation was made of the records of 146 affected children born in the city of Göteborg between 1970 and 1979. The incidence among six-year-olds born between 1970 and 1974 was 3.8 per 1000 newborns. If only HI of more severe degree was taken into account (above 40dB in the best ear), the remaining incidence was 1.4/1000. Sensorineural HI (SNHI) accounted for 87 per cent of the cases. A positive hereditary tendency for HI was found in 55 per cent. In 61 per cent the origin of the HI was presumably prenatal, either positive heredity alone or in the form of facio-auricular anomalies, syndromes and toxic influences (infection and alcohol) during early pregnancy. Postnatal infections (meningitis, parotitis and secretory otitis media) could be ascertained as causes in about 20 per cent of the cases. For 12 per cent no aetiology could be determined. Perinatal aetiology was probable or possible in about 10 per cent of the children. The frequency of SNHI was found to be increased among survivors of neonatal intensive care, VLBW, LBW and SFD infants. Caesarean section, ventouse and breech delivery were not associated with increased rates, nor were hyperbilirubinaemia, exchange transfusion or birth asphyxia. No cases could be traced to aminoglycoside treatment. Neonatal sepsis/meningitis may have been the cause in two of the 146 cases. Hypoxia as a consequence of apnoea and respiratory distress syndrome necessitating mechanical ventilation appeared to be the major risk-factor in the neonatal period. However, in comparison with genetic predisposition, potentially damaging perinatal factors appeared to be of minor importance.