Epidemiology of permanent hearing impairment in children in relation to costs of a hearing health surveillance program

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.

Congenital and compensated vestibular dysfunction in childhood: an overlooked entity

We report five children with previously unrecognized vestibular dysfunction detected by clinical examination and confirmed by quantitative vestibular testing. Patient 1 presented with fluctuating visual acuity and intermittent nystagmus. Patient 2 had congenital hearing loss associated with imbalance, delayed motor development, and cyclic vomiting. Patient 3 had neurotrophic keratitis with an intermittent head tilt, imbalance, and motor delays. Patient 4 showed ataxia and eye movement abnormalities following traumatic brain injury and had reading difficulties. Patient 5 had episodic vertigo and eye movement abnormalities from infancy. Clinical vestibular testing emphasized spontaneous nystagmus, rapid head thrust, and assessment of post-rotatory nystagmus. Quantitative vestibular testing included the sinusoidal chair rotation and velocity step tests, measurement of dynamic visual acuity, post-head-shake nystagmus, and computerized platform posturography. Pediatric neurologists encounter children with congenital and compensated vestibular dysfunction, which can be recognized on the basis of relevant history and clinical abnormalities of the ocular-ocular reflex.

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.

Longitudinal study of hearing impairment in children

The aim of this study is to evaluate the frequency of progression in permanent childhood hearing impairment (PHI) and to relate potential specific factors to the eventual progression. A description is made of the true longitudinal hearing thresholds in four groups of children according to different observation periods and being part of a prospective pediatric audiological registry-based study established in 1989. At the time of data collection the registry included 1373 children born after 1/1-1970 with a PHI > 20 dB in either the right or the left ear at any pure tone frequency. The children were subdivided according to the following observation periods: 1-3 years (N=266), >3-5 years (N=148), >5-10 years (N=212) and >10 years (N=62). The differences from the first to the most recent audiometric thresholds were analysed for the right and left ears separately, at the pure tone frequencies 250, 500, 1000, 2000, 4000 and 8000 Hz, for the average of 500, 1000, 2000 and 4000 Hz, for the average of 2000 and 4000 Hz and for the average of 4000 and 8000 Hz. Those showing a progression >15 dB for the average across 500-4000 Hz were analysed for age at onset and aetiology of hearing impairment, showing that genetic factors are predominant in progressive PHI. It was also found that progression in PHI is most frequent in early childhood but found only in 5.7% after the age of 4 years.

Evaluation of vestibular function in young children

Together, these tests provide a full evaluation of vestibular function in infants and small children. If attention is paid to creating the appropriate testing environment, and interpretation of the tests takes into account the unique properties of the responses of infants and young children, this testing can provide a useful adjunct to audiometric evaluation in young children.

The need for universal neonatal hearing screening--some aspects of epidemiology and identification

The devastating consequences of a congenital/early-acquired hearing disability on the speech language and social development of a child and the estimated prevalence rates of at least 1-1.5/1000 live births of congenital permanent hearing impairment are important health problems. Universal neonatal hearing screening programs have provided the opportunity to detect neonates with permanent congenital hearing loss, and thus initiate auditory rehabilitation before the age of 3 mo. Universal neonatal hearing screening represents secondary prevention of hearing impairment/deafness, and the world-wide documented delayed identification of children with congenital/early-acquired hearing impairment will no doubt be improved with the implementation of universal neonatal hearing screening programs.

Hearing screening--aspects of epidemiology and identification of hearing impaired children

Mass screening of hearing in children is based on the concept of secondary prevention. In recognition of the importance of an early identification and intervention in children with congenital or early-acquired (i.e. neonatal period) hearing disability, numerous hearing screening programs have been introduced throughout the world. The devastating consequences of a congenital/early acquired hearing disability upon the speech, language, and social development of a child, and the estimated prevalence rates of at least 1-1.5/1000 live births of congenital permanent hearing impairment, represent an important health problem. The increase in the estimated prevalence of permanent hearing impairment in childhood, reaching at least 3.6-8.2% of live births at 5-9 years of age further emphasizes the importance of the problem. The delayed identification of children with congenital/early acquired hearing disability should result in the implementation of universal neonatal hearing screening, and the negative impact on the learning processes during school age from hearing impairment acquired throughout childhood seems to justify the introduction or maintenance of a hearing screening at school entrance. Implementation of efficient hearing screening programs throughout the neonatal period, infancy, or childhood should result in secondary prevention of this important health problem.