Aetiology Of Hearing Impairment Research Articles

Hearing problems at working age: Audiometric features and the aetiology of hearing impairment

Sixty patients, 37 women and 23 men, aged 30−65 years, were included in the study. All had adult-onset hearing loss to an extent that necessitated hearing-aid fitting. The objective was to describe the audiometric features and extent of hearing loss, and to determine the aetiology of hearing impairments in hard-of-hearing patients in working life. The extent of hearing loss varied considerably; about one-third of the patients had moderate to severe hearing loss in both ears, about one-third had bilateral, mild hearing loss, and somewhat less than one-third had unilateral or asymmetrical hearing loss, with mild loss or even normal hearing in one ear. In 77% of the cases a diagnosis, verified or tentative, could be established. Middle ear disease with conductive or mixed hearing loss was found in 20% of the cases. Noise-induced hearing loss was diagnosed in 10% of the cases. The most common, but highly tentative, diagnosis was hereditary hearing loss. Including cases of otosclerosis, genetic hearing loss wa...

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 > 20dB 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 8000Hz, for the average of 500, 1000, 2000 and 4000Hz, for the average of 2000 and 4000Hz and for the average of 4000 and 8000Hz. Those showing a progression >15dB for the average across 500–4000Hz 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.

Epidemiology of permanent childhood hearing loss in Glasgow, 1985-1994.

This retrospective study was undertaken to document the epidemiology of permanent childhood hearing impairment (PCHI) in Glasgow and to make some assessment of the current practice to identify these children before universal neonatal hearing screening (UNHS) is implemented. Subjects were those with bilateral permanent hearing impairments of at least 40 dB in the better hearing ear, born between 1985 and 1994, in Greater Glasgow. The subjects were identified and data extracted from the Educational Audiology database. The case records at the Royal Hospital for Sick Children were also reviewed to identify possible aetiology groups. The prevalence rate of all permanent hearing impairments was 1.23 per thousand live births. Eleven percent of all hearing impairments were acquired or progressive. There was no significant effect of sex on aetiology (X2 = 6.509, df = 6, p, = 1), age at identification of hearing impairment and hearing aid provision (Kruskal Wallis, p = 0.484 and 0.782 respectively). For those identified as congenitally hearing impaired, the median ages at diagnosis of hearing impairment and hearing aid provision were 18 months and 31 months respectively. Age at diagnosis of hearing impairment and hearing aid provision were unaffected by aetiology of hearing impairment (Kruskal Wallis, p = 0.782 and p = 0.484 respectively). The prevalence rate of PCHI and the ages at identification and intervention in Glasgow are typical of the rest of the UK. Audiological surveillance measures are falling well below the standard of care expected today and the introduction of UNHS is likely to improve outcomes as long as the additional health and educational resources are in place to deal with the earlier identification of these children.

Changes in the aetiology of hearing impairment in deaf–blind pupils and deaf infant pupils at an institute for the deaf

An aetiological study was performed on 57 pupils at the deaf–blind department of the Institute for the Deaf at Sint-Michielsgestel, The Netherlands, in the school year 1998–1999 and on 49 deaf–blind pupils at the same department in the school year 1986–1987. The pupils were 5–20 years of age. In addition, the aetiologies were studied in 55 deaf infant pupils in 1998 and compared with those of 68 deaf infant pupils in 1988. Their age was 1–5 years. All the pupils showed hearing impairment with thresholds of >60 dB HL. Among the deaf–blind pupils and deaf infant pupils, there were several cases with rare hereditary syndromes. The prevalence of acquired causes of deafness, especially congenital rubella, had decreased over the years, whereas perinatal causes of deafness had increased. Chromosomal anomalies were found in 15% of the infant pupils in 1998. Over the study period, the percentage of pupils with multiple handicaps increased from 25 to 38%.

Hearing impairment among ‘at risk’ children

A survey was carried out to identify the prevalence and the aetiology of hearing impairment among infants and children at risk based on the criteria. Out of 6421 surveyed children, 1256 (19.6%) were found ‘at risk’ for hearing impairment. Children with hearing impairment in this study were found to be 494 which represent 39.3% of the ‘at risk’ children. We found 326 (66%) children had conductive hearing loss almost all associated with secretory otitis media ( n = 232). Sensorineural hearing loss affected 168 (34%) children. Heredo-familial causes were responsible for about 111 (66.1%) cases. The detailed causes of conductive and sensorineural hearing loss are presented and compared with other studies in the literature. Conductive hearing impairment was mild in the majority of the cases n = 271, (83%), moderate in 55 (17%) cases. Sensorineural hearing loss was mild in 113 (67.3%), moderate in 32 (19%) and profound in 23 (13.7%) cases. A large scale Kingdom-wide study to focus on aetiology of deafness among Saudi infants and children to find out the extent of this problem is recommended.

Epidemiology of hearing loss and aetiological diagnosis of hearing impairment in childhood.

A total of 117 children, 55 girls and 62 boys with a median age of 8 years, range 2-12 years, was retrospectively evaluated in consideration of: (1) the prevalence rate and characteristics of permanent hearing loss (defined as the average of 500, 1000 and 2000 Hz greater than or equal to 35 dB HL on the better hearing ear); (2) the aetiology of the hearing impairment; (3) the basis for the aetiological diagnosis in the individual child, and (4) the value of non-audiological investigations. The overall prevalence of permanent hearing loss was 1.4% in this geographical area (children with recurrent episodes of serous otitis media are excluded). In 91% (106/117) the hearing loss was sensorineural, in 4% (5/117) conductive and in 5% (6/117) mixed conductive/sensorineural. In 63% (74/117) the hearing loss had been confirmed and assessed at the age of 3 years, while in 31% (37/117) the hearing loss was ascertained after the age of 3 years. 85% (99/117) were considered to suffer from congenital/early acquired hearing loss. The aetiology of hearing impairment could be assessed in 73% (85/117) of the children, while 27% (32/117) were diagnosed as 'unknown aetiology'. In 48% (56/117) combined audiological/non-audiological investigations had been performed, resulting in a known aetiology in 86% (48/56). In 52% (61/117) only audiological examination had been performed, resulting in a known aetiology of 61% (37/61). A significant difference (P less than 0.005) in known aetiology between these two groups is present, indicating that additional non-audiological evaluation is of decisive importance in the aetiological assessment of hearing impairment. Based on the present and previous investigations, a routine examination programme is proposed directed towards a systematic evaluation of the symptom of hearing loss and its aetiology with due caution to the individual child. The evaluation should be based on a combination of audiological/non-audiological examinations, which includes a broad interdisciplinary cooperation that preferably should be performed at diagnostic assessment centers.

Hearing impairment in meningococcal meningitis.

Hearing affection as a sequel of meningococcal meningitis and its relation to age, sex, severity and duration of disease was studied in Cairo, Egypt during the period December 1966--December 1973. The total incidence of impaired hearing in the 775 cases was 5.8%. This incidence was higher in the younger age groups, females, severe cases of meningitis and in patients who received specific therapy shortly after the onset of signs and symptoms of the disease. The aetiology of hearing impairment in meningitis was reviewed.

Hardness of Hearing in School Children: A Study of Schooling and the Aetiology of Hearing Impairment Among the Pupils of a Danish Hearing School Now and 10 Years Ago

For educational purposes deaf children in Denmark are divided into two main groups on the basis of the degree of hearing loss, speech, and intelligence. These two main groups are educated separately.