In the present study, pure-tone audiometry was used in 687 Finnish school children, aged 6-15 years, to determine the prevalence of a 6 kHz acoustic dip and related factors among three age groups. Trained audiometricians tested air conduction thresholds in a sound-proof room. A total of 57 children (8.3%) had a clear-cut dip of at least 20 dB at 6 kHz. This dip was more pronounced in older children and in boys. A thorough case history was obtained by questionnaire, with logistic regression analysis showing that low birth weight (
The A1555G mutation of the mtDNA is associated with both aminoglycoside-induced and non-syndromic hearing loss. The A1555G is relatively frequent in the Spanish and some Asian populations, but has only been reported rarely in other populations, possibly because of ascertainment bias. We studied 85 Danish patients with varying degrees of hearing impairment and found two patients with the A1555G mutation (2.4%). Neither had received aminoglycosides. Our study indicates that the mutation might not be uncommon in Danish patients with hearing impairment.
It is suggested that, within the same energy level, an impulse noise is more hazardous to hearing than a permanent noise. To justify this hypothesis, a study was performed with groups of wood-cutters and shipyard workers to investigate different characteristics of noise load (noise levels, noise impulsivity from the outside and under the ear-flaps, noise emission levels with regard to the length of work and using ear-flaps), and hearing losses (both real and forecasted on the Robinson model). To avoid individual factors, a computerized assessment of 38 pairs of workers from both teams was performed (with regard to similar noise emission levels, diastolic pressures, smoking habits, their military service backgrounds as to the service in heavy artillery units, absence of otic diseases, low consumption of salicylates). The results showed that, within the same energy level, the noise in the shipyard was three times as impulsive and more otic disorders inducing than the noise in the wood-cutters' working conditions.
The objective of this study was to evaluate the influence of atherogenic risk factors on hearing thresholds. In a cross-sectional study we analyzed data from a Danish survey in 2009-2010 on physical and psychological working conditions. The study included 576 white- and blue-collar workers from children's day care units, financial services and 10 manufacturing trades. Associations between atherogenic risk factors (blood lipids, glycosylated hemoglobin, smoking habits, body mass index (BMI), and ambulatory blood pressure) and hearing thresholds were analyzed using multiple linear regression models. Adjusted results suggested associations between smoking, high BMI and triglyceride level and low high-density lipoprotein level and increased low-frequency hearing thresholds (average of pure-tone hearing thresholds at 0.25, 0.5 and 1 kHz). Furthermore, an increasing load of atherogenic risk factors seemed associated with increased low-frequency hearing thresholds, but only at a borderline level of statistical significance. Associations were generally strongest with hearing levels of the worst hearing ear. We found no statistically significant associations between atherogenic risk factors and high-frequency hearing thresholds (average of pure-tone hearing thresholds at 4, 6 and 8 kHz).
We aimed to describe a large cohort of patients with tinnitus and sensorineural hearing loss (SNHL) in Sweden, and also to explore the possibility of finding potential possible differences between various diagnoses within SNHL. It is also of great interest to see how a multidisciplinary team was used in the different subgroups and the frequency of hearing aids use in patients with tinnitus.
Medical records of all patients who had received the diagnosis SNHL in Östergötland County, Sweden between 2004 and 2007 were reviewed. Patients between 20 and 80 years with tinnitus and a pure tone average (PTA) lower than 70dB HL were included in the study. Patients were excluded from the analyses if they had a cochlear implantation, middle ear disorders or had a hearing loss since birth or childhood. The investigators completed a form for each included patient, covering background facts, and audiograms taken at the yearly check up.
Of a total 1672 patients' medical record review, 714 patients were included. The majority of patients (79%) were in the age group over 50 years. In male patients with bilateral tinnitus, the PTA for the left ear was significantly higher than for the right ear. The results regarding the configuration of hearing loss revealed that 555 patients (78%) had symmetric and 159 (22%) asymmetric hearing loss. Retrocochlear examinations were done in 372 patients and MRI was the most common examination. In all patients, 400 had no hearing aids and out of those 220 had unilateral tinnitus and 180 patients had bilateral tinnitus. 219 patients had a PTA>20dB HL and did not have any hearing aid. Results demonstrated that the Stepped Care model was not used widely in the daily practice. In our study, patients with bilateral-, unilateral hearing loss or Mb Ménière were the most common patients included in the Stepped Care model.
In a large cohort of patients with SNHL and tinnitus, despite their hearing loss only 39% had hearing aids. It was observed that the medical record review often showed a lack of information about many background factors, such as; patients' general health condition, which could be a quality factor that needs improvement. Our results show that the Stepped Care model could be an effective option for providing a better access for tinnitus-focused treatment, although the number of patients in this study who were included in the Stepped Care model was low.
The aim of the study was to elucidate the causes of hereditary non-syndromic loss of hearing, a frequent monogene pathology in the Republic of Sakha (Yakutia). A search for mutations in the coding sequence of the connexin 26 gene gap-junction B2 (GJB2) was undertaken in 79 members of 65 unrelated families with the diagnosis of grade III-IV non-syndromic bilateral sensorineural loss of hearing. Five recessive mutations (35delG, V371, 312-326del14, 333-334delAA, R127H) and three polymorphic variants (V271, M34T, E114G) were identified in Yakut patients. Mutations 35delG (41.7%), 312-326dell4 (4.2%), and 333-334delAA (4.2%) were found in Caucasian patients (Russians, Ukrainians, Inguish). Yakuts were carriers of mutations 35delG (2.1%), V371 (2.1%), R127H (1.0%) and sequence variants V271 (6.3%), M34T (1.0%), E114G (1.0%). GJB2 mutations were identified in 50.1% of the Caucasian patients and in 7.2% of the Yakut patients. The low frequency of GJB2 mutations in Yakuts with non-syndromic sensorineural loss of hearing testifies to the presence of mutations of other genes controlling sound perception in this population.
Early intervention through hearing aids (HAs) and cochlear implants (CIs) aims to reduce the negative effects of childhood hearing loss and to promote optimal communication development over time. The primary goal of this study was to examine the communication outcomes of children with CIs and children with HAs at age 4 to 5 yrs and to consider their spoken language skills relative to a group of typically developing hearing peers.
In this multicenter observational study, communication results were obtained for a total of 88 children at age 4 to 5 yrs. Participants were recruited from three clinical programs in two cities in the province of Ontario, Canada. This study was undertaken shortly after the introduction of a new provincial population screening initiative and included both children who were screened and not screened for hearing loss. The study sample comprised 51 children with sensorineural hearing loss and 37 children with normal hearing. Of the 51 children with hearing loss, 26 used CIs and 25 used HAs. The degree of hearing loss ranged from mild to profound. All children were enrolled in rehabilitation programs focused on oral language development. Children's language skills were assessed with an extensive battery of child- and parent-administered speech and language measures.
Assessment of language skills showed no significant differences between the children with severe to profound hearing loss using CIs and children with varying degrees of hearing loss using HAs. However, children with HAs showed better articulation skills. Overall, both groups of children obtained scores on communication measures that were lower than their hearing peers. The number of children with hearing loss who obtained spoken speech-language scores within 1 SD of normative populations ranged from 65 to 86% depending on the test measure. Children with average hearing loss of 70 dB HL or better generally obtained scores on all measures in line with those of age-matched norms while scores were quite variable for children with severe and profound hearing loss. Factors influencing performance in children with hearing loss included degree of hearing loss (pure-tone average) and parent education. Age at diagnosis of hearing loss was not a significant predictor of speech-language outcomes in this study.
Results indicated that overall, children with all degrees of hearing loss who were fit with hearing technology and who received auditory-based rehabilitation services during the preschool years demonstrated the potential to develop spoken language communication skills. As a group, children with CIs and children with HAs did not differ significantly on language abilities although there were differences in articulation skills. Their performance at age 4 to 5 yrs was delayed compared with a group of hearing peers. The findings reinforce the need for research to identify factors that are likely to lead to age-appropriate communication skills for preschool-age children with hearing loss.
In an attempt to clarify international epidemiologic trends, a review of the published literature pertaining to childhood hearing loss is presented. Inconsistencies of methodology and classification, which complicate the interpretation of data and make difficult the quantification of the influence of genuine population differences, are discussed. Selective review of the literature allows certain crude statements to be made regarding childhood hearing loss. In developed countries, serous otitis media is the most common cause of hearing loss in children, affecting up to two thirds of preschool children. In addition, 1.0-2.0/1000 children have bilateral SNHL of at least 50 dB. In underdeveloped countries, suppurative middle ear disease is common and is still frequently associated with either an intratemporal or intracranial complication. SNHL appears to occur almost twice as often as in developed countries, with a greater proportion being of infectious etiology. In specific populations, the Inuits, Amerindians and Aboriginals, acute and chronic suppurative otitis media are almost endemic, yet both cholesteatoma and serous otitis media are uncommon.
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.
To determine the relationship between ethnicity and mutations in the GJB2 and GJB6 genes in multi-cultural patients enrolled in a Canadian paediatric Cochlear Implant Program.
Blood was analyzed from 65 paediatric cochlear implant users by direct sequencing of the coding region and intron/exon boundaries of the GBJ2 gene. Individuals heterozygous for one mutation in GJB2 or in whom mutations in GJB2 were not detected were analyzed for the common 342 kb deletion mutation D13S1830 in the GJB6 gene. Information regarding ethnicity of patients' families was obtained from patient records and/or interview.
GJB2 mutations were found in 36.9% of paediatric cochlear implant users tested. Nine different GJB2 mutations were identified among individuals from 14 different countries of origin. Seventy-eight percent of all identified pathogenic GJB2 mutations were 35delG. Biallelic GJB2 mutations were found in 16 cochlear implant users (66.7% of GJB2 mutations). Three novel GJB2 sequence changes were identified: (1) a missense mutation T107C (L36P) in an individual of African decent; (2) a missense mutation G475T (D159Y) in an individual of Caribbean decent; (3) a regulatory region change 1-34C to T in an individual of African decent. GJB6-D13S1830 mutations were not found in any of the patients tested. Individuals of African, Caribbean and East Indian decent had different GJB2 mutations than the remainder of individuals tested. Patients of Asian, Italian, Spanish, Polish and Armenian decent were not found to carry mutations in GJB2 or the common GJB6-D13S1830 mutation.
This study represents the largest number of biallelic GJB2 mutations isolated in a group of paediatric cochlear implant users to date. Numerous and diverse GJB2 mutations were found in this multi-cultural group of children. Even though GJB2 mutations have been widely reported in the literature, this discussion represents the first report of GJB2 mutations in a multi-ethnic population (Canadian), as compared with previous studies that investigated fairly homogeneous populations. The diversity of GJB2 mutations identified reinforces the importance of testing for changes in GJB2 by direct sequencing of the entire coding region rather than testing only for common mutations.