Bert van Zanten

The effectiveness of bilateral cochlear implants for severe-to-profound deafness in children: a systematic review.

Objective: To assess the clinical effectiveness of bilateral cochlear implantation compared with unilateral cochlear implantation alone or with a contralateral hearing aid (bimodal stimulation), in children with severe-to-profound hearing loss. Recently, the National Institute for Health and Clinical Excellence (NICE) in the U.K. has conducted a systematic review on cochlear implantation. We decided to update the pediatric part of the NICE review. Data Sources: The electronic databases MEDLINE and Embase were searched for European, North American, and Australasian studies published between October 2006 and June 2009. Reference lists of the included articles were also searched for relevant articles. Study Selection: Studies were included if they comprised data on comparisons between bilateral cochlear implantation and unilateral cochlear implantation and/or bilateral cochlear implantation and bimodal stimulation, in children with severe-to-profound sensorineural hearing loss. The following outcome measures were analyzed: audiological, speech perception, speech production, functional capacities, health-related quality of life, and/or educational outcomes. Data Extraction: Characteristics of the participants, interventions, outcomes, and methodological comments were entered into data extraction forms and the level of evidence was assessed. Data Synthesis: Results were standardized for each outcome measure by calculating a standardized mean difference (effect size). Conclusion: Effect sizes could not be pooled because of the heterogeneity of the studies. Therefore, we presented the results qualitatively. Although the level of evidence was low, the advantages of bilateral cochlear implants corresponded with the primary benefits of bilateral hearing, that is, improved speech perception in quiet and noise. Localization results were less consistent. No data on audiologic, speech production, or educational outcomes were available.

ATP8B1 is essential for maintaining normal hearing

ATP8B1 deficiency is caused by autosomal recessive mutations in ATP8B1, which encodes the putative phospatidylserine flippase ATP8B1 (formerly called FIC1). ATP8B1 deficiency is primarily characterized by cholestasis, but extrahepatic symptoms are also found. Because patients sometimes report reduced hearing capability, we investigated the role of ATP8B1 in auditory function. Here we show that ATP8B1/Atp8b1 deficiency, both in patients and in Atp8b1G308V/G308V mutant mice, causes hearing loss, associated with progressive degeneration of cochlear hair cells. Atp8b1 is specifically localized in the stereocilia of these hair cells. This indicates that the mechanosensory function and integrity of the cochlear hair cells is critically dependent on ATP8B1 activity, possibly through maintaining lipid asymmetry in the cellular membranes of stereocilia.

Prevalence of hearing loss in 1598 adults with an intellectual disability: Cross-sectional population based study

A cross-sectional epidemiological study on prevalence of hearing loss was carried out in an age- and Downs syndrome- stratified random sample of 1598 persons drawn from a base population of 9012 persons, representative of the Dutch adult population of intellectual disability (ID) service users. The re-weighted population prevalence is 30.3% (95% confidence interval [CI]: 27.7–33.0%). Subgroup prevalences range from 7.5% (95% confidence interval [CI]: 3.6–13.3) in the subgroup aged 18–30 years with ID by other causes than Downs syndrome, up to 100% (95% CI: 79.4–100%) in adults over 60 years of age with Downs syndrome. Downs syndrome (OR 5.18, 95% CI 3.80–7.07) and age were confirmed to be risk factors. Age-related increase in prevalence in persons with Downs syndrome appears to occur approximately three decades earlier, and in persons with ID by other causes approximately one decade earlier than in the general population. Sumario Se realizó un estudio epidemiológico transversal sobre hipoacusia con una muestra aleatoria estratificada por edad, en 1598 personas con síndrome de Down, tomadas de una población base de 9012 personas, representativas de los usuarios de servicios para discapacidad intelectual (ID) de adultos en Holanda. La prevalencia de población reconsiderada es de 30.3% (95% de intervalo de confianza revalorada [CI]: 27.7–33.0%). El rango de prevalencia de los subgrupos varió de 7.5% (95% de intervalo de confianza [CI]: 3.6–13.3) en el subgrupo de 18–30 años con ID por otras causas diferentes al S. de Down, hasta el 100% (95% CI: 79.4–100%) en adultos mayores a 60 años con S. de Down. El S. de Down (OR 5.18, 95% CI 3.80–7.07) y la edad se confirmaron como factores de riesgo. El incremento en la prevalencia relacionado con la edad en personas con S. de Down, parece ocurrir aproximadamente tres décadas más temprano y en personas con ID por otras causas, aproximadamente una década más temprano que en la población general.

Audiological performance after cochlear implantation: a 2-year follow-up in children with inner ear malformations

Conclusions: Open-set speech perception in children with an inner ear malformation is equal to that of other congenitally deaf children after an average of 2 years follow-up. Objective: To analyze audiological performance after cochlear implantation in a sample of children with radiographically detectable malformations of the inner ear compared to performance in prelingually deafened children at large. Materials and methods: Nine children with osseous inner ear malformations were compared to 22 congenitally deaf children, all of whom underwent cochlear implantation. All subjects were tested on their electrical evoked compound action potential. Speech perception tests were performed using the monosyllabic trochee polysyllabic test without visual support and the open-set monosyllabic wordlist. Results: In all, 20% of the congenitally deaf children in our center study have inner ear abnormalities. Inner ear malformations were limited to incomplete partition of the cochlea; none of the subjects had common cavity malformations. Electrical compound action potentials were successfully recorded in both groups intraoperatively. Speech perception tests on open-set speech yielded an average of 48.8% (SD 21.2%) in the group of children with inner ear malformations vs 54.5% (SD 21.1%) in congenitally deaf children. In four of nine cases with an inner ear malformation we encountered a minor CSF leak.

The Effectiveness of Bilateral Cochlear Implants for Severe-to-Profound Deafness in Children

Objective Assessment of the clinical effectiveness of bilateral cochlear implantation compared with unilateral cochlear implantation or bimodal stimulation, in adults with severe-to-profound hearing loss. In 2007, the National Institute for Health and Clinical Excellence (NICE) in the U.K. conducted a systematic review on cochlear implantation. This study forms an update of the adult part of the NICE review. Data Sources The electronic databases MEDLINE and Embase were searched for English language studies published between October 2006 and March 2011. Study Selection Studies were included that compared bilateral cochlear implantation with unilateral cochlear implantation and/or with bimodal stimulation, in adults with severe-to-profound sensorineural hearing loss. Speech perception in quiet and in noise, sound localization and lateralization, speech production, health-related quality of life, and functional outcomes were analyzed. Data Extraction Data extraction forms were used to describe study characteristics and the level of evidence. Data Synthesis The effect size was calculated to compare different outcome measures. Conclusion Pooling of data was not possible because of the heterogeneity of the studies. As in the NICE review, the level of evidence of the included studies was low, although some of the additional studies showed less risk of bias. All studies showed a significant bilateral benefit in localization over unilateral cochlear implantation. Bilateral cochlear implants were beneficial for speech perception in noise under certain conditions and several self-reported measures. Most speech perception in quiet outcomes did not show a bilateral benefit. The current review provides additional evidence in favor of bilateral cochlear implantation, even in complex listening situations.

Characteristics of Hearing Loss in HDR (Hypoparathyroidism, Sensorineural Deafness, Renal Dysplasia) Syndrome

Haploinsufficiency of the zinc finger transcription factor GATA3 causes the triad of hypoparathyroidism, deafness and renal dysplasia, known by its acronym HDR syndrome. The purpose of the current study was to describe in detail the auditory phenotype in human HDR patients and compare these to audiometrical and histological data previously described in a mouse model of this disease. Pure tone audiometry, speech audiometry, speech in noise, auditory brainstem responses and transiently evoked otoacoustic emissions were measured in 2 patients affected by HDR syndrome. Both patients were affected by a moderate-to-severe sensorineural hearing loss. Speech reception thresholds were shifted and speech recognition in noise was disturbed. No otoacoustic emissions could be generated in either patient. Auditory brainstem response interpeak intervals were normal. The human and murine audiological phenotypes seem to correspond well. Hearing loss in HDR syndrome is moderate to severe, seems to be slightly worse at the higher end of the frequency spectrum and may be progressive with age. The absence of otoacoustic emissions and the loss of frequency selectivity suggest an important role for outer hair cells in causing the hearing loss.

Combined sensory impairment (deaf-blindness) in five percent of adults with intellectual disabilities.

Our purpose in this cross-sectional study with 1,598 adult clients who had intellectual disabilities was to obtain valid prevalences of sensory impairments and to identify associations. The diagnoses were made through ophthalmologic and audiometric assessments, applying WHO/IASSID definitions. Re-weighted prevalences were 5.0% (95% CI 3.9- 6.2%) for the total adult population; 2.9% (1.9-4.1), less than 50 years; and 11.0% (7.9- 14.7), 50 years and over. Apart from being 50 years of age and over, p = .000, risk factors were more severe intellectual disability, p = .0001, and Down syndrome, p = .001. Results show that the risk of combined sensory impairment in this population is considerably increased compared with the general population. Part of the underlying conditions are treatable or can be rehabilitated. However, the complete diagnosis had been identified in only 12%.

Is hearing loss a feature of Joubert syndrome, a ciliopathy?

OBJECTIVE To assess if hearing loss is a feature of Joubert syndrome (JBS), one of the ciliopathies and therefore possibly associated with hearing loss. DESIGN Retrospective case series. SETTING University Childrens Hospital. PATIENTS Dutch patients with JBS. MAIN OUTCOME MEASURES Audiological data. RESULTS Data from 22 Dutch Joubert syndrome (JBS) cases (17 males, 5 females) aged 3-40 years were available. Audiological tests were successfully performed in 14 cases. Three cases (aged 17-26 years) showed very mild sensorineural hearing loss (SNHL) at different frequencies. Conductive hearing loss due to middle ear infections occurred frequently in young JBS children (6 out of 22 cases). In three cases (aged 3-13 years) the parents reported the child was hypersensitive to sound. CONCLUSION We found no evidence for significant hearing loss in Joubert syndrome patients. However, given the compromised speech development in JBS, conductive hearing loss due to middle ear infections should be treated vigorously. SNHL at a later age cannot be excluded on the basis of our data, given the sample size. Three of the older cases showed discretely increased hearing thresholds. Analogous to the ciliopathy Bardet-Biedl syndrome, where hearing thresholds were reported to be subclinically increased in a group of adolescents patients, we recommend follow-up of JBS patients in view of the possibility of progressive, late-onset SNHL.

From Neonatal Hearing Screening to Intervention: Results of the Dutch Program for Neonatal Hearing Screening in Well Babies

In the Netherlands, Youth Health Care services (YHC) have been carrying out neonatal hearing screening (NHS) in newborns since 2006. The aim of the NHS is to identify children with permanent hearing loss, so that intervention can be started before the age of 4 months. Early detection of hearing loss is important, as children who start intervention early have been shown to develop better. This article describes the structure and performance of the NHS carried out by the YHC, the quality of the program, and the timeliness of the start of intervention. Since its implementation, the NHS has been audited annually in order to monitor the program’s quality. Monitoring reports and data from the Dutch Foundation for the Deaf and Hard of Hearing Child were used in this study. For many years, results have shown the NHS to be a stable screening program of high quality. The participation rate is high, refer percentage low, and the timeliness of the program is continually improving. Although the timeliness of post screening diagnostics and intervention need most improvement as they do not always meet the target times, this has improved over recent years.