Psychosocial work environment,hearing impairment and health

This article summarizes results from a study of hearingimpaired men and women in the labour force in Sweden. A questionnaire about psychosocial work environment (in accordance with the Demand-Control Model), health and wellbeing was sent out and answered by 445 hearingimpaired people, 20-64 years of age. A large reference group had previously answered the same questionnaire. The results indicate that imbalances between demand and control (i.e. high demand and low control, so-called high stress work type) is more common among hearingimpaired people than in the reference group. The outcome of the combination high demand and low control among hearing-impaired people is (much) worse than among hearing-impaired people with other work types ( passive, active, low stress). Hearing-impaired people with the high-stress work type more frequently report bad physical health status and psychological wellbeing regarding a number of indicators. There is, moreover, a tendency for women to be worse off than men. Our data suggest that those involved in audiological rehabilitation should pay great attention to hearing-impaired people with jobs that can be characterized as high stress.     

Head Diffraction Effects on Ear-Level Hearing Aids

In this paper, head baffle and head shadow effects were measured at a front-oriented and at a back-oriented micro-phone in a hearing aid casing when worn by human subjects and when placed on a dummy head. Some differences in head baffle and head shadow effects were observed for the front- and back-oriented microphones in that greater head baffle effects were observed at the front microphone than at the back microphone while the reverse was true in terms of head shadow effects. Results obtained with the hearing aid mounted on a dummy head were similar in some respects and in other respects they differed from those observed when the hearing aid was worn by six subjects. Comparison of the results obtained in this study with the data of Wiener measured at the entrance to the ear canal indicated smaller head baffle effects but larger head shadow effects at the hearing aid microphone than at the canal entrance. Finally, it is suggested that reproduction of frequencies above 2000 Hz and that a resonance peak at about 3000 Hz in the frequency response curve of a hearing aid may be beneficial to the wearer     

Débordement de masquage normal et anormal sur les aigus

Upward Spread of Masking in Normal and Impaired Ears

Upward spread of masking was studied for normals and sensorineurally hearing-impaired subjects with high-frequency hearing loss. Hearing-impaired listeners were recruited in such a way as to present normal hearing on the frequency of the masker, that is a narrow band of noise centered at 1 000 Hz. Levels of the masker were set at 70, 80 and 90 dB, respectively. Results first indicated the presence of a relationship between masked and elevated absolute thresholds for a masker level of 70 dB. At masker levels of 80 and 90 dB, hearing-impaired listeners showed excessive upward spread of masking in spite of normal hearing sensitivity at the masker frequency: with 80 and 90 dB of noise, upward spread of masking grew, respectively, 2.6 and 1.6 times faster than in normals. Furthermore, excessive upward spread of masking was shown to progress as a function of hearing loss. Results were interpreted as additional evidence of abnormal frequency selectivity in sensorineurally hearing-impaired listeners.     

桐乡市2006-2010年41546例新生儿听力筛选结果统计分析

目的 了解我市近5年来新生儿听力筛查的基本情况,探讨进一步提高新生儿听力筛查工作水平与减少听力残疾儿发生的方法.方法 应用诱发畸变耳声发射（DPOAE）对我市9家医院产科2006年1月1日至2010年12月31日住院分娩的41 546名新生儿进行听力筛查,可疑者转嘉兴市听力诊断中心做听性脑干诱发电位（ABR）检查.结果 连续5年筛查率均在98%以上,复筛率94.00%～98.25%,ABR检查确诊257例,听力障碍5年平均发病率为6.09‰.首次筛查假阳性率8.31%,最终复筛的假阳性率0.92%.结论 新生儿听力筛查的必要性与重要性在我市广大群众中已深入人心,新生儿听力障碍发病率呈明显的逐年下降趋势.加强围产保健工作与流动人口中的孕产妇管理,减少与新生儿听力障碍有关的高危因素可使新生儿听力障碍发病率进一步下降.     

Modelling the risk of noise-induced hearing loss among military pilots

Noise is a significant risk factor in aviation, especially in military aviation. Even though our earlier studies have shown that the risk of noise-induced hearing loss (NIHL) among military pilots is small and the monitoring of their hearing is effective, we still need to develop methods of assessing the risk of NIHL more effectively at both the general and individual levels. In addition, many other risk factors are considered to contribute to the development of hearing impairment. The novel NoiseScan data management system enables assessment of the risk of developing hearing impairment on the basis of known risk factors. This study investigates the risk of hearing impairment among Finnish Air Force pilots using reasonably accurate noise exposure data and other risk factors for hearing impairment. This risk is also compared with that of industrial workers, whose risk followed the ISO 1999 prediction. Hearing among Finnish military pilots turned out to be better than predicted by the ISO 1999 model. The industrial workers had a larger number of risk factors than the pilots. Owing to the small number of risk factors, the hearing of pilots corresponds to approximately the 80th percentile, being 9-13 dB better than the 50th percentile obtained with the industrial population.     

Three-dimensional structure of outer hair cell pillars

Conclusions. Electron tomography was used to generate three-dimensional reconstructions of the pillars that connect the cell membrane with the cytoskeleton of the outer hair cell. Results are consistent with the hypothesis that pillars are important for mechanically linking the membrane with the cytoskeleton. Objective: To make a qualitative assessment of the morphology of the sub-membrane pillars of cochlear outer hair cells. Materials and methods. Guinea pig cochleae were fixed and prepared for electron microscopy using protocols described previously. Sections were imaged on an electron microscope equipped with a goniometer. The specimens were tilted through a range of 120°, and an image was acquired at each tilt angle. Filtered back-projection was used to generate three-dimensional reconstructions. Results. Twelve individual pillars were successfully reconstructed. Pillars often connect to the cell membrane through a thin segment, and to the cytoskeleton through a forking structure that may form a central cavity.     

Outcomes in adults implanted with the FLEXsoft electrode

Conclusion. Achieving deep insertions, as well as good speech perception results, the FLEX^soft electrode array allows for some preservation in subjects with measurable low frequency hearing, even after a period of time. This opens the door for future research in electrode design, hearing preservation research and drug delivery systems. Objectives. The FLEX^soft electrode is designed to be atraumatic to the structures of the cochlea during deep insertion of a cochlear implant electrode. This paper reports on the surgical and functional outcomes in implantations with the FLEX^soft electrode array. Patients and methods. Twenty-three adult subjects received a FLEX^soft electrode array and were assessed on speech perception tests (monosyllables, sentences in quiet and in noise), a subjective questionnaire (Nijmegen Cochlear Implant Questionnaire) and a pure-tone audiogram. Results at 1, 3, 6 and 12 months post first fitting were compared to scores from the preoperative interval. Results. Surgery was uneventful in all cases, the surgical handling was satisfactory and correct position of the electrode was achieved in all cases. Hearing could be preserved (as determined by the audiogram) in half of the subjects who had measurable audiograms preoperatively at the 1 month test interval, and in a quarter of subjects after 12 months of device use, despite deep insertion of the electrode. Speech perception scores showed significant improvement over time, as did quality of life scores, and were comparable to results with the standard electrode array as used in the COMBI 40+ and PULSARCI¹⁰⁰.     

A longitudinal evaluation of hearing and ventilation tube insertion in patients with primary ciliary dyskinesia

IntroductionPrimary ciliary dyskinesia (PCD) is an autosomal recessive genetic disease, which primarily manifests with oto-sino-pulmonary symptoms. Otitis media with effusion (OME) is common from early childhood. The existing literature on OME management in PCD is conflicting.The goals of the present study were firstly to evaluate the long-term hearing in PCD patients and secondly to determine the influence of ventilation tube (VT) insertion on hearing and postoperative otorrhoea.MethodsA longitudinal retrospective study extracting the hearing level (pure tone average (0.5, 1, 2, 4 kHz, PTA)) and tympanometry from the medical records. Furthermore, the patient files were reviewed for VT insertion and postoperative otorrhoea. Postoperative otorrhoea was defined prolonged when it lasted for four weeks or longer.ResultsFifty-seven patients were identified in a 30-year period, age 2–72 years, and 278 audiometries were evaluated. The median number of audiometries per patient was 3 (range 1–29) and the median follow-up was 60 months (range 0–351 months). The mean PTA was 34 dB HL in patients below six years of age and improved significantly (p < 0.0001) with age. VT insertion improved hearing; however, 48% of patients with VT insertion experienced prolonged otorrhoea.ConclusionIn this study of PCD patients the hearing improved as a function of age as well as following VT insertion. However, VT insertion was also associated with prolonged otorrhoea.     

Using zebrafish as a model to study the role of epigenetics in hearing loss

Introduction: The rapid progress of bioinformatics and high-throughput screening techniques in recent years has led to the identification of many candidate genes and small-molecule drugs that have the potential to make significant contributions to our understanding of the developmental and pathological processes of hearing, but it remains unclear how these genes and regulatory factors are coordinated. Increasing evidence suggests that epigenetic mechanisms are essential for establishing gene expression profiles and likely play an important role in the development of inner ear and in the pathology of hearing-associated diseases. Zebrafish are a valuable and tractable in vivo model organism for monitoring changes in the epigenome and for identifying new epigenetic processes and drug molecules that can influence vertebrate development.

Areas covered: In this review, the authors focus on zebrafish as a model to summarize recent findings concerning the roles of epigenetics in the development, regeneration, and protection of hair cells.

Expert opinion: Using the zebrafish model in combination with high-throughput screening and genome-editing technologies to investigate the function of epigenetics in hearing is crucial to help us better understand the molecular and genetic mechanisms of auditory development and function. It will also contribute to the development of new strategies to restore hearing loss.