Further evidence for linkage of low-mid frequency hearing impairment to the candidate region on chromosome 4p16.3

We have investigated a three-generation family with an autosomal dominant low-mid frequency hearing loss. Audiograms show consistently a hearing threshold of 50+/-20 db hearing loss (HL) between 250 Hz and 1-2 kHz. Normal hearing level was reached between 3 and 6 kHz in all examined children. Adult patients show an additional hearing impairment (HI) in the mid and higher frequencies that seems to differ from presbyacusis. The HI is always bilateral and symmetrical. Genes causing non-syndromic autosomal-dominant deafness with HI in the low and mid frequencies were previously mapped to chromosome 4p16.3 (DFNA6, DFNA14) and chromosome 5q31 (DFNA1). After exclusion of linkage to DFNA1 on chromosome 5, we mapped the candidate gene region to the DFNA14 and DFNA6 loci, between the genetic markers D4S432 and D4S431, located on chromosome 4. This is a further family in which evident linkage of low-mid frequency HI to the candidate region on chromosome 4p16.3 has been found.     

A new family with the Townes-Brocks syndrome

We describe a new family with the Townes-Brocks syndrome, a dominantly inherited syndrome of anal, urorenal, ear and limb malformations. The proband shows the full spectrum of anomalies, including imperforate anus, prominent perineal raphe, rectoperineal fistula, triphalangeal thumb, preaxial hexadactyly, syndactyly, clinodactyly, preauricular protuberances, hypoplastic satyr ears, sensorineural hearing loss and urorenal anomalies. In contrast, the father shows only limb anomalies, sensorineural hearing loss and renal anomalies. Anorectal malformations, which are present in almost every patient with the Townes-Brocks syndrome, were absent in the father. This case report illustrates the intrafamilial variability of the Townes-Brocks syndrome. Consequently, careful examination of relatives of patients with this syndrome is necessary for the differential diagnosis with the sporadically inherited VA(C)TER(L) association.     

An exploration of how health care professionals understand experiences of deafness

Findings from recent deaf education intervention programmes with health care professionals emphasise the importance of sociocultural dimensions of medicine, pointing to the need to further investigate health professionals’ current understandings of deafness. Situated within a social constructionist and critical realist framework, we investigated health professionals’ understandings of deafness and experiences of providing health services in Australia to d/Deaf people. Through an inductive thematic analysis of 18 individual interviews with medical or allied health professionals, we identified an overarching theme we labelled hearingness as privileged, whereby professionals accounted for the quality of the health services available to d/Deaf people in Australia. The professionals recognised the services as not good enough and, through relating their efforts to do the best they can, and describing how the situation could always be better, it was evident that the professionals were negotiating a larger health system that disadvantages the needs of d/Deaf people for the needs of people with hearingness. We discuss the implications of working within a system that privileges hearingness.     

天津市职业性噪声暴露人群健康状况及其影响因素

目的了解天津市职业性噪声暴露人群健康状况,分析其影响因素,为指导和实施干预措施提供科学依据。方法采用χ~2检验和Logistic回归分析对天津市11 643名职业性噪声暴露人群健康资料及所在288家企业工作场所噪声监测数据进行分析。结果天津市职业性噪声暴露人群高频听力损失检出率33.81%,高血压检出率19.81%,心电图异常检出率12.11%,男性高频听力损失明显高于女性。高噪声暴露组工人高频听力损失检出率、女性工人心电图异常率均高于低暴露组(P0.05);随噪声接触工龄延长,高频听力损失检出率增加(P0.05).Logistic回归结果表明,年龄增加、工龄延长和高噪声暴露均为高频听力损失的独立危险因素(OR1.00,P0.05);高噪声暴露情况下作业工人高频听力损失率增加42.00%(男性)和29.00%(女性),工龄每增加5年作业工人听力损失率增加23.00%(男性)和147.00%(女)。此外,高噪声暴露可增加男性高血压和女性心电图异常的发病风险(OR1.00,P0.05)。结论天津市职业性噪声暴露人群高频听力损失较为严重,高噪声暴露是高频听力损失、男性高血压发病和女性心电图异常的危险因素,应当引起重视,采取积极措施,预防疾病的发生。     

Challenges for the application of optical stimulation in the cochlea for the study and treatment of hearing loss

Introduction: Electrical stimulation has long been the most effective strategy for evoking neural activity from bionic devices and has been used with great success in the cochlear implant to allow deaf people to hear speech and sound. Despite its success, the spread of electrical current stimulates a broad region of neural tissue meaning that contemporary devices have limited precision. Optical stimulation as an alternative has attracted much recent interest for its capacity to provide highly focused stimuli, and therefore, potentially improved sensory perception. Given its specificity of activation, optical stimulation may also provide a useful tool in the study of fundamental neuroanatomy and neurophysiological processes.

Areas covered: This review examines the advances in optical stimulation – infrared, nanoparticle-enhanced, and optogenetic-based – and its application in the inner ear for the restoration of auditory function following hearing loss.

Expert opinion: Initial outcomes suggest that optogenetic-based approaches hold the greatest potential and viability amongst optical techniques for application in the cochlea. The future success of this approach will be governed by advances in the targeted delivery of opsins to auditory neurons, improvements in channel kinetics, development of optical arrays, and innovation of opsins that activate within the optimal near-infrared therapeutic window.     

CT及MRI在感音神经性耳聋患者行人工耳蜗植入术前的应用价值

目的 探讨CT及MRI在感音神经性耳聋(SNHL)患者行人工耳蜗植入(CI)术前的应用价值.方法 回顾分析2012年11月至2016年11月安徽医科大学第二附属医院收治的87例拟行CI的SNHL患者的CT及MRI图像,结合Sennaroglu分类法进行影像分类诊断.结果 87例SNHL患者的174耳中,耳蜗畸形10耳,前庭导水管扩大28耳,半规管畸形2耳,内听道畸形1耳,中耳炎患者7例.结论 不同影像学检查在SNHL患者CI术前能提供多种信息,均对临床诊治有重要的作用.     

The auditory and vestibular toxicities induced by antiepileptic drugs

Introduction: Epilepsy is a chronic medical disease in one third of patients and is associated with comorbid adverse somatic conditions due to epilepsy itself or its long-term treatment with antiepileptic drugs (AEDs). Data from experimental, cross-sectional and prospective studies have evidence for the deleterious effect of some AEDs on the auditory and vestibular systems. These abnormalities may be reversible or irreversible.

Areas covered: This article review the evidence that long-term treatment with some antiepileptic drugs (AEDs) [e.g. carbamazepine, phenytoin, valproate, lamotrigine, gabapentin, vigabatrin and oxcarbazepine] (even in therapeutic drug doses) may result in tinnitus, phonophobia, sensorineural hearing loss, dizziness, ataxia, disequilibrium, imbalance, nystagmus, abnormalities in saccadic and pursuit eye movements and delayed conduction within the cochlea, auditory nerve and brainstem auditory pathways evidenced by abnormalities in Brainstem auditory evoked potentials and nystagmography recordings indicating auditory and central and/or peripheral vestibular dysfunctions.

Expert opinion: Identification of monitoring of patients at high risk for developing audio-vestibular manifestations is necessary for appropriate preventive and therapeutic measures.