Societal costs of hearing disorders: A systematic and critical review of literature

Abstract Objective: The objective of this study was to perform a critical and systematic literature review of studies on societal costs due to hearing disorders. Design: We used predefined search terms and inclusion/exclusion criteria. Systematic searches were conducted in Medline, Cochrane Library, Google Scholar, and other relevant websites. The review included studies written in English or Swedish between 1995 and the end of January 2012. Study sample: We identified four published studies and four reports that met the pre-defined inclusion criteria. Results: Swedish cost studies primarily focused on costs of hearing aids. International studies with a societal perspective used different costing approaches and were limited to specific patient populations. Hearing disorders impact the social welfare system more than the medical care system. Indirect costs account for the major part and direct medical costs for a minor part of the total costs of hearing disorders. Conclusions: There is a need for further studies estimating societal costs for all degrees of hearing disorders, in particular since a large part of the people with hearing disorders are of working age.     

Intratympanic steroid treatment: a review.

OBJECTIVE: To review published literature regarding the use of intratympanic steroids in the treatment of Meniere's disease and sudden sensorineural hearing loss and to make recommendations regarding their use based on the literature review. DATA SOURCES: Literature review from 1996 to 2003, PubMed, Medline Plus, and Web of Science. STUDY SELECTION: Retrospective case series and uncontrolled prospective cohort studies were the only types of studies available for review. CONCLUSION: On the basis of the available literature, a weak recommendation is made to use intratympanic steroid treatment of sudden hearing loss if oral steroid therapy fails or is contraindicated. The available studies regarding intratympanic steroid treatment of Meniere's disease and tinnitus are inadequate to answer the question of the efficacy of this treatment for these conditions. Higher quality studies are needed.     

Drug-induced otoxicity: current status

We carried out a review of the literature published over the last 10 years on drug-induced ototoxicity by means of a Medline search using the terms 'clinical ototoxicity' for the period January 1990 to September 2000 and found 414 published articles. In order to summarize the content of these articles, we asked ourselves a series of nine questions and answered them based on the most widely-held views and those we considered of greatest interest in the articles reviewed. The questions asked were: what are the most commonly used ototoxic drugs? what is the site of action of ototoxic drugs? what is the importance of the dose and dosing interval? does age influence ototoxicity? are all humans equally prone to the ototoxic effects of drugs? are there substances that are protective against ototoxicity? can hearing loss be monitored? should hearing loss be attributed to ototoxic drugs in all cases? and is ototoxicity in animals the same as in humans?     

Ototoxicity (cochleotoxicity) classifications: A review

Objective: Drug-mediated ototoxicity, specifically cochleotoxicity, is a concern for patients receiving medications for the treatment of serious illness. A number of classification schemes exist, most of which are based on pure-tone audiometry, in order to assist non-audiological/non-otological specialists in the identification and monitoring of iatrogenic hearing loss. This review identifies the primary classification systems used in cochleototoxicity monitoring. By bringing together classifications published in discipline-specific literature, the paper aims to increase awareness of their relative strengths and limitations in the assessment and monitoring of ototoxic hearing loss and to indicate how future classification systems may improve upon the status-quo. Design: Literature review. Study sample: PubMed identified 4878 articles containing the search term ototox*. Results: A systematic search identified 13 key classification systems. Cochleotoxicity classification systems can be divided into those which focus on hearing change from a baseline audiogram and those that focus on the functional impact of the hearing loss. Conclusions: Common weaknesses of these grading scales included a lack of sensitivity to small adverse changes in hearing thresholds, a lack of high-frequency audiometry (>8 kHz), and lack of indication of which changes are likely to be clinically significant for communication and quality of life.     

Knowledge and attitude of parents/caregivers towards hearing loss and screening in newborns – a systematic review

Objective: The parents/caregivers of a newborn play a pivotal role in the process of hearing screening and intervention. The decisions taken by them depend on their knowledge and attitude. The purpose of this study was to review the literature systematically on knowledge and attitude of parents/caregivers towards infant hearing loss and newborn hearing screening. Design: A systematic search was conducted using electronic databases for the periods from 1990 to March 2016. Two authors scrutinized the studies and extracted the data based on predetermined criteria. Study sample: Ten studies. Results: Ear discharge was correctly identified as a risk factor for hearing loss along with measles, drugs/medication, family history, congenital causes and noise exposure. The studies revealed mixed results for knowledge about newborn hearing screening. Overall, the parents/caregivers showed positive attitudes towards hearing screening and intervention options. However, due to heterogeneity in the studies, it’s hard to derive a conclusion. Conclusions: The present review sheds light on the common areas of misconception among parents/caregivers about risk factors of infant hearing loss and newborn hearing screening. The review also draws attention to the need to have more studies exploring this knowledge and attitude of parents/caregivers among diverse populations.     

Effectiveness of counseling-based adult group aural rehabilitation programs: a systematic review of the evidence

A systematic evidence-based review was conducted to examine the effectiveness of counseling and communication strategy-oriented group adult aural rehabilitation (AR) programs. The literature search for relevant articles focused on studies that (1) employed adults with hearing impairment; (2) used a group aural rehabilitation program that emphasized counseling and communication strategies; (3) utilized a randomized controlled trial, quasi-experimental, or non-intervention cohort design; (4) employed an outcome measure that assessed some aspect of personal adjustment, perceived hearing handicap, or hearing aid benefit and/or satisfaction; and (5) were published in a refereed journal. Twelve articles were found that met these inclusion criteria. Analysis of the 12 studies led to the following conclusion: there is reasonably good evidence that participation in an adult AR program provides short-term reduction in self-perception of hearing handicap and potentially better use of communication strategies and hearing aids. It is less clear whether this advantage over provision of hearing aids alone persists over time.     

Organic solvents and hearing loss: The challenge for audiology

Organic solvents have been reported to adversely affect human health, including hearing health. Animal models have demonstrated that solvents may induce auditory damage, especially to the outer hair cells. Research on workers exposed to solvents has suggested that these chemicals may also induce auditory damage through effects on the central auditory pathways. Studies conducted with both animals and humans demonstrate that the hearing frequencies affected by solvent exposure are different to those affected by noise, and that solvents may interact synergistically with noise. The present article aims to review the contemporary literature of solvent-induced hearing loss, and consider the implications of solvent-induced auditory damage for clinical audiologists. Possible audiological tests that may be used when auditory damage due to solvent exposure is suspected are discussed.     

Bilateral paediatric cochlear implants: A critical review

A recent trend has been the implantation of bilateral cochlear implants (CIs) for children with severe to profound hearing loss. A review of available research on bilateral CIs was conducted to determine the support for this trend. A replicable review was undertaken to evaluate published research studies that examined the effectiveness of bilateral paediatric cochlear implantation. Databases, reference lists, and journals were searched for relevant documents using a pre-determined search protocol. Twenty-nine articles met the review's inclusion criteria and were retrieved and reviewed. This review adds to the previously published reviews on the topic by identifying additional paediatric studies. Sound localization and speech recognition in noise appear to be improved with bilateral compared to unilateral cochlear implants. Similarly, evoked potential measures suggest improved morphology when the second CI is implanted early. Well-designed and controlled studies that explore a variety of outcomes including cost-effectiveness, quality of life, speech, language, and psycho-educational measures should be further explored in order to provide additional support for parents and clinicians confronted with the bilateral cochlear implant decision.     

Delivery of drugs to the inner ear

PURPOSE OF REVIEW: Inner ear delivery of medicines has been a rapidly expanding field in otolaryngology. This technique provides a minimally invasive way of managing a number of otolaryngologic diagnoses and promises to provide a therapeutic option for previously untreatable disorders. The purpose of this review is to examine the literature that has been published recently (since January of 2005) in this field and to explore how this new literature has impacted on current practices. RECENT FINDINGS: While there was a significant volume of work done in this area from 1995 to 2004, publication in this area has slowed considerably. The literature focuses on two areas: the treatment of Ménière's disease with gentamicin and the treatment of sudden sensorineural hearing loss with steroids. The most promising area in this field, which is the development of new medicines to treat a variety of disorders, has not progressed over the last 2 years. SUMMARY: Recent peer-reviewed publications have not had a significant impact on the transtympanic treatment of Ménière's disease or sudden sensorineural hearing loss. We will review the current practices in these two areas, discuss the newest developments and examine how we can progress the field over the next several years.     

Bone-conducted sound: physiological and clinical aspects.

OBJECTIVE: The fact that vibration of the skull causes a hearing sensation has been known since the 19th century. This mode of hearing was termed hearing by bone conduction. Although there has been more than a century of research on hearing by bone conduction, its physiology is not completely understood. Lately, new insights into the physiology of hearing by bone conduction have been reported. Knowledge of the physiology, clinical aspects, and limitations of bone conduction sound is important for clinicians dealing with hearing loss and is the purpose of this review. DATA SOURCES: The data were compiled from the published literature in the areas of clinical bone conduction hearing, bone conduction hearing aids, basic research on bone conduction physiology, and recent research on bone conduction hearing from our laboratory. CONCLUSION: Five factors contributing to bone conduction hearing have been identified: 1) sound radiated into the external ear canal, 2) middle ear ossicle inertia, 3) inertia of the cochlear fluids, 4) compression of the cochlear walls, and 5) pressure transmission from the cerebrospinal fluid. Of these five, inertia of the cochlear fluid seems most important. Bone conduction sound is believed to reflect the true cochlear function; however, certain conditions such as middle ear diseases can affect bone conduction sensitivity, but less than for air conduction. The bone conduction route can also be used for hearing aids; since the bone conduction route is less efficient than the air conduction route, bone conduction hearing aids are primarily used for hearing losses where air conduction hearing aids are contraindicated.     

Hearing function of gold miners with and without a history of tuberculosis treatment: a retrospective data review

IntroductionSouth Africa has a high prevalence of co-existing tuberculosis and HIV. As ototoxicity linked to the treatments for these conditions occurs with concomitant exposure to other ear toxins such as hazardous noise exposure, it is important to investigate the combination impact of these toxins. Limited published evidence exists on the co-occurrence of these conditions within this population.ObjectivesThe objective of this study was to compare the hearing function of gold miners with (treatment group) and without (non-treatment group) the history of tuberculosis treatment, in order to determine which group had increased risk of noise induced hearing loss. Furthermore, possible influence of age and HIV in these two groups was examined.MethodsA retrospective record review of 102 miners’ audiological records, divided into two groups, was conducted, with data analyzed both qualitatively and quantitatively.ResultsFindings suggest that gold miners with a history of tuberculosis treatment have worse hearing thresholds in the high frequencies when compared to those without this history; with evidence of a noise induced hearing loss notch at 6000 Hz in both groups. Pearson's correlations showed values between 0 and 0.3 (0 and −0.3) which are indicative of a weak positive (negative) correlation between HIV and hearing loss, as well as between hearing loss and age in this population.ConclusionsCurrent findings highlight the importance of strategic hearing conservation programs, including ototoxicity monitoring, and the possible use of oto-protective/chemo-protective agents in this population.     

Differences between acoustic trauma and other types of acute noise-induced hearing loss in terms of treatment and hearing prognosis

Abstract

Objectives: To evaluate the differences between acoustic trauma (AT) and other types of acute noise-induced hearing loss (ANIHL), we performed a literature search and case reviews.

Methods: The literature search based on online databases was completed in September 2016. Articles on ANIHL and steroid treatment for human subjects were reviewed. The source sounds and treatment sequelae of our accumulated cases were also reviewed. Hearing loss caused by gun-shots and explosions was categorized into the AT group, while hearing loss caused by concerts and other noises was categorized into the ANIHL group.

Results: Systemic steroid treatment did not appear to be effective, at least in the AT group, based on both the literature and our case reviews. However, effective recovery after treatment including steroids was observed in the ANIHL group. The difference in hearing recovery between the AT and ANIHL groups was statistically significant (p?=?.030), although differences in age, days from the onset to treatment and pretreatment hearing levels were not significant.

Conclusions: Hearing recovery from AT is very poor, whereas, ANIHL is recoverable to some extent. Therefore, it is essential to differentiate between these two groups for accurate prediction of the hearing prognosis and evaluation of treatment effects.     

Auditory research involving antioxidants

PURPOSE OF REVIEW: The role of antioxidants in the management of hearing loss has generated considerable interest over the past several years. Research efforts in this field have yielded many new insights into the molecular and cellular nature of several types of hearing impairment, including age-related, noise-induced, and drug-induced hearing loss. The objective of this paper is to highlight some of the important studies published over the past several years that have further contributed to our understanding of the mechanism of antioxidants in attenuating hearing loss. RECENT FINDINGS: There is compelling evidence to suggest that antioxidant therapy is beneficial in attenuating, improving, or reversing the effects of several types of acquired hearing loss. Cellular and subcellular changes resulting from these types of hearing impairment are remarkably similar and seem to have a common putative mechanism of oxidative stress and damage. Recent studies have lent further credibility to the notion that antioxidant therapy can be of considerable benefit in the treatment of hearing loss. The increasing body of literature pertaining to human studies will shed further light into this fascinating area of research. SUMMARY: This review elucidates the role of antioxidants in hearing loss and illustrates the continued evolution of research efforts in this field.     

Cochlear implantation for single-sided deafness: the outcomes. An evidence-based approach

The aim of the present paper is to critically review the current evidence on the efficacy of cochlear implantation as a treatment modality for single-sided deafness (SSD), and/or unilateral tinnitus. Systematic literature review in Medline and other database sources was conducted along with critical analysis of pooled data. The study selection includes prospective and retrospective comparative studies, case series and case reports. The total number of analyzed studies was 17. A total of 108 patients with SSD have been implanted; 66 patients due to problems associated with SSD, and 42 primarily because of debilitating tinnitus. Cochlear implantation in SSD leads to improved sound localization performance and speech perception in noise from the ipsilateral side with an angle of coverage up to (but not including) 90^° to the front, when noise is present in the contralateral quartile (Strength of recommendation B). Speech and spatial hearing also subjectively improve following the insertion of a cochlear implant (Strength of recommendation B); this was not the case regarding the quality of hearing. Tinnitus improvement was also reported following implant placement (Strength of recommendation B); however, patients need to be advised that the suppression is mainly successful when the implant is activated. The overall quality of the available evidence supports a wider use of cochlear implantation in SSD following appropriate selection and counseling (overall strength of recommendation B). It remains to be seen if the long-term follow-up of large number of patients in well conducted high quality studies will confirm the above mentioned results.     

Effectiveness of questionnaires for screening hearing of school-age children: A comprehensive literature review

Abstract

Objective: The purpose of this study was to review the literature on the effectiveness of parent or teacher-completed questionnaires as a tool to screen school-aged children for permanent hearing loss. Design: A rapid evidence assessment was completed to provide a summary of information published between 1980 and 2013 in English or Spanish. To identify relevant publications, a database search was conducted using nine databases. Study sample: Seven studies were identified for inclusion in the review. Results: Authors of three of the studies recommended use of the questionnaire as a method for screening hearing in school-aged children, and authors of four of the studies did not recommend use of the questionnaire. However, only one of the seven studies provided good evidence that questionnaires are an effective way of identifying hearing loss among children. Conclusions: There is insufficient evidence that parent or teacher completed questionnaire screening can be reliably used to identify children in need of further hearing assessment. It is clear that more research is needed before concluding that questionnaires are an effective and low-cost tool for use to screen children for permanent hearing loss.     

A review of acoustic tumors: 1983-1988

This is a review of the English literature relative to acoustic tumors from 1983 through 1988. In January of 1984, a similar article was published in this journal which reviewed the literature from 1979 through 1982. We have selected what we consider the most important articles from the hundreds that were published on this subject. Many other significant papers are not discussed. The material is presented in 11 categories: diagnosis, histopathology, treatment, hearing preservation, facial nerve preservation and repair, von Recklinghausen's disease and bilateral tumors, nonacoustic cerebellopontine angle tumors, instrumentation, basic research, complications of surgery, and miscellaneous topics. In each section the articles are briefly reviewed, and sometimes our personal point of view is expressed.     

Working in noise with a hearing loss: perceptions from workers, supervisors, and hearing conservation program managers

OBJECTIVE: Workers with hearing loss face special problems, especially when working in noise. However, conventional hearing conservation practices do not distinguish between workers with normal hearing versus impaired hearing. This study collected information from workers with self-reported noise exposure and hearing loss, supervisors of such workers, and hearing conservation program managers through focus groups and in-depth interviews to evaluate their perspectives on the impact of hearing loss on safety and job performance, the use of hearing protection, and information needed to appropriately manage hearing-impaired workers who work in noisy environments. RESULTS: Concerns about working in noise with a hearing loss could be grouped into the following 10 categories: impact on job performance, impact on job safety, impaired ability to hear warning signals, impaired ability to monitor equipment, interference with communication, stress and/or fatigue, impaired communication caused by hearing protector use, reduced ability to monitor the environment as the result of hearing protector use, concerns about future quality of life, and concerns about future employability. Mostly, there was an agreement between the perceptions of workers, supervisors, and hearing conservation program managers regarding difficulties associated with hearing loss and consequent needs. These findings suggest that noise-exposed workers with hearing loss face many of the same problems reported in the literature by noise-exposed workers with normal hearing, with additional concerns primarily about job safety as the result of a reduced ability to hear environmental sounds, warning signals, and so forth. CONCLUSIONS: The study outlines potential challenges regarding job safety and hearing conservation practices for noise-exposed, hearing-impaired workers. Awareness of these issues is a necessary first step toward providing appropriate protective measures for noise-exposed, hearing-impaired workers.