Blocking Pro-Cell-Death Signal Pathways to Conserve Hearing

The programmed cell death of stress-damaged auditory hair cells can occur through a variety of signal pathways, and therapeutic modalities that block pro-cell-death pathways are being developed and evaluated for hearing preservation. Because of their ability to have both anti-inflammatory and anti-apoptotic actions, corticosteroids have long been used to protect against several types of acute sensorineural hearing loss. Other anti-apoptotic drugs that target the mitogen-activated protein kinase (MAPK)/c-Jun-N terminal kinase (JNK) signal cascade, such as D-JNKI-1 (AM-111) and SP600125, have produced promising results both in vitro and in laboratory animal studies, with AM-111 showing promise in preliminary clinical trials. Antioxidant drugs, e.g. sodium thiosulfate, N-acetylcysteine, and D-methionine, have been shown in animal studies to attenuate permanent threshold shifts in hearing by reducing oxidative stress. In addition to reviewing selected therapeutic trends for the conservation of hearing, we review our experiences with dexamethasone and D-JNKI-1 and report results from our current research.

from Audiology & Neuro-Otology

The effect of mild hearing loss on academic performance in primary school children

Objectives
To determine the prevalence of mild hearing loss and its association with academic performance among primary school children.

Patients and methods
A comparative cross sectional study was conducted on standard (grade) five school children in a state in Malaysia. Five schools were selected by using simple random sampling. There were three classes (A, B and C) of standard five in each school. Student’s selection into these classes was made by respective school administration based on their final term examination in standard four. Class A was for the best academic achievers while class C was for the poorest. Ear examinations were done followed by pure tone audiometry for confirmation of the hearing status. In this study, mild hearing loss was defined as an average threshold of 20–39 dB at 0.5, 1, 2 and 4 kHz. Data analysis was done using SPSS Version 12.0 software. Chi-square test was used to determine the association between mild hearing loss and academic performance. The significant level was set at p = 0.05.

Results
From a total of 257 students, 234 have completed the examinations (response rate = 91.0%). Fifty-three percent of them were boys while 47% were girls. A hundred and forty-nine (63.7%) of them were from class A while 85 (36.3%) were from class C. The prevalence of hearing loss in our school population was 15% (95% CI: 11.0–20.0%). Thirty-two (88.9%) of them were having conductive type. Out of the total, 38.9% were having problems in both ears. The students who have poor academic performance have been shown to be significantly associated with mild hearing loss (p < 0.001).

Conclusions
There was a high prevalence of mild hearing loss among primary school children. This problem could affect their academic performance. Therefore, hearing assessment is highly recommended to be done on every child especially to those who have poor academic achievement.

from the International Journal of Pediatric Otorhinolaryngology

Diabetes-related changes in auditory brainstem responses

Objectives/Hypothesis:
Determine effects on auditory brainstem response (ABR) of diabetes mellitus (DM) severity.

Study Design:
A cross-sectional study investigating DM severity and ABR in military Veteran subjects with (166) and without (138) DM and with no more than moderate hearing loss.

Methods:
Subjects were classified by three age tertiles (<50, 50-56, and 57+). DM severity was classified as insulin-dependent (IDDM), non-insulin-dependent (NIDDM), or no DM. Other DM measures included serum glucose, HbA1c, and several DM-related complications. ABR measures included wave I, III, and V latencies; I-III, III-V, and I-V latency intervals; and wave V amplitude; for each ear at three repetition rates (11, 51, and 71 clicks/second), and both polarities. Outcomes were stratified by age tertile and adjusted for pure tone threshold at 3 kHz. Repeated measures multivariate analysis of covariance modeled the ABR response at each repetition rate for DM severity (main effect) and hearing at 3 kHz (covariate). Modeled contrasts between ABR variables in subjects with and without DM were examined.

Results:
Significant differences existed between no DM and IDDM groups in the younger tertile only. Adjusting for threshold at 3 kHz had minimal effect. Self-reported noise exposure was not related to ABR differences, but HbA1c and poor circulation were.

Conclusions:
IDDM is associated with an increased wave V latency, wave I-V interval, and reduced wave V amplitude among Veterans under 50 years. Results were related to several DM complications. Laryngoscope, 2009

from The Laryngoscope

Parents’ views on the quality of life of their children 2–3 years after cochlear implantation

Conclusions
Parents report that cochlear implants affect their children in a wide variety of ways that cannot be summarized by a single scale. A broader descriptive framework is required to capture their experiences adequately.

from the International Journal of Pediatric Otorhinolaryngology

Inner ear involvement in Behçet’s disease

Conclusion
Even having hearing levels within normal limits in speech frequencies, increased hearing thresholds in high frequencies and decreased signal–noise ratios (SNR) in distortion product otoacoustic emission (DPOAE) indicate a cochlear involvement in patients with BD.

from Auris Nasus Larynx

Education, Occupation, Noise Exposure History and the 10-yr Cumulative Incidence of Hearing Impairment in Older Adults

The purpose of this study was to determine the 10-yr cumulative incidence of hearing impairment and associations of education, occupation and noise exposure history with the incidence of hearing impairment in a population-based cohort study of 3753 adults ages 48-92 years at the baseline examinations during 1993-1995 in Beaver Dam, WI. Hearing thresholds were measured at baseline, 2.5 yr, 5 yr, and 10-yr follow-up examinations. Hearing impairment was defined as a pure-tone average (PTA) > 25 dB HL at 500, 1000, 2000, and 4000 Hz. Demographic characteristics and occupational histories were obtained by questionnaire. The 10-yr cumulative incidence of hearing impairment was 37.2%. Age (5 yr; Hazard Ratio (HR)=1.81), sex (M v W; HR=2.29), occupation based on longest held job (Production/Operations/Farming vs others; HR=1.34), marital status (unmarried vs married; HR=1.29) and education (<16 vs 16+ yrs; HR=1.40) were associated with the 10 yr incidence. History of noisy jobs was not associated with the 10-yr incidence of hearing impairment. The risk of hearing impairment was high, with women experiencing a slightly later onset. Markers of socioeconomic status were associated with hearing impairment, suggesting that hearing impairment in older adults may be associated with modifiable lifestyle and environmental factors, and therefore, at least partially preventable.

from Hearing Research

Chromosome imbalances in syndromic hearing loss

The cause of hearing impairment has not been elucidated in a large proportion of patients. We screened by 1-Mb array-based comparative genomic hybridization (aCGH) 29 individuals with syndromic hearing impairment whose clinical features were not typical of known disorders. Rare chromosomal copy number changes were detected in eight patients, four de novo imbalances and four inherited from a normal parent. The de novo alterations define candidate chromosome segments likely to harbor dosage-sensitive genes related to hearing impairment, namely 1q23.3–q25.2, 2q22q23, 6p25.3 and 11q13.2–q13.4. The rare imbalances also present in normal parents might be casually associated with hearing impairment, but its role as a predisposition gene remains a possibility. Our results show that syndromic deafness is frequently associated with chromosome microimbalances (14–27%), and the use of aCGH for defining disease etiology is recommended.

from Clinical Genetics

Hearing Assessment in Infants and Children: Recommendations Beyond Neonatal Screening

Congenital or acquired hearing loss in infants and children has been linked with lifelong deficits in speech and language acquisition, poor academic performance, personal-social maladjustments, and emotional difficulties. Identification of hearing loss through neonatal hearing screening, regular surveillance of developmental milestones, auditory skills, parental concerns, and middle-ear status and objective hearing screening of all infants and children at critical developmental stages can prevent or reduce many of these adverse consequences. This report promotes a proactive, consistent, and explicit process for the early identification of children with hearing loss in the medical home. An algorithm of the recommended approach has been developed to assist in the detection and documentation of, and intervention for, hearing loss.

from Pediatrics

Measures of Hearing Threshold and Temporal Processing across the Adult Lifespan

Psychophysical data on hearing sensitivity and various measures of supra-threshold auditory temporal processing are presented for large groups of young (18-35 y), middle-aged (40-55 y) and older (60-89 y) adults. Hearing thresholds were measured at 500, 1414 and 4000 Hz. Measures of temporal processing included gap-detection thresholds for bands of noise centered at 1000 and 3500 Hz, stimulus onset asynchronies for monaural and dichotic temporal-order identification for brief vowels, and stimulus onset/offset asynchronies for the monaural temporal masking of vowel identification. For all temporal-processing measures, the impact of high-frequency hearing loss in older adults was minimized by a combination of low-pass filtering the stimuli and use of high presentation levels. The performance of the older adults was worse than that of the young adults on all measures except gap-detection threshold at 1000 Hz. Middle-aged adults performed significantly worse than the young adults on measures of threshold sensitivity and three of the four measures of temporal-order identification, but not for any of the measures of temporal masking. Individual differences are also examined among a group of 124 older adults. Cognition and age were found to be significant predictors, although only 10-27% of the variance could be accounted for by these predictors.

from Hearing Research

Aging, Hearing Acuity, and the Attentional Costs of Effortful Listening

A dual-task interference paradigm was used to investigate the effect of perceptual effort on recall of spoken word lists by young and older adults with good hearing and with mild-to-moderate hearing loss. In addition to poorer recall accuracy, listeners with hearing loss, especially older adults, showed larger secondary task costs while recalling the word lists even though the stimuli were presented at a sound intensity that allowed correct word identification. Findings support the hypothesis that extra effort at the sensory–perceptual level attendant to hearing loss has negative consequences to downstream recall, an effect that may be further magnified with increased age.

from Psychology and Aging

Age dependence of otoacoustic emissions: the loss of amplitude is primarily caused by age-related hearing loss and not by aging alone

The amplitude of otoacoustic emissions (OAE) is known to decrease with increasing age, but it is still unclear whether this is due to aging alone or to age-related hearing loss. This study describes the exploration of a large database (5,142 patients from 0.4 to 89.8 years) collected in a routine clinical testing. Reliable pure tone audiograms, transitory evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) recordings were available from 5,424 ears without conductive loss, acute sudden deafness or retrocochlear disorder. From this database, group 1 with behavioral thresholds of 10 dB HL or better at all frequencies from 1 to 4 kHz and group 2 with age-accordant thresholds after ISO 7029 were formed. In both groups, the OAE amplitude decreased with increasing age, but in group 1, the effect was significant only for DPOAE recorded at 3 and 4 kHz. In group 2, the loss of amplitude was steeper and highly significant for TEOAE as well as DPOAE at all frequencies, but most pronounced at high frequencies. These findings support the hypothesis that the reduction of OAE amplitude with increasing age is primarily caused by age-linked hearing loss and not by aging alone.

from ORL -Journal for Oto-Rhino-Laryngology and Its Related Specialties

Middle Ear Implantable Hearing Devices: An Overview

Hearing loss affects approximately 30 million people in the United States. It has been estimated that only approximately 20% of people with hearing loss significant enough to warrant amplification actually seek assistance for amplification. A significant interest in middle ear implants has emerged over the years to facilitate patients who are noncompliant with conventional hearing aides, do not receive significant benefit from conventional aides, or are not candidates for cochlear implants. From the initial studies in the 1930s, the technology has greatly evolved over the years with a wide array of devices and mechanisms employed in the development of implantable middle ear hearing devices. Currently, these devices are generally available in two broad categories: partially or totally implantable using either piezoelectric or electromagnetic systems. The authors present an up-to-date overview of the major implantable middle ear devices. Although the current devices are largely in their infancy, indications for middle ear implants are ever evolving as promising studies show good results. The totally implantable devices provide the user freedom from the social and practical difficulties of using conventional amplification.

from Trends in Amplification

The Effects of Bilateral Electric and Bimodal Electric—Acoustic Stimulation on Language Development

There is no doubt that cochlear implants have improved the spoken language abilities of children with hearing loss, but delays persist. Consequently, it is imperative that new treatment options be explored. This study evaluated one aspect of treatment that might be modified, that having to do with bilateral implants and bimodal stimulation. A total of 58 children with at least one implant were tested at 42 months of age on four language measures spanning a continuum from basic to generative in nature. When children were grouped by the kind of stimulation they had at 42 months (one implant, bilateral implants, or bimodal stimulation), no differences across groups were observed. This was true even when groups were constrained to only children who had at least 12 months to acclimatize to their stimulation configuration. However, when children were grouped according to whether or not they had spent any time with bimodal stimulation (either consistently since their first implant or as an interlude to receiving a second) advantages were found for children who had some bimodal experience, but those advantages were restricted to language abilities that are generative in nature. Thus, previously reported benefits of simultaneous bilateral implantation early in a child’s life may not extend to generative language. In fact, children may benefit from a period of bimodal stimulation early in childhood because low-frequency speech signals provide prosody and serve as an aid in learning how to perceptually organize the signal that is received through a cochlear implant.

from Trends in Amplification

Improving the Quality of Early Hearing Detection and Intervention Services through Physician Outreach

Physicians and other health-care providers should play a central role in helping families of children with permanent hearing loss receive timely and appropriate screening, diagnostic, and early intervention services. Because the technology and procedures for ensuring timely and appropriate services for infants and young children with hearing loss have changed so dramatically over the past 15 years, many health-care providers are not well informed about the best ways to provide effective services. Audiologists can help to ensure that physicians and other health-care providers are better informed about the services needed by infants and young children with hearing loss. This article notes some of the areas where information and support is most needed and suggests resources and strategies for addressing these needs.

from Seminars in Hearing

Physician Outreach: Overview

Physicians are vital members of many research and clinical teams on which audiologists often play leadership roles. As primary care providers and gatekeepers to both medical and audiological services, physicians possess the influence and opportunity to encourage patients of all ages and their families to recognize, accept, and seek further testing and treatment for hearing and balance problems when they exist. It is critical that physicians who work with patients of all ages having audiological-related issues possess current knowledge of these topics so that they can make appropriate referrals to audiologists for further diagnosis and intervention. Unfortunately, many physicians’ busy schedules and attention to patients’ more pressing medical issues often prevent them from staying current with information and making referrals relating to audiology services. Audiologists and their professional organizations can assist their medical colleagues by providing them with physician informational outreach on these topics. However, before initiating outreach efforts, audiologists should be aware of factors that might hinder physicians from delivering these services as well as those that may impede audiologists from being able to provide them with information. It is important that any information supplied be evidence based and presented to physicians in ways that are respectful of their time limitations and in formats that they desire. Although audiologists provide services to patients in many hearing- and balance-related areas, the problems encountered and methods of delivering physician outreach should be similar. This special issue of Seminars in Hearing focuses on physician outreach provided by audiologists and uses examples from two main areas (i.e., infants with hearing loss identified by early hearing detection and intervention programs and elderly patients with hearing or balance problems). Early identification of and intervention for these health-care conditions should improve the health-related quality of life for patients and their families. The results of many of the studies provided in the articles of this special issue have revealed that physicians could benefit from having additional information about audiological-related issues. Time and resources are limited for audiologists as well as for physicians, and this article provides an overview of factors that audiologists should be aware of and consider before conducting physician outreach efforts.

from Seminars in Hearing