Formal auditory training in adult hearing aid users

INTRODUCTION

Individuals with sensorineural hearing loss are often able to regain some lost auditory function with the help of hearing aids. However, hearing aids are not able to overcome auditory distortions such as impaired frequency resolution and speech understanding in noisy environments. The coexistence of peripheral hearing loss and a central auditory deficit may contribute to patient dissatisfaction with amplification, even when audiological tests indicate nearly normal hearing thresholds.

OBJECTIVE

This study was designed to validate the effects of a formal auditory training program in adult hearing aid users with mild to moderate sensorineural hearing loss.

METHODS

Fourteen bilateral hearing aid users were divided into two groups: seven who received auditory training and seven who did not. The training program was designed to improve auditory closure, figure-to-ground for verbal and nonverbal sounds and temporal processing (frequency and duration of sounds). Pre- and post-training evaluations included measuring electrophysiological and behavioral auditory processing and administration of the Abbreviated Profile of Hearing Aid Benefit (APHAB) self-report scale.

RESULTS

The post-training evaluation of the experimental group demonstrated a statistically significant reduction in P3 latency, improved performance in some of the behavioral auditory processing tests and higher hearing aid benefit in noisy situations (p-value < 0,05). No changes were noted for the control group (p-value <0,05).

CONCLUSION

The results demonstrated that auditory training in adult hearing aid users can lead to a reduction in P3 latency, improvements in sound localization, memory for nonverbal sounds in sequence, auditory closure, figure-to-ground for verbal sounds and greater benefits in reverberant and noisy environments.     

Exploring the perceptual characteristics of voice-hallucinations in deaf people

Introduction. Previous research has not taken account of the possibility that deaf people will show greater heterogeneity in how they experience voice-hallucinations due to individual differences in experience with language and residual hearing. This study aims to explore how deaf participants perceive voice-hallucinations and whether the perceptual characteristics reported reflect individual experience with language and sensory input.

Method. A statement-sorting task generated data about perceptual characteristics of voice-hallucinations for exploratory factor analysis. The sample included 27 deaf participants with experience of voice-hallucinations, and a range of hearing loss and language backgrounds.

Results. Perceptual characteristics of voice-hallucinations map closely onto individual auditory experience. People born profoundly deaf loaded onto nonauditory factors. Deaf people with experience of hearing speech, through residual hearing, hearing aids, or predeafness experience, reported auditory features or uncertainty about mode of perception.

Conclusions. This is the first study to systematically explore voice-hallucinations in deaf people and to advance a model of subvocal articulation to account for such counterintuitive phenomena.     

Gene dose of apolipoprotein E and age-related hearing loss

Next to outer hair cell dysfunction, age-related hearing loss may be explained by apolipoprotein E (APOE) genotype. In the Leiden 85-plus Study, a population-based study, the participants were 85 years old. We measured hearing loss by pure-tone audiometry in 435 participants in relation to APOE. Results demonstrated that those with the APOE-ε4/ε4 genotype had the highest levels of hearing loss (n = 6; 56.1 dB), those with the APOE-ε3/ε4 or ε2/ε4 genotype (n = 89) had intermediate levels of hearing loss (51.0 dB), and those without the APOE-ε4 allele (n = 340) had the lowest levels of hearing loss (48.9 dB), p for trend = 0.02. Eighty percent of participants had hearing loss of 35 dB and more, that is, hearing impairment. The APOE-ε4 allele was associated with a 2.0-fold increased risk of hearing impairment (confidence interval [CI 95%], 1.0-4.0), compared with those without the APOE-ε4 allele. The risk for hearing impairment in subjects with the APOE-ε4 allele remained similar after adjustment for cardiovascular disease, stroke, and cognitive impairment. Our results suggest that the APOE-ε4 allele contributes to age-related hearing loss.     

A health policy for hearing impairment in older Australians: what should it include?

Background

As in all western countries, Australia's older population experiences high levels of hearing impairment coupled with relatively low levels of hearing device usage. Poor hearing diminishes the quality of life of affected individuals and their families. This paper discusses how to improve Australian hearing health policies in order to better combat this impairment amongst older Australians.

Method

We searched the databases Medline, Meditext and Web of Science to find articles that discussed strategies and innovations to assist the hearing health of older people, and related this material to observations made during the Blue Mountains Hearing Study in NSW between 1997 and 2003.

Results and Discussion

The literature search identified five areas for inclusion in a comprehensive hearing health policy in Australia. These are: early intervention; addressing of hearing aid expense; the use of assisted listening devices; hearing rehabilitation, and; screening and education. Further research in Australia is critical if we are to develop a strong approach to the increasing prevalence of age-related hearing loss.

Conclusion

Australia needs to act now to address hearing impairment as it is a major cause of disability in those aged 55 and over. Federal and State governments should collaborate to construct a comprehensive hearing health policy that tackles poor levels of hearing health through early intervention, addressing hearing aid expense, encouraging the use of assisted listening devices, rehabilitation, screening and education. A good start would be to declare age related hearing impairment as a National Health Priority Area.

     

Prevalence of hearing problems, and use of hearing aids among a sample of elderly patients.

BACKGROUND. Deterioration of hearing with advancing age is well documented. However, the proportion of elderly people with hearing problems who wear hearing aids is low. AIM. The aim of this study was to assess the prevalence of hearing disability in a group of elderly patients in hospital and to determine their attitudes to hearing difficulties and the wearing of hearing aids. METHOD. A random sample of patients who were convalescing were interviewed. A detailed questionnaire was administered to patients regarding their hearing difficulties. RESULTS. A total of 79 patients were recruited. Twenty two patients were excluded because of low mental test scores, hence 57 patients (72%) were eligible for inclusion into the study. Thirty eight patients were women (mean age 81 years) and 19 were men (mean age 79 years). Thirty patients (53%) reported difficulties with their hearing, of whom 12 had hearing aids. Seventeen patients had consulted their general practitioner about their difficulties, 15 of whom had been referred for audiological examination. Thirteen patients chose not to consult about their hearing problems, to 'suffer in silence'. Of the 12 patients with hearing aids three reported discomfort or pain and five reported problems such as an ill-fitting hearing aid and excessive amplification. Six patients said they wore their hearing aid for less than four hours a day. CONCLUSION. Almost all patients consulting their general practitioner with hearing problems were referred for audiological examination but subsequent follow up, especially of problems with hearing aids, was poor. Better health education and case finding is indicated and patients with hearing aids must be questioned specifically about problems when they consult health professionals. Proper assessment, screening and follow up has implications for resources and training, especially of practice nurses.     

Auditory functions in children at schools for the deaf

OBJECTIVE: To evaluate auditory functions in children at schools for the deaf in Turkey. DESIGN: A total of 218 children who were attending the school for deaf children were involved in the study. Familial and medical histories were obtained, and otoscopic examinations were performed. Immittance audiometry, acoustic reflex testing, pure tone audiometry, otoacoustic emission and auditory brain stem response tests were performed. RESULTS: The mean age of identification of hearing loss was 48 months. Impacted wax was the most common otoscopic finding that was seen in 49 (22.47%) of children. Nontype-A tympanograms were found in 18 (8.25%) of children. One-hundred-eighty-nine (86.69%) children had profound hearing loss, and 29 (10.3%) had severe hearing loss on pure tone audiometry. On auditory brain stem response testing, 192 (88.07%) children had profound hearing loss, and 26 (11.41%) had severe hearing loss. Only one child had auditory neuropathy/dys-synchrony, as his otoacoustic emission results were normal without synchronous auditory brain stem responses. The hearing threshold levels were found >105 dB in 28 children only with pure tone audiometry. CONCLUSION: Early auditory screening is necessary to identify the children at risk. All hearing disorders cannot be detected by subjective or objective audiometric tests only. Pure tone audiometry still has a role in determining hearing threshold levels. The audiological research directions should be directed towards routine pure tone audiometry, otoacoustic emission and auditory brain stem response assessment for all hearing impaired children to enable an successful treatment.     

Referrals to a hearing aid clinic: scope for improvement.

This study followed on from a recent national publicity campaign aiming to get earlier provision of hearing aids for elderly people, improve both patient and general practitioner awareness of hearing impairments and increase knowledge of alternative environmental aids among sufferers. The study intended to examine present patterns of patient presentation and general practitioner management within a major Scottish city. A random sample of patients over the age of 55 years referred to a hearing aid clinic were questioned on the nature of their hearing difficulty. Patients who attended their general practitioner at the suggestion of a relative were less likely to be referred at their initial visit and significantly less likely to have had their ears syringed than those who were self-motivated. Respondents had little knowledge of alternatives to hearing aids, although these are relevant to the disability experienced by the majority of these subjects.     

Prevalence of hearing loss among people aged 65 years and over: screening and hearing aid provision.

The aim of this study was to assess the prevalence of hearing loss among people aged 65 years and over and to offer hearing aids where necessary. The study was carried out in a large health centre practice in Birmingham with a computerized record system. All patients aged 65 years, and a 20% random sample of patients aged 66 years and over were invited for interview. They were questioned about hearing loss and examined audiometrically. All patients with a hearing loss in the better ear of 35 decibels or more over the speech frequencies (0.5-4 kHz) were offered a hearing aid. A total of 322 patients attended (72% of those invited) and of these 34 patients already had a hearing aid. A further 142 patients were identified for whom an aid was recommended and 69 of these accepted. The acceptance rate was higher among men than women (57% compared with 43%). Sixty one patients (19% of those screened) had an asymmetrical hearing loss and of these 24 required consultant assessment; none had serious underlying pathology. There is a large unmet need for hearing aid provision. Simple audiometric assessment in health centres provides an opportunity to meet this need.     

Computer skills and internet use in adults aged 50-74 years: influence of hearing difficulties

Background

The use of personal computers (PCs) and the Internet to provide health care information and interventions has increased substantially over the past decade. Yet the effectiveness of such an approach is highly dependent upon whether the target population has both access and the skill set required to use this technology. This is particularly relevant in the delivery of hearing health care because most people with hearing loss are over 50 years (average age for initial hearing aid fitting is 74 years). Although PC skill and Internet use by demographic factors have been examined previously, data do not currently exist that examine the effects of hearing difficulties on PC skill or Internet use in older adults.

Objective

To explore the effect that hearing difficulty has on PC skill and Internet use in an opportunistic sample of adults aged 50-74 years.

Methods

Postal questionnaires about hearing difficulty, PC skill, and Internet use (n=3629) were distributed to adults aged 50-74 years through three family physician practices in Nottingham, United Kingdom. A subsample of 84 respondents completed a second detailed questionnaire on confidence in using a keyboard, mouse, and track pad. Summed scores were termed the “PC confidence index.” The PC confidence index was used to verify the PC skill categories in the postal questionnaire (ie, never used a computer, beginner, and competent).

Results

The postal questionnaire response rate was 36.78% (1298/3529) and 95.15% (1235/1298) of these contained complete information. There was a significant between-category difference for PC skill by PC confidence index (P<.001), thus verifying the three-category PC skill scale. PC and Internet use was greater in the younger respondents (50-62 years) than in the older respondents (63-74 years). The younger group’s PC and Internet use was 81.0% and 60.9%, respectively; the older group’s PC and Internet use was 54.0% and 29.8%, respectively. Those with slight hearing difficulties in the older group had significantly greater odds of PC use compared to those with no hearing difficulties (odds ratio [OR]=1.57, 95% confidence interval [CI] 1.06-2.30, P=.02). Those with moderate+ hearing difficulties had lower odds of PC use compared with those with no hearing difficulties, both overall (OR=0.58, 95% CI 0.39-0.87, P=.008) and in the younger group (OR=0.49, 95% CI 0.26-0.86, P=.008). Similar results were demonstrated for Internet use by age group (older: OR=1.57, 95% CI 0.99-2.47, P=.05; younger: OR=0.32, 95% CI 0.16-0.62, P=.001).

Conclusions

Hearing health care is of particular relevance to older adults because of the prevalence of age-related hearing loss. Our data show that older adults experiencing slight hearing difficulty have increased odds of greater PC skill and Internet use than those reporting no difficulty. These findings suggest that PC and Internet delivery of hearing screening, information, and intervention is feasible for people between 50-74 years who have hearing loss, but who would not typically present to an audiologist.     

Source Localisation of Visual Evoked Potentials in Congenitally Deaf Individuals

Previous studies have suggested that individuals deprived of auditory input can compensate with specific superior abilities in the remaining sensory modalities. To better understand the neural basis of deafness-induced changes, the present study used electroencephalography to examine visual functions and cross-modal reorganization of the auditory cortex in deaf individuals. Congenitally deaf participants and hearing controls were presented with reversing chequerboard stimuli that were systematically modulated in luminance ratio. The two groups of participants showed similar modulation of visual evoked potential (VEP) amplitudes (N85, P110) and latencies (P110) as a function of luminance ratio. Analysis of VEPs revealed faster neural processing in deaf participants compared with hearing controls at early stages of cortical visual processing (N85). Deaf participants also showed higher amplitudes (P110) than hearing participants. In contrast to our expectations, the results from VEP source analysis revealed no clear evidence for cross-modal reorganization in the auditory cortex of deaf participants. However, deaf participants tended to show higher activation in posterior parietal cortex (PPC). Moreover, modulation of PPC responses as a function of luminance was also stronger in deaf than in hearing participants. Taken together, these findings are an indication of more efficient neural processing of visual information in the deaf, which may relate to functional changes, in particular in multisensory parietal cortex, as a consequence of early auditory deprivation.     

电子耳蜗言语训练及发音模拟系统

听力障碍患者可根据听力障碍程度选择佩戴助听器或植入电子耳蜗，其中重度耳聋患者需要植入电子耳蜗以恢复听力感知能力。电子耳蜗手术植入后，患者仍需要大量的言语康复训练，以适应电子耳蜗和日常言语交流。目前，训练的主要方式是人工训练，不利于提高听力康复训练的效率。本研究开发了一套基于电子耳蜗常用言语处理策略的言语训练及发音模拟系统。该系统可用于语音信号的采集，并进一步将采集到的信号转换成特定的言语处理策略。它可以帮助医生对患者进行听力训练，也可以用于开发新的言语处理策略和算法评估，该系统采集和合成的康复训练信号能准确地反映电子耳蜗言语处理策略的特点，GUI界面简单易用，便于在临床推广应用。     

Hearing and Speech Perception for People With Hearing Loss Using Personal Sound Amplification Products

BackgroundHearing loss (HL) is the most common chronic disease and has been linked to negative health outcomes. Hearing aids (HAs) are regarded as the gold standard for HL management, however, the adoption rate of HAs is relatively low for various reasons. With this background, hearing devices, such as personal sound amplification products (PSAPs) received significant attention as an alternative to conventional HAs. This study aimed to evaluate the clinical efficacy of PSAPs in patients with mild to moderately severe HL.MethodsNineteen patients with mild hearing loss (MHL), 23 with moderate hearing loss (MDHL), and 15 with moderately severe hearing loss (MSHL) participated in the study. Electroacoustic analysis, simulated real-ear measurements (REMs), and three clinical evaluations were implemented.ResultsAll devices satisfied the electroacoustic tolerances. All devices provided sufficient gain for MHL and MDHL audiograms. However, in MSHL audiogram, the gains of PSAPs were insufficient, especially for high frequencies. In terms of clinical evaluations, sound-field audiometry showed significant improvements between aided and unaided thresholds in all groups for all devices (P < 0.001). Significant improvements of word recognition scores were only shown for HAs between aided and unaided conditions. The Korean version of the Hearing In Noise Test did not show any consistent findings for all devices and groups.ConclusionCertain PSAPs are beneficial for improving hearing and speech perception in patients with HL. Well-chosen PSAPs could be an alternative hearing rehabilitation option for these patients.     

Cortical Processing of Level Cues for Spatial Hearing is Impaired in Children with Prelingual Deafness Despite Early Bilateral Access to Sound

Bilateral cochlear implantation aims to restore binaural hearing, important for spatial hearing, to children who are deaf. Improvements over unilateral implant use are attributed largely to the detection of interaural level differences (ILDs) but emerging evidence of impaired sound localization and binaural fusion suggest that these binaural cues are abnormally coded by the auditory system. We used multichannel electroencephalography (EEG) to assess cortical responses to ILDs in two groups: 13 children who received early bilateral cochlear implants (CIs) simultaneously, known to protect the developing auditory cortices from unilaterally driven reorganization, and 15 age matched peers with normal hearing. EEG source analyses indicated a dominance of right auditory cortex in both groups. Expected reductions in activity to ipsilaterally weighted ILDs were evident in the right hemisphere of children with normal hearing. By contrast, cortical activity in children with CIs showed: (1) limited ILD sensitivity in either cortical hemisphere, (2) limited correlation with reliable behavioral right-left lateralization of ILDs (in 10/12 CI users), and (3) deficits in parieto-occipital areas and the cerebellum. Thus, expected cortical ILD coding develops with normal hearing but is affected by developmental deafness despite early and simultaneous bilateral implantation. Findings suggest that impoverished fidelity of ILDs in independently functioning CIs may be impeding development of cortical ILD sensitivity in children who are deaf but do not altogether limit benefits of listening with bilateral CIs. Future efforts to provide consistent/accurate ILDs through auditory prostheses including CIs could improve binaural hearing for children with hearing loss.     

Audiological follow-up of 24 patients affected by Williams syndrome

Williams syndrome is a neurodevelopmental disorder associated with cardiovascular problems, facial abnormalities and several behavioural and neurological disabilities. It is also characterized by some typical audiological features including abnormal sensitivity to sounds, cochlear impairment related to the outer hair cells of the basal turn of the cochlea, and sensorineural or mixed hearing loss, predominantly in the high frequency range. The aim of this report is to describe a follow-up study of auditory function in a cohort of children affected by this syndrome. 24 patients, aged 5–14 years, were tested by means of air/bone conduction pure-tone audiometry, immittance test and transient evoked otoacoustic emissions. They were evaluated again 5 years after the first assessment, and 10 of them underwent a second follow-up examination after a further 5 years. The audiometric results showed hearing loss, defined by a pure tone average >15 dB HL, in 12.5% of the participants. The incidence of hearing loss did not change over the 5-year period and increased to 30% in the patients who underwent the 10-year follow-up. Progressive sensorineural hearing loss was detected in 20% of the patients. A remarkable finding of our study regarded sensorineural hearing impairment in the high frequency range, which increased significantly from 25% to 50% of the participants over the 5-year period. The increase became even more significant in the group of patients who underwent the 10-year follow-up, by which time the majority of them (80%) had developed sensorineural hearing loss. Otoacoustic emissions were found to be absent in a high percentage of patients, thus confirming the cochlear fragility of individuals with Williams syndrome. Our study verified that most of the young Williams syndrome patients had normal hearing sensitivity within the low-middle frequency range, but showed a weakness regarding the high frequencies, the threshold of which worsened significantly over time in most patients.     

Hearing handicap, rather than measured hearing impairment, predicts poorer quality of life over 10 years in older adults

Background

We aimed to determine the prospective association between measured hearing impairment, self-reported hearing handicap and hearing aid use with quality of life.

Study design

829 Blue Mountains Hearing Study participants (≥55 years) were examined between 1997–1999 and 2007–2009. The shortened version of the hearing handicap inventory was administered. Hearing levels were measured using pure-tone audiometry. Quality of life was assessed using the 36-Item Short-Form Survey (SF-36); higher scores reflect better quality of life.

Results

Hearing impairment at baseline compared with no impairment was associated with lower mean SF-36 mental composite score 10 years later (multivariable-adjusted p = 0.03). Physical composite score and mean scores for seven of the eight SF-36 domains after 10-year follow-up were significantly lower among participants who self-reported hearing handicap at baseline. Differences in the adjusted means between participants with and without hearing handicap ranged from 2.7 (physical composite score) to 10.4 units (‘role limitations due to physical problems’ domain). Individuals who developed incident hearing impairment compared to those who did not, had adjusted mean scores 9.5- and 7.7-units lower in the ‘role limitation due to physical problems’, and ‘bodily pain’ domains, respectively, at the 10-year follow-up. Hearing aid users versus non-users at baseline showed a 1.82-point (p = 0.03) and 3.32-point (p = 0.01) increase in SF-36 mental composite score and mental health domain over the 10-year follow-up, respectively.

Conclusion

Older adults with self-perceived hearing handicap constitute a potential risk group for overall deterioration in quality of life, while hearing aid use could help improve the well-being of hearing impaired adults.     

新生儿及疑似听力障碍儿童听力筛查的病例分析

目的1.收取本地区新生儿听力障碍发病资料;2.分析听力筛查未通过的因素及临床听力学特征。方法选取2006年5月至2007年5月出生的286例新生儿,在出院前进行新生儿听力筛查;96例转诊至我科的疑似听力障碍患儿进行诊断性听力学检查。对未通过者进行声阻抗、耳声发射、听性脑干反应、听觉稳态诱发反应全面的综合检查以确定听力损失的性质和程度,给予相应干预措施。结果286例新生儿,其中初筛有40例（13.99%）未通过筛查,42天复筛DPOAE,最后有3例需行ABR检查,经过听力学初步评估发现2例（发病率为6.99‰）有听力损失,其中正常新生儿1例（发病率为3.94‰）,高危新生儿1例（发病率为31.25‰）并作相应诊断和干预;转诊疑似听力损失患儿96例,确认听力损失78例（81.25%）,其中轻度2例（2.5%）、中度7例（9.0%）、重度25例（32.1%）、极重度44例（56.4%）,发现确诊年龄在6个月～3岁范围内。结论3个月内早期诊断和6个月内早期干预是必要的,以便尽早发现患儿及时给予干预。推行新生儿及婴幼儿听力损失的早期筛查和干预,加强耳聋知识的宣传,提高家长的防聋治聋意识是非常必要的。     

A randomised controlled trial of screening for adult hearing loss during preventive health checks.

BACKGROUND: Prophylactic strategies to counter acquired hearing impairment may involve routine audiometric screening of asymptomatic working-age adults attending general practice for regular health checks. AIM: To evaluate the effect of adult hearing screening on subsequent noise exposure and hearing. DESIGN OF STUDY: A randomised controlled population-based study of health checks and health discussions in general practice. SETTING: The project was initiated in the district of Ebeltoft, Aarhus county, Denmark. METHOD: Intervention group participants' hearing thresholds were determined audiometrically at 0.5, 1, 2, 3, and 4 kHz in each ear. Participants were advised to get their ears checked if the average hearing loss exceeded 20 dB hearing level (dBHL) in either ear. Noise avoidance was emphasised when thresholds exceeded 25 dBHL bilaterally at 4 kHz. Follow-up included questionnaires and audiometry. RESULTS: Hearing loss was observed among 18.9% of the study sample at baseline. At the five-year follow-up we recorded no significant differences between the control and the intervention groups regarding subjective or objective hearing, or exposure to occupational noise. However, there was a tendency towards reduction in exposure to leisure noise among intervention participants (P = 0.045). Approximately 20% reported hearing problems; 16.5% reported tinnitus-related complaints; 0.8% used hearing aids; 35.0% reported frequent noise exposure; and occluding wax was suspected in 2.1%. CONCLUSION: Preventive health checks with audiometry did not significantly affect hearing, but leisure noise exposure tended to become less frequent. The poor effect may be ascribed to inadequate audiological counselling or a higher priority to other advice, e.g. on cardiovascular risk or lifestyle.     

What is the potential for context aware communication aids?

Abstract

Use of voice output communication aids (VOCAs) can be a very effective strategy to assist people with speech impairments in communicating. Despite this, people who use communication aids often express frustration with VOCAs—desiring devices that are simpler, quicker and more effective to use. Whilst it is not possible to resolve all these issues with technology, it is argued that significant progress can be made. The use of contextual information is one development that could improve the simplicity and effectiveness of communication aid design. Improving the effectiveness of communication aids, including through the use of context support, is a goal of the NIHR Devices for Dignity Assistive Technology Theme. This discussion paper examines the potential for creating ‘context aware’ communication aids. Three projects in which the authors have been involved are described to illustrate different approaches to the use of contextual information.     

Acute versus chronic acoustic deprivation: effects on auditory evoked potentials and seizures in mice.

C57BL/6J mice are not typically susceptible to audiogenic seizures, but temporary conductive hearing loss (via earplugging) can induce susceptibility in these subjects. The present study observed that a 40-dB hearing loss, beginning at 17 days postpartum, requires 2 days before it induces susceptibility to audiogenic seizures. When this hearing loss occurred only between 17 and 21 days postpartum, seizures were maximally severe 1-2 days after earplug removal. The peak-to-peak amplitudes of the auditory evoked potential (AEP) were also maximal at this same time. But mice deprived of acoustic input between ages 42-46 days exhibited equally large or even larger AEP amplitudes, while not exhibiting susceptibility to audiogenic seizures. Animals at this older age were shown to be capable of convulsing, in that chronic conductive loss from 17-42 days maintained susceptibility to audiogenic seizures. The acoustic deprivation produced both behavioral (audiogenic seizures) and neural (augmented AEP amplitudes) supersensensitivity to sound, but the former requires a critical period, whereas the latter does not. Some degree of residual hearing loss persisted at all ages for approximately 2 days after removal of the earplugs.     

Prevalence and characterization of hearing loss in workers exposed to industrial noise of the turbogenerated electric plant of a petrochemical industry

The purpose of the present study was to assess the impact of occupational exposure to noise and its relationship with other factors that can induce hearing loss in the electric plant workers of a petrochemical industry of the west of Venezuela. A cross-sectional study was conducted that included sonometry tests, carried out according to the established methodology by COVENIN rules, and the occupational medical evaluation and liminal tonal audiometrics test in 75 workers. The equivalent noise levels (Leq) was quantified in different workplaces. It was found out that most of the workers are exposed to high noise levels [>85 dB(A)] and during more time than the recommended. All workers use hearing protectors appropriately. The hearing loss prevalence in workers was 16.0%, there were not noise-induced hearing losses. The hearing threshold registered in the audiometrics test was diminished, but inside the normal threshold values. We diagnosed 12 cases of conductive hearing loss, all grade I; there were not sensorial or mixed hearing losses. There was not a relationship between the equivalent noise level and hearing loss. It is suggested the design and implantation of a program of auditory conservation to protect the health and security of the workers and to conduct a longitudinal study considering the findings of the present study as it basis.