Detailed Analysis of Auditory Brainstem Responses in Patients with Noise-induced Tinnitus

The role of the auditory brainstem in tinnitus is questionable. This study aimed comprehensively to assess auditory brainstem responses (ABRs) in patients suffering from noise-induced tinnitus (NIT). ABRs were recorded from 13 chronic NIT patients (21 ears) and 11 (21 ears) age and hearing matched control subjects without tinnitus. ABRs were recorded with scalp electrodes placed ipsilateral and contralateral to the stimulated ear, and in three orthonormal differential configurations. The ABRs were analyzed as a function of time, frequency and voltage space. A significantly enhanced ipsilaterally recorded, time domain wave III amplitude was observed for the tinnitus patients. This finding was not confirmed by any of the other ABR measures, which were indistinguishable between subject groups. Although this may be a spurious result, it nonetheless may point to an alteration in the functioning of the putative wave III auditory brainstem generator, which deserves further study.     

Is it necessary to perform occupational audiometric testing at 6-months of employment?

IntroductionCurrent Brazilian legislation requires that all workers exposed to noise are to be given an audiogram upon hiring, after 6 months of employment (first periodic test), and annually after the first periodic test. In other countries, the regulations of hearing conservation programs do not include the requirement for audiometric testing at 6 months of employment, but only annually. There is no evidence that the periodicity adopted by Brazilian legislation is the most appropriate.ObjectiveThe present study aimed to evaluate the first 3 occupational audiometric tests of workers exposed to noise.MethodsHistorical cohort study with cross-sectional analysis. Participants were all male metallurgy workers aged up to 40 years. The first 3 audiograms of each worker were analyzed: pre-employment audiometric test, periodic audiometric test 1, and periodic audiometric test 2. For each worker, mean frequency thresholds were calculated at 3, 4, and 6 kHz in the left and right ears for each test. Statistical analysis was performed using the nonparametric Wilcoxon test.ResultsA total of 988 workers were included. There was a significant difference in auditory thresholds between the pre-employment test and the 2 subsequent periodic tests for the right and left ears. There was no significant difference between Test1 and Test2 in either ear.ConclusionGiven the lack of difference between the first 2 periodic tests, we believe that they could be merged into a single test, i.e., first periodic audiometric testing could be performed at 12 months of employment without compromising workers’ health.     

125名船队工作人员听力健康现状与分析

目的：通过分析船队工作人员的听力情况,了解相关人员听力损失及耳鸣现状,为进一步完善噪声防护提供依据。方法对噪声岗位97名、非噪声岗位28名工作人员行声导抗和纯音测听（0.25～8 kHz）检查,通过问卷调查工作人员的耳鸣情况。结果非噪声、噪声岗位人员的平均听阈分别为25.39±9.67 dB HL、31.85±10.20 dB HL,语言频率听阈分别为24.51±8.84 dB HL、30.63±10.28 dB HL,高频听阈分别为27.99±17.75 dB HL、34.73±16.97 dB HL,低频听阈为25.04±8.20 dB HL、33.97±10.16 dB HL。非噪声、噪声岗位人员的耳鸣发生率分别为10.71%和53.61%。结论船舶噪声不仅引起高频听力损失,低频听力也出现下降。噪声岗位人员的耳鸣发生率是非噪声岗位人员的4～5倍。     

Tinnitus with or without hearing loss: are its characteristics different?

The present study was carried out in order to analyze the clinical characteristics of tinnitus both in normal hearing subjects and in patients with hearing loss. The study considered 520 consecutive tinnitus sufferers. The following parameters were considered: age, sex, subjective disturbance caused by tinnitus, subjective judgment of tinnitus intensity, tinnitus laterality, tinnitus duration, tinnitus measurements, normal hearing or associated hearing loss. Among the patients considered, 223 have normal hearing while 297 have a hearing deficit. The hearing impairment was found to be in most cases of sensorineural type. The subjective discomfort is higher in presence of hearing loss. Subjects with hearing loss needed significantly higher masking levels. No evident differences in the residual inhibition (RI) result between the two groups were found. The present study confirms that tinnitus is most frequently associated with hearing loss. The characteristics of tinnitus in normal hearing subjects, except for the subjective judgment of tinnitus intensity, the pitch and the RI, are significantly different for those observed in subjects with hearing loss. The association of tinnitus and hearing deficit seems to increase the perceived severity of the symptom.     

Acupuncture in the Management of Tinnitus: A Placebo-Controlled Study

The present study was performed on 20 patients randomly selected from a large group with noise-induced tinnitus in order to investigate the effect of acupuncture on their tinnitus. The patients were divided into two groups. One group first received classical Chinese needle acupuncture for 5 weeks, and the other was given a placebo procedure; after a 2-week interval, the procedures were reversed. A single-blind crossover design was used. Acupuncture was given by a Chinese otolaryngologist around the ear as well as at distal points on the extremities. Placebo consisted of mock electrical stimulation via surface electrodes connected to a Chinese electro-acupuncture stimulator which delivered a weak sound and a light flash at a frequency of 2 Hz but no current to the surface electrodes. The effect was evaluated by the use of visual analogue scales. No significant difference between acupuncture and placebo was found in annoyance, awareness or loudness of the tinnitus. Many patients indicated a preference for acupuncture due to unspecific effects such as improved sleep, decreased muscle tension and improved blood circulation. It is concluded that acupuncture has no specific alleviating effect on noise-induced tinnitus.     

Auditory frequency selectivity and tinnitus

Summary In the majority of cases tinnitus has a high pitch and can be matched rather precisely to an objective high frequency sound. However, it is well known that tinnitus can be masked by different tones without any frequency selectivity. We wondered whether objective tones matched to tinnitus would show a more significant deterioration of frequency selectivity than could be expected from any associated hearing loss. Psychoacoustic tuning curves were obtained using simultaneous pure-tone masking and revealed a broadening of frequency selectivity. In cases of comparable bilateral hearing losses with unilateral tinnitus, the broadening associated with the tinnitus was particularly conspicuous. This broadening strongly suggests that tinnitus originates in the cochlea, although some involvement of central pathways may also occur. Tinnitus-induced broadening of frequency selectivity as a possible sign of cochlear origin deserves further consideration in future studies.Presented at the First European Congress of Oto-Rhino-Laryngology and Cervico-Facial Surgery, Paris, 26–29 September 1988     

某部队官兵个体噪声暴露水平的测量与分析

目的：调查某坑道施工部队作业官兵的个体噪声暴露水平及超标人群工种的分布。方法按照部队施工情况,将官兵分为9个工种,使用个人声暴露计分别测量该部队官兵8小时等效声级（LAeq.8h）,按照《军事作业噪声容许限值及测量》（GJB 50A-2011）标准评价官兵噪声暴露水平是否超标。结果此坑道官兵的LAeq.8h波动在76.5～109.2 dB（A）,平均值88.90 dB（A）,其中台车操作手、破碎机操作手、强噪声工（暴露于各种机械噪声）、卡车操作手、装载机操作手、挖掘机操作手、喷杆工、装料工、弱噪声工（不常暴露于各种机械噪声环境）的LAeq.8h的平均值分别为103.37、88.97、91.00、85.45、90.32、89.72、86.53、81.60、83.10 dB（A）。结论除了弱噪声、装料人员,其他工种均已超过军事作业噪声容许限值85 dB（A）。在此坑道施工的官兵应加强噪声防护,以避免噪声性耳聋发生。     

Characteristics of tinnitus with or without hearing loss: Clinical observations in Sicilian tinnitus patients

Objective

To analyze the clinical characteristics of tinnitus both in normal hearing subjects and in patients with hearing loss.

Methods

The study considered 312 tinnitus sufferers, 176 males and 136 females, ranging from 21 to 83 years of age, who were referred to the Audiology Section of the Department of Bio-technology of Palermo University. The following parameters were considered: age, sex, hearing threshold, tinnitus laterality, tinnitus duration, tinnitus measurements and subjective disturbance caused by tinnitus. The sample was divided into two groups: Group 1 (G1) subjects with normal hearing; Group 2 (G2) subjects with hearing loss.

Results

Among the patients considered, 115 have normal hearing while 197 have a hearing deficit. There is a slight predominance of males respect to females that is more evidenced in G2 (61.42% of males vs. 38.58% of females). The highest percentage of tinnitus results in the decades 41–50 for G1 and >70 for G2 with a statistically significant difference between the two groups (P < 0.0001).The hearing impairment results in most cases of sensorineural type (74.62%) and limited to the high frequencies (58.50%), moreover the 72.10% of the patients with SNHL had a high-pitched tinnitus while the 88.37% of the patients high-frequency sensorineural hearing loss had a high-pitched tinnitus (P < 0.0001). As for the subjective discomfort, the catastrophic category resulted most representative among subjects with normal hearing with a statistically significant difference between the two groups but no significant correlation was found between the level of tinnitus intensity and the tinnitus annoyance confirming the possibility that tinnitus discomfort is elicited by a certain degree of psychological distress as anxiety, depression, irritability and phobias that do not allow the phenomenon of the ‘habituation’.

Conclusion

This work, according to literature data, suggests that the hearing status and the elderly represent the principal tinnitus related factors; moreover tinnitus characteristics differ in the two groups for tinnitus pitch. There is, in fact, a statistically significant association between high-pitched tinnitus and high-frequency SNHL suggesting that the auditory pathway reorganization induced by hearing loss could be one of the main source of the tinnitus sensation.     

北京某社区老年人群听力水平分布情况及自我认知能力的调查研究*

目的全面了解老年人群中不同听力水平分布情况和老年人对听力的自我认知能力.方法通过问卷调查获得老年人群听力水平自我评估结果,再通过纯音测听检测受试人群听力,评估老年人群对听力水平的自我认知能力.结果接受调查的516例老年人中,听力正常者181人(35.08%),轻度听力损失171人(33.14%),中度听力损失155人(30.04%),重度听力损失9人(1.74%);其中266人(51.55%)对自我的听力水平认知正确,171人(33.14%)自我认知听力水平高于实际水平,79人(15.31%)自我认知听力水平低于实际水平.结论在全身情况基本正常的老年人群中,50%以上的老年人能够正确认知自己的听力状况.     

A longitudinal study of changes in evoked otoacoustic emissions and pure-tone thresholds as measured in a hearing conservation program

Non-linear transient-evoked otoacoustic emissions (TEOAEs) at 74 dB pSPL, distortion-product otoacoustic emissions (DPOAEs) at 65/45 dB SPL and pure-tone audiometry were used to detect noise-induced, inner ear changes in a longitudinal study. Repeated-measures ANOVAs were made on the Noise (n=69) and Quiet (n=42) groups. The Noise group's hearing thresholds increased by 1.2 dB and DPOAE amplitude decreased by ?0.9 dB. For both groups, TEOAE amplitude decreased by approximately ?0.6 dB. Eight of 12 ears with permanent threshold shift (PTS) and 10 of 13 ears with temporary threshold shift (TTS) showed TEOAE decrements or low baseline TEOAE amplitudes. Fewer TTS and PTS ears also showed DPOAE decrements, and there was never a DPOAE decrement without a corresponding TEOAE decrement or low TEOAE baseline. Some TTS ears showed permanent emission decrements. Although otoacoustic emissions show promise in detecting noise-induced inner ear changes, it is premature to use them in hearing conservation programs.     

新疆不同民族耳鸣患者高频听力特点分析

目的探讨新疆不同民族以耳鸣为主要症状就诊患者的高频听力特征。方法对329例主观性耳鸣为主要症状的门诊就诊患者行病史和高频测听分析。结果各民族中汉族患者最多,女性多于男性,年龄分布以30～49岁为高峰,病程至少为半年以上,以无听力减退的耳鸣为主诉症状,纯音测听检查约1／3患者出现轻度感音神经性的听力减退。约2／3以上出现高频听力减退,其中以4kHz频率听力减退为主,且以50～70dB最多见。结论以耳鸣为主诉症状的患者当中大部分可测出高频听力的减退,为早期发现听力减退、防治耳聋等具有一定参考意义。     

Can a hearing education campaign for adolescents change their music listening behavior?

This study looked at whether a hearing education campaign would have behavioral effects on the music listening practices of high school students. A total of 1757 students participated in a hearing education campaign. Before the campaign and one year thereafter they completed a survey asking for: (1) average frequency of discotheque attendance, (2) average duration of stay in the discotheque, (3) use of earplugs in discotheques, (4) frequency of regeneration breaks while at a discotheque, and (5) mean time per week spent listening to music through headphones. On questions (2), (3) and (5) no relevant post-campaign changes were reported. On question (1) students' answers indicated that the frequency of discotheque attendance had even increased after the campaign. The only change in keeping with the purpose of the campaign was an increase in the number of regeneration breaks when at a discotheque. The effect of hearing education campaigns on music listening behavior is questioned. Additional efforts are suggested to encourage adolescents to adopt protective behaviors.     

Hyperactivity in the dorsal cochlear nucleus after intense sound exposure and its resemblance to tone-evoked activity: a physiological model for tinnitus

Intense tone exposure induces increased spontaneous activity (hyperactivity) in the dorsal cochlear nucleus (DCN) of hamsters. This increase may represent an important neural correlate of noise-induced tinnitus, a condition in which sound, typically of very high pitch, is perceived in the absence of a corresponding acoustic stimulus. Since high pitch sounds are thought to be represented in central auditory structures by the place of activation across the tonotopic array; it is therefore possible that the high pitch of noise-induced tinnitus occurs because intense sound exposure induces a tonotopic distribution of chronic hyperactivity in the DCN similar to that normally evoked only under conditions of high frequency stimulation. To investigate this possibility we compared this tone-induced hyperactivity with the activity evoked in normal animals by presentation of a tone. This comparison revealed that the activity in the DCN of animals which had been exposed to an intense 10 kHz tone 1 month previously showed a striking similarity to the activity in the DCN of normal animals during presentation of low to moderate level tonal stimuli of the same frequency. In both test conditions similar patterns were seen in the topographic distribution of the increased activity along the tonotopic axis. The magnitude of hyperactivity in exposed animals was similar to the evoked activity in the normal DCN responding to a stimulus at a level of 20 dB SL. These results suggest that the altered DCN following intense tone exposure behaves physiologically as though it is responding to a tone in the absence of a corresponding acoustic stimulus. The relevance of these findings to noise-induced tinnitus and their implications for understanding its underlying mechanisms are discussed.     

The clinical value of a thorough diagnostic evaluation for neurotologic complaints

Purpose

Determine the clinical efficacy of comprehensive neurotologic testing in patients presenting with complaints of hearing loss, tinnitus and/or dizziness.

Protective effect of a purified polyphenolic extract from Ecklonia cava against noise-induced hearing loss: Prevention of temporary threshold shift

ObjectiveNoise is one of the most common causes of hearing loss. Approximately 16% of American teenagers (12–19 years) have hearing loss caused by loud noise. The implication of noise-induced hearing loss (NIHL) in teenagers has received increasing attention. Although temporary threshold shift (TTS), a type of NIHL, is a transient hearing loss, it can accelerate age-related hearing loss. Reactive oxygen species are a primary cause of TTS. As the polyphenols from Ecklonia cava are known to have potent antioxidant effects, we investigated the protective effects of a purified polyphenolic extract of Ecklonia cava (PPEE) against TTS in mice.MethodsThe radical-scavenging activity of PPEE was evaluated using the 1,1-diphenyl-2-picrylhydrazyl assay. The PPEE + Noise and Saline + Noise groups were administered intraperitoneal PPEE (100 mg/kg) and saline, respectively, for 5 days before exposure to noise at 100 dB SPL for 60 min. Hearing ability was assessed following noise exposure using auditory brainstem responses and distortion product otoacoustic emissions.ResultsPPEE exhibited significant radical scavenging activity. The ABR threshold shifts 1 day after exposure to noise at 16 kHz and 1, 7, and 14 days after exposure to noise at 32 kHz, were significantly less in the PPEE + Noise than in the Saline + Noise group. One day after noise exposure, mice in the PPEE + Noise group showed a significant degree of protection in relation to their DPOAE level at f2, 17, and 28 kHz.ConclusionsThese findings suggest that PPEE may be a potential preventive agent against TTS. In addition, as a food ingredient approved by the United States Food and Drug Administration, PPEE may be administered to those who are exposed to noise inevitably with little likelihood of adverse effects, thereby contributing to the prevention of TTS.     

152^mm加农炮对听器损伤的调查

对参加实战的××式１５２ｍｍ加农炮兵撤出战斗后４个月的４７名９４耳进行了听器损伤的调查，结果表明耳聋症状发病率为２４．５％（以耳计，下同）；耳鸣发病率为１９．２％，多为低音调间歇性耳鸣。鼓膜内陷发病率为６６．０％。ＰＴＡ有改变者为１２．８％，高频听力损失（ＨＦ）为３６．２％。且以６０００Ｈｚ受损最明显，占受损耳的８７．０％。分析了４７名１５２ｍｍ加农炮兵听器损伤较轻的原因主要是发射炮弹时个人对耳的防护较好。     

The Increase in Prevalence of High Frequency Hearing Impairment Among College Students

There are numerous intense sounds in the environment to which regularity. To assess the effect of such noise exposure upon the hearing of persons under 21, a 2-part study was conducted. In the Fall of 1968, 2 769 Freshman entering the University of Tennessee were given a modified screening test for hearing. The failure level was established to be 15 dB (ISO, 1964 standard). If a student failed at any frequency, his threshold for hearing was measured for that frequency and recorded on a printed form. It was found that 4.6% of the students failed to respond to a 2 000 Hz stimulus. Failure levels were found to be 6.8, 10.5 and 29.4% for 3 000, 4 000 and 6 000 Hz, respectively. The procedure was repeated in testing 1 410 students in the Fall of 1969. It was discovered, however, that the prevalence of high frequency hearing impairment rose dramatically in this group. Failure rates were found to be 6.3, 13, 14.3 and 54.9% for the 2 000, 3 000, 4 000 and 6 000 Hz signals, respectively. Of the students tested, 7.4% had a hearing threshold of 40 dB or greater for the 6 000 Hz signal. Additional data are presented which indicate that the occurrence of measurable high frequency hearing impairment in young persons is tangible evidence of the toll being exacted by high intensity recreational and environmental sounds. The results of these studies are related to previous incidence studies and to histologic evidence of sensory cell damage observed in laboratory experiments.     

Auditory localization and its clinical applications

Factors of significance in the localization of sound are considered. The ability of hearing-impaired subjects to localize noise in the horizontal plane was examined with and without hearing aids, and also compared with the results for normally hearing subjects. The directional hearing was not found to be improved by the hearing aids used. The ability to localize sound has been used by several investigators as a diagnostic tool: poor directional hearing may be expected in patients with lesions of the cochlear nerve or the pontine region. However, other factors are also of significance and may impair the localization of sound. These problems are discussed.     

Audiometric testing and hearing protection training through multimedia technology

The purpose of this paper is to present the development process of a computer-based audiometric testing and tailored intervention program, and assess its feasibility by obtaining users’ feedback. The program was implemented for 397 operating engineers at their union training center, and its feasibility was evaluated by obtaining quantitative and qualitative feedback from the participants through a survey and focus group. Over 96% of the participants indicated they liked receiving a hearing test by computer; the computer-based test worked smoothly; and the computer-based training was well organized, effective and held their interests. Almost all (more than 99%) said they would recommend this program to other workers. This project is considered as one of the first ones incorporating multimedia computer technology with self-administered audiometric testing and tailored training. Participants’ favorable feedback strongly supported the continued utilization of this approach for designing and developing health screening and intervention to promote healthy behaviors.