Severity Of Noise-induced Hearing Loss Research Articles

Hearing Loss Due to Occupational Exposure: An Analysis of Cases at Lahore

Objective: To study the severity of noise-induced hearing loss and noise levels in the environment in occupationally exposed individuals at Pakistan air force base Lahore.
 Study Design: Prospective longitiginal study.
 Place and Duration of Study: Pakistan Air Force base Lahore Pakistan, from Dec 2019 to Jun 2020.
 Methodology: The noise levels and duration of exposure to loud noise were measured at various exposure points to define ways and means for future prevention.
 Results: Out of 3000 patients reporting to the ENT outpatient department for various problems, 33.3% had ear problems. Out of 1000, 750 had hearing loss with normal tympanic membranes. Among 750, 200 (26.6%) had conductive hearing loss, while 550 (73.3%) had sensorineural hearing loss. Out of 550, 70 (12.72%) were related to occupational exposure in service and 480 (87.2%) were due to various causes. Most patients reported from the security wing (40, 57.14%) being exposed to the loud noise of gunfire as a pulsed exposure, followed by patients in the telecommunication field (20, 28.57%) being exposed to persistent noise.
 Conclusion: Occupational exposure to loud noise in the workplace poses significant health issues, including an economic burden on an individual. NIHL related to occupational exposure to loud sounds is frequently reported worldwide. Education and prevention are two vital steps which can reduce the number of such cases significantly, thus preventing this lifelong disability, ensuring health and reducing the economic burden.

Correlation between duration of noise exposure and severity of hearing loss

Background and Objective: Noise pollution is one of the commonest occupational and environmental health hazard. The extent of damage to hair cells is determined by the intensity of noise to which a person is exposed, and the duration of noise exposure [1]. Prolonged exposure to high intensity noise >85dB(A) or more, for eight hours can lead to permanent hearing loss. This exposure can be reduced significantly by using simple ear protection devices. NIHL can be easily prevented through the use of simple and economical tools, but are not used by people due to different reasons.3Our study aimed at determining the relation between the duration of exposure to loud noise on the severity of noise-induced hearing loss. The subjects of our study were train drivers working in an extremely noisy environment for long hours, without using any ear protection tool. Materials and Method: This study involved 60 subjects, who were all train drivers. They were working in an extremely noisy environment for more than eight hours a day for more than ten years. The responses to brainstem evoked response audiometry were recorded and evaluated for severity of hearing loss. Result: 60% subjects reported positive for sensorineural deafness. 18.3% of the subjects were having mild degree of hearing loss, 23.3% were having moderate degree of hearing loss and 18.3% were having severe degree of hearing loss. Conclusion: It was found that the duration of exposure to noise has a positive correlation with the degree of severity of hearing loss (p

Functional BCL-2 rs2279115 Noncoding variant associated with noise-induced hearing loss in Chinese workers: a case-control study

Background: Noise-induced hearing loss (NIHL) is one of the most common form of severe sensorineural hearing impairment. Both environmental and genetic factors contribute to the occurrence and severity of NIHL.

Effects of Noise Exposure on the Vestibular System: A Systematic Review.

Despite our understanding of the impact of noise-induced damage to the auditory system, much less is known about the impact of noise exposure on the vestibular system. In this article, we review the anatomical, physiological, and functional evidence for noise-induced damage to peripheral and central vestibular structures. Morphological studies in several animal models have demonstrated cellular damage throughout the peripheral vestibular system and particularly in the otolith organs; however, there is a paucity of data on the effect of noise exposure on human vestibular end organs. Physiological studies have corroborated morphological studies by demonstrating disruption across vestibular pathways with otolith-mediated pathways impacted more than semicircular canal-mediated pathways. Similar to the temporary threshold shifts observed in the auditory system, physiological studies in animals have suggested a capacity for recovery following noise-induced vestibular damage. Human studies have demonstrated that diminished sacculo-collic responses are related to the severity of noise-induced hearing loss, and dose-dependent vestibular deficits following noise exposure have been corroborated in animal models. Further work is needed to better understand the physiological and functional consequences of noise-induced vestibular impairment in animals and humans.

Noise-induced hearing loss in bus and truck drivers in Mazandaran province, 2011

Background and purpose. Noise-induced hearing loss (NIHL) is among the most prevalent and preventable work-related disorders. This study was conducted to evaluate the prevalence and severity of NIHL in bus and truck drivers of Mazandaran province in north Iran. Materials and methods. In a cross-sectional descriptive study, 2283 drivers were examined clinically and para-clinically, including measuring their fasting blood sugar, triglyceride and cholesterol levels. All participants were evaluated for the air and bone thresholds of both ears. Twenty-three individuals were excluded from the study because of conductive hearing loss. Data from 2260 drivers were analyzed using SPSS version 18. Results. Of the drivers, 37.5% had hearing loss in the right ear and 41.8% of the drivers had hearing loss in the left ear in one or more frequencies of sound. Hearing loss was significantly more frequent in the left ear and in 6000 Hz followed by 4000 Hz. Conclusion. Our study showed that the prevalence and severity of NIHL is high in drivers of Mazandaran province. There was a correlation between hearing loss and age and driving work history. We recommend considering hearing conservation programs more seriously.

Noise-Induced Hearing Loss: Prevention is Possible

Background: In Denmark, the preventive measures against occupational noise-induced hearing loss (NIHL) were intensified in 1995. Apparently, no extant studies have attempted to document the effect of these measures. Objectives: This study aims to estimate the prevalence and severity of noise-induced hearing loss after 1995 and to explain the factors that influence the official statistics regarding hearing loss. Patients and Methods: Screening audiograms from 272 noise-exposed workers were studied in an attempt to distinguish between noiseinduced hearing loss (NIHL) and hearing loss resulting from other causes. The results were compared with deductions that could be made from official work environment statistics. Results: Calculations based on official work environment statistics show that the proportion of NIHL among the reported cases of hearing loss has decreased, so that the proportion of non-NIHL has increased. Further, the severity of occupational NIHL has decreased. Among the 272 tested persons, 88 (32%) presumably had NIHL. A combination of NIHL and hearing losses of other causes was found in 28 (10%), while 43 (16%) had a hearing loss that could not be NIHL. Normal hearing was found in 113 (42%). Overall, roughly, one third of the tested persons had NIHL, and among the 159 cases with hearing loss, a factor other than noise played a role. The measures against NIHL have had a positive effect. When, nevertheless, the annually reported number of cases continues to rise, it is because minimal NIHL cases and cases that are not NIHL are included in the statistics. The present study suggests that the non-NIHL group may amount to about 40 % of the reported cases. The official statistics should be refined to take this confounding aspect into account. Conclusions: Despite rising figures of reported occupational hearing loss, working NBII statistics show that the NIHL problem in the Danish work environment has, in fact, decreased. In our study, we found that roughly one third (around 100 cases) of the 272 screened persons presumably had NIHL, taking into account 88 probable cases (Column B) and 44 questionable ones (Column C + 16 ski slopes). About 45% of those who did not pass the screening had a hearing loss in which noise could be, at the most, a contributory factor. In 116 cases of probable or possible NIHL, the average hearing loss was only 33 dB, and in only 11 cases (9%) was the hearing loss considered severe enough to qualify for compensation. Our audiometric findings are, in all probability, valid for similar plants in this country and suggest that the noise problem is reasonably under control. This corroborates the deductions that can be made from the official statistics. It is evident, therefore, that NIHL incidence and severity can be reduced in countries that implement and enforce appropriate work environment legislation. However, documentation of the effect requires data storage and retrieval systems that can distinguish between NIHL and non-NIHL cases and are also able to grade the severity of NIHL.

Noise-Induced Hearing Loss in the Police Force.

BackgroundNoise-induced hearing loss (NIHL) is a major preventable occupational health problem with 250 million people worldwide known to have disabling impairment of moderate to greater severity. The aims of the study are to estimate the prevalence of NIHL in the police force; and study its association with age, sex, duration of service (years), smoking and alcohol habits, use of hearing protective devices, as well as preexisting chronic diseases.MethodsA cross-sectional study was conducted on 543 police personnel who had undergone periodic medical examination over a 12-month period. The diagnostic criteria for NIHL were (1) history of occupational noise exposure, (2) bilateral hearing loss, (3) hearing loss of ≥ 25 dBA at 4,000 Hz in two consecutive audiograms, and (4) no significant medical history affecting hearing. Severity of NIHL was based on the World Health Organization grading.ResultsMales (74.8%) made up the majority of the police force. The mean age for police personnel was 35.55 ± 9.57 years, and the mean duration of service was 14.75 ± 9.39 years. Compliance with the usage of hearing protective devices was seen in 64.4%. The prevalence of NIHL in this study population was 34.2%, with a higher prevalence in males (37.7%) than in females (23.9%). The study also showed strong associations between NIHL and male sex (odds ratio, 1.9; P < 0.05), and hypertension (odds ratio, 3.3; P < 0.001). Overall, 93% were found to have mild NIHL, 3.5% had moderate NIHL, and 3.5% had severe NIHL. No police personnel were found to have profound hearing loss.ConclusionThe prevalence of NIHL in this study is high compared to other similar studies among police personnel. This study shows that increasing age, male, presence of hypertension, diabetes, and longer duration of service are significant associated factors for NIHL. Preventative strategies include health surveillance, implementation of a hearing conservation program, and legislation.

Pure-tone audiometry and auditory brainstem responses in noise-induced deafness

Purpose: The objective of this study is to find the relationship between pure-tone audiometry results and the auditory brainstem response wave abnormalities. Subjects and Methods: The pure-tone audiometry (PTA) and auditory brainstem responses (ABRs) from 22 patients (44 ears) with diagnosed noise-induced permanent hearing loss were studied. Three indices of PTA were average thresholds of 0.5 kHz/, /1 kHz, and 2 kHz (PTA1); 2 kHz and 4 kHz (PTA2); and 4 kHz (PTA3) were subdivided into 3 thresholds of hearing. Their relationships with ABR results were analysed. The patterns of PTA from various groups of ABR wave patterns were studied. Results: In this study, the abnormal ABR wave patterns were detected in 72.7% of the ears. The ears with prolonged ABR wave latency, absent early waves, prolong interpeak wave I–V latency was 20.5%, 18.2%, and 21.1 %, respectively. Normal ABRs were recorded in 27.3% of the ears despite marked thresholds elevation of the PTA at high frequencies. Other relationships between PTA results and ABR wave results were discussed. Conclusion: There were relationships between severity of noise-induced hearing loss indicated by PTA and the patterns of ABR wave abnormalities among workers with noise-induced permanent hearing loss.