A corollary to industrialization and urbanization is a significant increase in noise levels. In many industrial settings, the noise levels are such that they are potential health hazards. There are many studies which suggest that prolonged exposures to high noise levels have a negative impact on various aspects of human physiology. However, not much work has been conducted in studying the effects of various noise frequencies in the industrial environment. This paper has made an attempt to identify various noise frequency components to which the workers of six major industries in Mysore (Karnataka State, India) are being exposed, and their effects on the physical, physiological, and psychological systems of the working community with respect to their noisy industrial environment. The study results showed that the sampled industrial workers were repeatedly being exposed to noise of dominant low- and mid-octave band center frequencies. It is found that symptoms such as 'eye ball pressure,' 'awakening from sleep,' 'pains in neck,' 'frequent ear vibration,' 'chronic fatigue,' 'repeated headache,' 'backache,' and 'repeated ear pulsation' are observed to be highly associated with low- and mid-octave band center frequency noise exposure among the sampled workers. Furthermore, among the major psychological symptoms identified to be associated with octave band center frequencies, it is evident that 'irritability' is highly associated with low- and mid-octave band noise frequency characteristics.

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The purpose of the present article is to review comfort studies on hearing protector devices. Comfort is probably the most important dimension for long-term worker acceptance and effective wear of hearing protectors in noise. A short digression has been made to introduce comfort work from the textile and clothing industries where models of comfort have been attempted and comfort research is much more sophisticated. Finally, presented are some recent efforts by NIOSH to examine issues of hearing protector comfort in greater detail. These efforts include a field study of a semi-custom earplug hearing protector.

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Millions of people around the world are exposed to industrial organic solvents such as toluene and xylene in the manufacturing sectors. Solvents are neurotoxic substances that are detrimental to the functioning of the nervous system, including the central auditory nervous system (CANS). This study investigated hearing and auditory processing in seven individuals with a history of exposure to industrial solvents. A battery of audiological tests was administered to all subjects: pure tone, speech, and impedance audiometry, otoacoustic emissions tests, auditory brainstem responses, middle latency responses, as well as the SCAN-A and R-SPIN tests with low predictability sentence lists. All individuals in this study exhibited findings consistent with retrocochlear and/or central abnormality. Two of the seven subjects in this study had normal pure tone thresholds at all frequencies bilaterally, yet showed abnormal retrocochlear/central results on one or more tests. The auditory test battery approach used in this study appears to be valuable in evaluating the pathological conditions of the CANS in solvent-exposed individuals.

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Background: Noise is the most common agent of occupational exposure. It may induce both auditory and extraauditory dysfunction and increase the risk of work accidents. The purpose of this study was to estimate the fraction of accidents attributable to noise occupational exposure in a mid-size city located in southeastern Brazil. Materials and Methods: In this population case-control study, which included 108 cases and 324 controls, the incidence rate ratio of work accidents controlled for several covariables was obtained by classifying occupational noise exposure into three levels, as well as determining the prevalence in each level. Results: Based on these data, the attributable fraction was estimated as 0.6391 (95% CI = 0.2341-0.3676), i.e., 63% of the work accidents that took place in the study site were statistically associated with occupational noise exposure. Discussion: The causes of this association as well as its implications in the prevention of work accidents are discussed.

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