A field-implementable measure is needed to estimate the attenuation workers are achieving with their hearing protectors in the field. Alternative measures for assessing a hearing protector's effectiveness were evaluated through comparison to the standardized real-ear attenuation at threshold (REAT) method, termed 1I3-REAT, a psychophysical procedure (ANSI S3.19-1984). One alternative deviated from the standardized procedure primarily through utilizing a pure-tone audiometer coupled to an amplifier and loudspeaker for the sound field presentation of pure tones (Pr -REAT). The other alternative. tenned microphone in real-ear (MIRE), used miniature microphones in each concha and just outside of each of the subject's two ears to physically measure the attenuation of the protector using both insertion loss (lL-MIRE) and noise reduction (NR-MIRE) procedures. Comparisons between the alternative measures were made across nine 113 octave bands centered at 125, 250, 500, 1000, 2000, 3150,4000, 6300, and 8000 Hz. The experiment also explored a means for predicting broadband attenuation from data of a single 113 octave band through a regression analysis for both PT -REAT tests and NR-MIRE tests. Results showed that when comparing the PT -REAT test and the standardized 1/3-REA T method, the standardized method exhibited significantly greater attenuation at most of the 1/3 octave bands tested. The difference, however, may be due to the higher ambient noise levels present in the pure tone condition. The MIRE measures also showed some significant differences with the standardized 1/3-REAT method for the values collapsed across protectors, with the direction of the difference changing with test band. At 125 Hz, the MIRE metrics yielded significantly lower attenuation, while from 500 to 6300 Hz, the 1/3-REAT method generally yielded significantly lower attenuation. These differences may be due in part to the occlusion effect and the bone conduction of sound. In general, however, the size and consistency of the differences across hearing protection devices (HPDs) suggest that PT-REAT and MIRE measures hold promise for providing quick and relatively accurate estimations of an HPD's attenuation in the field. Results of the regression analyses indicated that single test band data obtained at 250 and 500 Hz, from both PT-REAT and NR-MIRE metrics, provided the best predictions for the hearing protectors tested in this study, based on their Pearson product-moment correlation coefficients. / Ph. D.

The need for hearing protection in industry has evolved from the growing awareness of the detrimental effects of noise on hearing and recent legislation enacted to protect the hearing of noise-exposed employees through the use of hearing conservation programs. In lieu of expensive or impractical engineering and administrative controls, personal hearing protection devices (HPDs) are considered to be the most practical and effective means of protecting employees from the damaging effects of noise in industry today.

Syftet med denna studie är att undersöka hur musiker ser på begrepp som ljudnivå, musikupplevelse och relationen mellan dessa. Underlaget för studien är sex intervjuer med musiker och ljudtekniker, med och utan hörselskador. Studien byggs på sex kvalitativa intervjuer och är avgränsad till att i första hand behandla detta inom musikstilar vilka är baserade på trummor och bas – pop/rock, jazz/blues. Studiens resultat visar att parametrar som t.ex. genre, lokal, ljudteknik, ljudtekniker och arrangör har inverkan på det ljud och den ljudnivå som uppnås vid en konsert. Vidare redovisas respondenternas syn på relationen mellan ljudnivåer och musikupplevelse. Samtliga respondenter menar att ljudvolymen har en stor betydelse för den musikaliska upplevelsen och att faktorer som lokalens utformning och musikens genre har stor betydelse för upplevelsen av lämplig ”ljudbild”. / The purpose of this study is to investigate musicians’ opinions about terms such as sound level, musical experience, and the relation between them. The basis for the study is six interviews with musicians and sound engineers, some with and some without hearing disorders. The study is limited to primarily focus on musical styles that are based on drums and bass – jazz/blues, pop/rock. The result demonstrates that parameters like genre, room, technical equipment, sound engineers and arrangers all have influence on the sound and the sound level at a concert. Also – the respondents’ different views on the relationship between sound level and musical experience are presented. All the respondents think that volume is of great significance for the total experience of the music and the feelings it brings. They also believe that factors like the interior and form of the room/venue and the musical genre are of great importance for the experience of proper sound and sound environment.

The main purpose of this study was to investigate whether a difference existed between attitudes, subjective norms, and behavioral intentions of employees regarding self reported use or nonuse of PHPD. The study also investigated if there was a difference between selected demographic variables and the attitudes, subjective norms, and behavioral intentions of employees regarding use or nonuse of PHPD. Fishbein and Ajzen's (1975) Theory of Reasoned Action was the theoretical framework for this study. A convenience sample of 250 employees at two automotive component manufacturing plants located in the Midwest completed the demographic sheet and Employee Use of PHPD questionnaire.Cronbach's alpha coefficient was used to determine the internal consistency of the questionnaire subscales, and the alpha scores ranged from 0.66 to 0.81. Findings revealed a significant difference in attitudes between the self reported use and nonuse groups (F=93.34, df, 1, p<.0001). A significant difference in subjective norms between the use and nonuse groups (F=52.14, df, 1, p<.0001). Findings also revealed a significant difference in behavioral intentions between the self reported use and nonuse groups (F=128.54, df, 1, p<.001). A significant difference was found between age, gender, and self reported use or nonuse ofPHPD. Younger female respondents used PHPD more frequently than male middle aged respondents.Despite the fact that this study found evidence of positive attitudes and subjective norms, the findings did not support behavioral intentions. Most of the respondents (86.4%) supported the use of PHPD as an important part of responsible work safety, but their self reported use of PHPD was only 33.4%. More than half (65.6%) of the respondents reported never or almost never using PHPD. The findings were not consistent with the constructs of TRA, that attitudes and subjective norms are predictive of behavioral intention and thus behavior. / School of Nursing

Submitted in fulfillment of the requirements for the degree of Doctor of Technology: Quality Management, Durban University of Technology, 2014. / Hearing conservation in the industrial setting has mainly focussed on the harmful effects of noise exposure on the auditory system. This study investigated the co-exposure to noise and ototoxic chemicals on the auditory system of workers engaged by labour brokers. It examined the adequacy of current occupational health and safety legislation to address chemically induced hearing loss and makes recommendations at a policy level to protect workers’ hearing at the workplace. This study is an exploratory cross-sectional field case study in an industrial setting. A sample of 300 workers was drawn from a rubber factory involved in the manufacture of components for the motor, shoe and plumbing industries in the metropolitan area of Durban. Purposive sampling was undertaken amongst a cohort of day shift workers which constituted the research subjects. The research tools used in the study included the completion of the NoiseChem questionnaire, conducting pure tone audiometric testing on research subjects, monitoring noise exposure levels and performing chemical air monitoring of the ambient environment. This study confirms that a segment of the research subjects were exposed to both ototoxic chemicals and noise. Chemical exposure of research subjects was within legal permissible limits in most instances. Noise exposure exceeded the noise rating limit of 85 dBA in certain work areas. Multiple regression analysis revealed that there was a slight trend towards co-exposure to chemicals and noise being risk factors for hearing loss with an odds ratio of 1.7 (95% CI = 0.34 – 8.57) but the p value was not significant. No significant association with hearing loss was evident for workers exposed to chemical only with odds ratio of 0.41 (95% CI = 0.11 – 1.53, p = 0.19) and noise only with odds ratio of 0.87 (95% CI = 0.32 – 2.31, p = 0.78). The study indicated that workers exposed to both ototoxic chemicals and noise may be more susceptible to hearing loss in their current jobs. The study draws attention to policy gaps in the Occupational Health and Safety Act and proposes changes to address the shortcomings. / D