2011-12-01 12:00 - Messages

High-frequency audiometry is more sensitive to detect noise-induced hearing loss than conventional audiometry

Early diagnosis of NIHL can help prevent the progression of hearing loss, especially in speech frequencies. This study compared hearing threshold and prevalence of hearing loss in conventional and high frequencies of audiometry among textile workers. Hearing loss was more common in HFA than conventional audiometry. HFA is more sensitive to detect NIHL than conventional audiometry. It can be useful for early diagnosis of hearing sensitivity to noise, and thus preventing hearing loss in lower frequencies especially speech frequencies.

Source : High-frequency audiometry: A means for early diagnosis of noise-induced hearing loss. Mehrparvar, A.H. et al. Noise and Health, 2011, 13, 55, pp. 402-106. DOI: 10.4103/1463-1741.90295



Stress and difficulty communicating in the chemotherapy clinic

This study measured the noise levels in the Portland Veteran's Affairs Medical Center's outpatient chemotherapy clinic. Patients, visitors, and staff members filled out anonymous surveys regarding their reactions to noise levels. Noise measurement analysis indicated that levels were at or above 70 dB SPL for less than ten minutes during the 11-hour recording window. The patient and visitor surveys indicated that both groups were unbothered by noise in the clinic. However, most staff members were bothered by or concerned about noise levels, and many felt that it caused stress and difficulty communicating on the phone.

Source : Ambient noise levels in the chemotherapy clinic. Gladd, D.K., Saunders, G.H. Noise and Health, 2011, 13, 55, pp. 444-451. DOI: 10.4103/1463-1741.90322


L’exposition cumulée élevée à des forces ou vibrations transmises au membre supérieur est associée à la survenue de la maladie de Dupuytren.

La maladie de Dupuytren est une affection courante dont la prévalence varie de 4 à 10 % dans la population adulte, selon les études. Elle a pour conséquence une flexion irréductible d'un ou plusieurs doigts. Bien que généralement indolore, celle-ci peut générer un handicap majeur. 14 articles répondant aux critères de qualité prédéfinis ont été inclus dans une méta-analyse. Celle-ci retrouve une association significative entre le travail manuel et la maladie de Dupuytren ainsi que l'exposition aux vibrations. L'existence d'autres facteurs de risque, notamment une prédisposition génétique, n'est pas suffisante pour remettre en cause cette relation potentiellement causale avec les conditions de travail. En conclusion, une association entre  l'exposition cumulée  élevée aux contraintes physiques (force ou vibrations transmises au membre supérieur) est associée à la survenue de la maladie de Dupuytren.

 Source : La maladie de Dupuytren peut-elle être d'origine professionnelle ? Revue et méta-analyse d'un vieux débat.  Descatha A, Jauffret P, Chastang J-F, Roquelaure Y, Leclerc A. Should we consider Dupuytren's contracture as work-related ? A review and meta-analysis of an old debate. BMC Musculoskelet Disord. 2011 ; 12 : 96. Période : mars 2011 à août 2011

Tiré de Anses, Bulletin de veille scientifique no 16, Santé / Environnement / Travail, Décembre 2011, p.36.


Noise induced hearing loss – Audio demonstration by the Health and Safety Executive, UK

Noise induced hearing loss is irreversible damage to the ears caused by exposure to high levels of noise. A recording on HSE site demonstrates how hearing is gradually lost over a working life: «Noise induced hearing loss – Audio demonstration reveals potential effects». You can also 'see' the sort of damage that excessive noise can cause inside your ears; the clip has been reproduced from "The Hearing Video" by the kind permission of WorksafeBC.


Source: Latest automated update(s) to Noise on HSE's Website: 17-11-2011 http://www.hse.gov.uk/noise/demonstration.htm#?eban=govdel-noise&cr=17-Nov-2011

The original film on damage to the ears can be seen at WorkSafeBC Videos - The Hearing Video http://www2.worksafebc.com/Publications/Multimedia/Videos.asp?reportid=34284

Study recommandations to greatly reduce the transmission of vertical vibration to the operator.

Vibratory soil compactors are articulated vehicles designed to achieve efficient compaction of the soil and road base-layers through a vibratory drum/roller integrating an unbalanced rotating mass. The low frequency whole-body vibration are directly transmitted to the operator through the driver seat, which in the vast majority of the vehicles employed in Québec is limited to a polyurethane foam cushion. The results of this study suggest that the seat and the cabin mounts amplify the low frequency vibration for all the vehicles considered but this amplification is limited for the 13-ton compactor equipped with more sophisticated cab mounts. Furthermore, the dominant vibration in both compaction and travel modes occurred along the vertical axis, particularly for the 10-ton compactors that represent the largest proportion of such vehicles used in Québec. The transmission of vertical vibration to the operator could be greatly reduced through design and implementation of an adequately tuned suspension seat. The authors recommend actions to limit the vibration amplification. Analytical and simulation methods need to be developed to explore alternate designs of cabin and drum mounts for limiting the vibration exposure while preserving the compaction efficiency of the vehicle.

Evaluation of whole-body vibration exposure of operators of soil compactors(Évaluation de l'exposition aux vibrations globales du corps des opérateurs de compacteurs de sol). Rakheja, Subhash; Kordestani, Ario; Marcotte, Pierre
Studies and Research Projects / Report R-709, Montréal, IRSST, 2011, 72 pages.

Models of the substructures of the hand-arm system can be used to help design and analyze palm and orbital sanders

Prolonged, intensive exposure to vibrations from palm and orbital sanders could cause finger disorders. They are associated with the biodynamic responses of the fingers. This study confirmed that the distributed hand responses generally varied with locations on each finger, vibration frequencies, and applied hand force. This study enhanced the understanding of the biodynamic responses of the fingers and hand exposed to vibrations on a contact surface with a large effective radius such as that found on palm and orbital sanders. These results are useful for developing hand and finger models required for the designs and analyses of tools and anti-vibration devices. Models are also required for quantifying vibration exposure and frequency weighting.

Source: The vibration transmissibility and driving-point biodynamic response of the hand exposed to vibration normal to the palm. Xueyan S. Xu, Daniel E. Welcome, Thomas W. McDowell, John Z. Wu, Bryan Wimer, Christopher Warren, Ren G. Dong. International Journal of Industrial Ergonomics Volume 41, Issue 5, September 2011, Pages 418-427.


Mid-level transient sound occurrence rates significantly correlated to perceived annoyance and loudness levels

Intensive care units (ICUs) have important but challenging sound environments. Alarms and equipment generate high levels of noise and ICUs are typically designed with hard surfaces. A poor sound environment can add to stress and make auditory tasks more difficult for clinicians. Two units with similar patient acuity and treatment models showed little differences based on traditional overall noise measures. The objective differences between the two occupied sound environments emerged only through a more comprehensive analysis of the “occurrence rate” of peak and maximum levels, frequency content, and the speech interference level. Furthermore, mid-level transient sound occurrence rates were significantly and positively correlated to perceived annoyance and loudness levels.

Source: Soundscape evaluations in two critical healthcare settings with different designs. Selen Okcu, Erica E. Ryherd, Craig Zimring, and Owen Samuels.  J. Acoust. Soc. Am. Volume 130, Issue 3, pp. 1348-1358 (2011).



Firefighters may be at an increased risk of exposure to high noise levels

45 male firefighters, aged 41.0 years with around 14 years of experience were followed up to characterize their exposures to noise and carbon monoxide. Noise levels were significantly greater on day shifts, among firefighters in non-supervisory jobs, for those working on engine and rescue trucks, by number of emergency calls they attended and in particular for motor vehicle accident (MVA) and building alarms calls, if subjects worked near or used fire equipment, or if they participated in active firefighting training activities. 1% of CO samples exceeded occupational limits, both full-shift and peak CO levels were significantly correlated by number of MVAs and building alarms calls. The authors concluded that firefighters may be at an increased risk of exposure to high noise levels, but CO exposures were lower than anticipated.

Source: Characterization of Noise and Carbon Monoxide Exposures among Professional Firefighters in British Columbia. Tracy L. Kirkham, Mieke W. Koehoorn, Hugh Davies and Paul A. Demers. Oxford Journals Medicine &  The Annals of Occupational Hygiene Volume55, Issue7 Pp. 764-774.


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