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- Burström, Lage, 1954-, et al.
(författare)
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Acute effects of vibration on thermal perception thresholds
- 2006
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Ingår i: Diagnosis of injuries caused by hand-transmitted vibration - 2nd International workshop, Göteborg, 2006. - : Springer Science and Business Media LLC.
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Konferensbidrag (refereegranskat)abstract
- Objective This study focuses on the acute effects of vibration and how vibrations influence the measures of the thermal perception thresholds during different vibration magnitudes, frequencies, and durations.Methods The fingers of ten healthy subjects, five males and five females, were exposed to vibration under 16 conditions with a combination of different frequency, intensity and exposure time. The vibration frequency was 31.5 and 125 Hz and exposure lasted between 2 and 16 min. The energy-equivalent frequency weighted acceleration, according to ISO 5349-1, for the experimental time of 16 min was 2.5 or 5.0 m/s(2) (r.m.s.), corresponding to a 8-h equivalent acceleration, A(8) of 0.46 and 0.92 m/s(2), respectively. A measure of the thermal perception of cold and warmth was conducted before the different exposures to vibration. Immediately after the vibration exposure the acute effect was measured continuously on the exposed index finger for the first 75 s, followed by 30 s of measures at every minute for a maximum of 10 min. If the subject's thermal thresholds had not recovered, the measures continued for a maximum of 30 min with measurements taken every 5 min.Results For all experimental conditions and 30 s after exposure, the mean changes of the thresholds compared with the pre-test were found to be 0.05 and -0.67C for the warmth and cold thresholds, respectively. The effect of the vibration exposure was only significant on the cold threshold and only for the first minute after exposure when the threshold was decreased. The warmth threshold was not significantly affected at all. The frequency and the exposure time of the vibration stimuli had no significant influence on the perception thresholds for the sensation of cold or warmth. Increased equivalent frequency weighted acceleration resulted in a significant decrease of the subjects' cold threshold, not the warmth. The thresholds were unaffected when changes in the vibration magnitude were expressed as the frequency weighted acceleration or the unweighted acceleration.Conclusion When testing for the thermotactile thresholds, exposure to vibration on the day of a test might influence the results. Until further knowledge is obtained the previous praxis of 2 h avoidance of vibration exposure before assessment is recommended.
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| 2. |
- Toomingas, Allan, et al.
(författare)
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Incidence and risk factors for symptoms from the eyes among professional computer users
- 2012
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Ingår i: Work-a Journal of Prevention Assessment & Rehabilitation. - : IOS Press. - 1051-9815 .- 1875-9270. ; 41:Supplement 1, s. 3560-3562
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Tidskriftsartikel (refereegranskat)abstract
- Personal computers are used by a majority of the working population in their professions. Little is known about risk-factors for incident symptoms from the eyes among professional computer users. The aim was to study the incidence and risk-factors for symptoms from the eyes among professional computer users. This study is a part of a comprehensive prospective follow-up study of factors associated with the incidence of symptoms among professional computer users. 1531 computer users of different professions at 46 companies were invited, whereof 1283 answered a baseline questionnaire (498 men; 785 women) and 1246 at least one of 10 monthly follow-up questionnaires. The computer work-station and equipment were generally of a good standard. The majority used CRT displays. During the follow-up period 329 subjects reported eye symptoms. The overall incidence rate in the whole study group was 0.38 per person-year, 0.23 in the subgroup of subjects who were symptom free at baseline and 1.06 among subjects who reported eye symptoms at baseline. In the bivariate analyses significant associations were found with all explanatory variables, except BMI. The reduced multivariate model showed significant associations with extended computer work, visual discomfort (dose-response), eye symptoms at baseline (higher risk), sex (women=higher risk) and nicotine use. The incidence of eye problems among professional computer users is high and related to both individual and work-related factors.
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