Affective correlates of occupational exposure to whole-body vibration - A case-control study

Background: Exposure to whole-body vibrations (WBV) represents a highly diffuse occupational risk. Some studies report that chronic exposure to WBV induces a significant increment in the modifications of the cognitive and emotional area. The aim of this study was to investigate the long-term effects of WBV exposure on the neuropsychic and behavioural system. Methods: The study population consisted of 137 male subjects, mean age 45.7 years, working as drivers of mechanical trolleys and occupationally exposed to WBV of a frequency below 2 m/s(2). The Profile of Mood States was administered to all subjects in a maximum time of 10 min and in the same operative conditions. The results were compared with those of a homogeneous control group by means of an innovative statistical technique. Results: The results show a significant difference in the response to the neurobehavioural test. The exposed group showed, in fact, a higher score compared with the controls for all 6 factors. In particular, the scores for factors F (fatigue-inertia), D (depression-dejection) and T (tension-anxiety) were more elevated, expressing a significant alteration of the psycho-affective status. Moreover, statistical analysis showed a correlation between exposure time and the score obtained for all factors in the exposed group. Conclusion: This study indicates that occupational exposure to WBV is associated with alterations of mood status and that these modifications are directly proportional to exposure time. Furthermore, our results show that psychological tests commonly used in psychopathologic diagnostics can be useful in monitoring alterations of psycho-emotional status determined by physical stressors.