BIOMECHANICAL AND EPIDEMIOLOGIC INVESTIGATION OF CARPAL-TUNNEL SYNDROME AT WORKPLACES WITH HIGH-RISK FACTORS

This paper deals with the problem of carpal tunnel syndrome (CTS) thro ugh investigations of both biomechanical and epidemiological data on s eventeen high risk jobs. Biomechanical data were collected from contin uous recording of prehension muscular efforts and wrist angular flexio n-extension positions for each hand. In order to characterize both sta tic and dynamic behaviours of signals, nine angle and four force indic es were built for each hand. The epidemiological data evaluated the pr obability to contract the CTS (prevalence) on the dominant hand, the n on-dominant hand, and both hands simultaneously. Biomechanical and epi demiological data were evaluated using multiple correspondence factor analysis which may consider heterogeneous variables to clarify non-lin ear relations in a very large data set. The CTS occurred twice more fr equently on the two hands together (average 20%) than on the dominant hand alone. Such a result confirmed the outcome of other studies that non-occupational factors could be more important than occupational fac tors. The prevalence for both hands was highly correlated with the fre quency of flexion and use of high forces. High or low flexions appeare d to be a greater risk factor than high or low extensions.