Relation of digital arterial dysfunction to alternative frequency weightings of hand-transmitted vibration.

This study compared the relative performance of alternative frequency weightings of hand-transmitted vibration (HTV) to predict the extent of cold-induced vasoconstriction in the digital arteries of HTV workers. The cold response of digital arteries was related to measures of daily vibration exposure expressed in terms of r.m.s. acceleration magnitude normalised to an 8-h day, frequency weighted according to either the frequency weighting W_h defined in international standard ISO 5349-1:2001 (A_h(8) in ms^-2 r.m.s.) or the hand-arm vascular frequency weighting W_p proposed in the ISO Technical Report 18570:2007 (A_p(8) in ms^-2 r.m.s.). The measure of daily vibration exposure constructed with the frequency weighting W_p (A_p(8)) was a better predictor of the cold response of the digital arteries in the HTV workers than the metric derived from the conventional ISO frequency weighting W_h (A_h(8)). This finding suggests that a measure of daily vibration exposure constructed with the vascular weighting W_p, which gives more weight to intermediate- and high-frequency vibration (31.5-250 Hz), performed better for the prediction of cold induced digital arterial hyperresponsiveness than that obtained with the frequency weighting W_h recommended in ISO 5349-1 which gives more importance to lower frequency vibration (≤16 Hz).