Two methods of vibration perception assessing in workers exposed to hand-arm vibration

It is known that vibration perception could be influenced
by the device parameters and technique of measurement. The influence of
confounding factors like age, weight and height on VPTs values was assessed in
previous analyses in non-exposed subjects. The aim of present study was to
compare the results of two techniques of vibrotactile thresholds measurement in
workers exposed to hand-arm vibration. Two methods of vibration perception
assessment were compared in 124 workers (21-62 years old, 1-40 years of
employment) exposed mainly to hand-arm vibration during the work as: chain saw
operator, pneumatic hammers operators, metal grinders, fitters, dentist
technician. One method (named "standard method") has been used in Poland so far;
the second one (named "according to ISO method") was established on the base of
ISO Standard 13091-1-2001. The methods differed not only in technical parameters
of stimuli but also in the way of normative values evaluation. In standard
method there were no individual features or habits included. The results of
investigation revealed that age and weight play the important role in
interpretation of tests results, both in standard and according to ISO method.
Moreover, standard method measurements seem to overestimate the number of
subjects with recognized vibration sense abnormalities. In both methods exposure
to vibration mostly could be revealed by stimuli at frequencies of 125 and 250
Hz.