[Standardized new method for measuring vibration perception]

The examination of the vibration perception is one of the basic measurements applied in the evaluation of the peripheral neuropathies in hand-arm vibration syndrome (HAVS) The detailed guidelines on how this kind of examinations should be performed, presented in the 1998 ISO standard, differ substantially from those currently binding in Poland. The aim of this study was to standardize the method of vibration perception measurements, taking account of the parameters consistent with the ISO recommendations, such as algorithm (stimulus presentation method), vibration frequency, the size and contact force of vibrating probe, as well as the comparison of the results obtained by means of both methods (ISO-recommended method and standard Polish method). It was found that the algorithm change (ascending method replaced by Bekesy's technique, recommended by ISO) did not affect the of the vibration perception thresholds values within the wide range of frequencies (32-500 Hz), whereas the decreased size of probe, pressed with smaller contact force, resulted in significantly higher values of perception thresholds within the frequency range of 125-400 Hz. The comparison of the outcomes of the ISO-recommended and Polish standard methods revealed that the perception thresholds did not differ at the frequency of 125 Hz, but at the frequencies of 250 and 400 Hz, the ISO-recommended method produced higher values. Moreover, at the frequencies ranging from 125 to 400 Hz, the results of the perception threshold measurements, taken several times in the same persons (intrasubject variability) by means of both methods, were more scattered. It was revealed that the measurements at the frequency range of 4-125 Hz should be included in the vibration perception examinations, and the certification of the ability to work in the conditions of exposure to hand-arm vibration should be based on their results. It is also essential that in the standard examination, a smaller vibratory probe (phi = 5 mm) and lighter contact force (0.1 N) than those currently used, should be applied.