Investigation of Hand Dexterity Changes in Response to Different Frequencies of Hand-transmitted Vibration

Aim: 
The use of hand-held vibrating tools exposes workers to hand–arm vibrations. In this study, the effect of hand-transmitted vibration (HTV) on hand dexterity in response to different vibration frequencies has been investigated.
Methods: 
Hand dexterity was examined in a controlled laboratory study involving 37 men exposed to 30 min of vibration with the same acceleration (5 m/s² rms) and different frequencies (31.5, 63, and 125 Hz). To assess hand dexterity, the Purdue Pegboard Test (PPT) was used, and the scores for both-hand activities and assembly tasks were recorded before and after each exposure scenario. The data were analyzed using SPSS22 software with descriptive statistics, paired comparisons, and repeated measures analysis of variance (ANOVA).
Results: 
The PPT scores significantly decreased after exposure to different HTV scenarios (P < 0.05). The results of the repeated measures ANOVA, conducted to compare the mean PPT scores across different sessions, indicated statistically significant differences in the effects of the various vibration scenarios (P < 0.05). Comparison of the scenarios revealed that as HTV increased, its impact on hand dexterity also increased. The greatest negative effect on hand dexterity was observed in the vibration scenario with an acceleration of 5 m/s² rms and a frequency of 125 Hz, with an effect size of 0.558, which indicates a moderate-to-large practical impact according to Cohen’s criteria.
Conclusion: 




The findings of this controlled laboratory study indicate that the frequency of HTV exposure, like the vibration acceleration, plays a significant role in affecting hand dexterity. The evidence suggests that as the frequency of HTV increases, hand dexterity decreases under constant vibration acceleration conditions.