بررسی تجربی سطح ناتوانی عملکرد دستی ناشی از مواجهه با ارتعاش دست بازو در کارگران شاغل در یک صنعت ریخته گری

Background: Exposure to hand-arm vibration is one of the most common physical harmful factors. The purpose of this study was Experimental study of  the level of manual performance disability caused by exposure to hand-arm vibration among automobile casting workers.  Methods: This study was performed on 53 casting workers as case group and 28 controls as control group. The measurement of the vibration of the worker's arms and hands was carried out in accordance with the ISO 5349 standard. The level of manual performance disability was evaluated using skeletal-muscular, sensory-neural and vascular tests. Also, a questionnaire was used for the level of disability of the arm, shoulder and hand DASH. Data were analyzed using SPSS16 software.  Results: The 8-hour vibration exposure was 8.33 m / s2 (4.49), which is exceeded the permissible level. Skill and dexterity, fingers and grip strength of the dominant hand in the case group were decreased by 4%, 13.3% and 11%, respectively (p <0.05). The regeneration time of the dominant hand in the case group was 41.2% higher than the control group (p <0.05). Sensory-neurological complications increased in the case group compared to the control group, however, it was not statistically significant. The DASH score in the case group was 10.7 (13.4) and the control group was 4.1 (5.1).  Conclusion: Hand-arm manual performance disability in workers exposed to vibration decreased from 4% to 14%, which confirmed the DASH score. In addition, workers showed a higher level of vascular complications compared with sensory-neurological complications.