| A system facilitating real-time monitoring and evaluation of relative finger blood flow was developed. System components were: a vibration source, LEDs (light emitting diodes), photosensitive diodes, differential amplifiers, A/D boards, a computer and signal acquisition and processing software. The system was validated by demonstrating its signal reproducibility. This system was able to monitor and analyze relative finger blood flow not only before or after vibration, but also during vibration. The following results were obtained from experiments with human subjects. (1) The physiological meaning of relative finger blood flow signals was explained. (2) The correlation coefficient between vibrated and non-vibrated hand relative finger blood flow in the student group, which had experienced no occupational hand-arm vibration previously, was significantly higher than that of the worker group, which had substantial occupational hand-arm vibration exposure. However, during vibration, the correlation of vibrated and non-vibrated hand relative finger blood flow in both groups decreased significantly. (3) For the pre-vibration phase, the net amount of relative blood entering the finger was equal to the net amount of relative blood leaving the finger. (4) During vibration, relative finger blood flow in the student group increased, while that of the worker group decreased or remained unchanged when compared with the pre-vibration phase. (5) After vibration and during the recovery period, relative finger blood volume in both groups decreased when compared with the pre-vibration phase. |
