ABSTRACT
To clarify the effects of Silver Spike Point (SSP) therapy on the autonomic nervous function, we evaluated changes in the peripheral circulatory function by second derivative photoplethysmogram (SDPTG) on 22 workers exposed to hand-arm vibration. We also examined the responses of the autonomic nervous function using the coefficient of variation of R-R interval (CV<sub>R-R</sub>), total number of white blood cells (WBC), and the ratio of granulocyte (GC) and lymphocyte (LC) as indexes.<br>As a result, we observed improved peripheral circulation due to the SSP therapy, in which the average pulse rare (PR) tended to decrease, CV<sub>R-R</sub> was not significantly changed by the therapy, and WBC and LC were significantly decreased by the therapy.<br>The 22 subjects were divided into two groups (low-value group, 8 subjects; high-value group, 14 subjects) according to the data of CV<sub>R-R</sub> revised using Fujimoto's method. In the low-value group, PR tended to decrease, and SDPTG-index and c/a tended to increase. In the high-value group, on the other hand, CVR-R and LC tended to decrease and WBC significantly increased.<br>In conclusion, SSP therapy enhanced the parasympathetic nervous function and improved the peripheral circulatory function in the parasympathetic-nervous-function-impaired the group (low-value group). Furthermore, it suppressed the parasympathetic nervous function without affecting the peripheral circulatory function in the parasympathetic-nervous-function-enhanced group (high-value group).