Factors influencing autonomic nervous function during cold-water immersion test in patients with hand-arm vibration syndrome.

OBJECTIVES: Factors influencing autonomic nervous function in patients with hand-arm vibration syndrome (HAVS) in response to cold-water immersion test with different water temperatures and immersion times were investigated in the summer and winter seasons. METHODS: Fourteen HAVS patients with vibration-induced white finger (VWF) and 14 healthy control subjects individually age-matched to the patients consented in writing and participated in this study. Patients and controls immersed their left hands in water at 10 degrees C for 10 min and at 15 degrees C for 3 min in summer and in winter in a room with temperature maintained at 21+/-1 degrees C. Electrocardiographic (ECG) data were recorded during the test period and the R-R intervals were analyzed with a fast Fourier transformation (FFT) program. Percentage of very low frequency (VLF%; indicator of both sympathetic and parasympathetic nervous function, and function of rennin-angiotensin system), low frequency (LF%; indicator of both sympathetic and parasympathetic nervous function), high frequency (HF%; indicator of parasympathetic nervous function), and LF/HF ratio (indicator of sympathetic nervous function) were calculated. The results by three-way analysis of variance (ANOVA) were reported elsewhere. In the present study, repeated measures ANOVA was used to re-analyze the factors of data measurement time (time factor) and group (group factor), and their interaction for each test method (water at 10 degrees C for 10-min immersion time; water at 15 degrees C for 3-min immersion time) in summer and winter. RESULTS: The HF% of HAVS patients tended to be lower than that of healthy controls throughout the cold-water immersion tests except for during tests involving water at 10 degrees C for 10-min immersion in summer. The group factor for HF% was statistically significant with an exception during the test involving water at 10 degrees C and 10-min immersion time in summer. The time factor for HF% was statistically significant with an exception during the test involving water at 15 degrees C and 3-min immersion time in winter. CONCLUSIONS: The findings of the present study indicated lower cardiac parasympathetic activity in HAVS patients than in healthy controls, especially in winter. The response of the autonomic nervous system to cold stimulation was to some extent more clearly observed during the immersion test with water at 10 degrees C and 10-min immersion time than during the immersion test with water at 15 degrees C and 3-min immersion time. The results revealed by three-way analysis in a previous study were similar to those in the present study with data analysis by repeated measures ANOVA.

Effects of room temperature, seasonal condition and food intake on finger skin temperature during cold exposure test for diagnosing hand-arm vibration syndrome.

For diagnosing the hand-arm vibration syndrome, peripheral circulation and sensory tests immersing one hand in cold water at 10 degrees C for 10 min have been performed widely in Japan. The authors investigated the effects of room temperature, seasonal condition and food intake on the test results, especially finger skin temperature. Six healthy males were examined repeatedly under six different room temperatures at 10 degrees C, 15 degrees C, 20 degrees C, 22.5 degrees C, 25 degrees C and 30 degrees C. Eight healthy males were examined under room temperatures at 10 degrees C, 20 degrees C and 30 degrees C, repeatedly in winter, spring, summer and autumn. Six healthy males were examined in summer under room temperature at 22.5 degrees C repeatedly 1 hr after, 3 hr after meal and after fasting for 13 hr. The finger skin temperature was strongly affected by room temperature. The finger skin temperature was also affected by seasonal condition. No remarkable effect of food intake was observed. For estimating circulatory function of the upper extremities using the finger skin temperature, the room temperature should be strictly controlled and the effect of seasonal condition must be taken into consideration.