Response to Psychological Test in Elderly Patients with Hand-Arm Vibration Syndrome and Healthy Controls.

Abstract

We investigated the parasympathetic nervous response to psychological test using heart rate variation (HRV) during deep breathing in elderly patients with hand-arm vibration syndrome and healthy controls. Average age (SD) of 16 patients with vibration-induced white finger (VWF), 13 patients without VWF and 12 healthy controls was 60.1 (2.8), 60.6 (4.2) and 58.8 (3.8), respectively. After an initial supine rest for 40 min, psychological test (Stroop color word test and mirror drawing test) was performed for 20 min. The indexes of HRV (Mean R-R, SD, RMSSD and CV) were calculated. Blood pressure and heart rate were also measured. The indexes of HRV did not differ between the groups before exposure. The SD, RMSSD and CV of the patients without VWF during supine deep breathing after 3 min post-exposure supine rest were significantly lower than those of the control group (p<0.05). The Mean R-R of the patients without VWF significantly increased (p<0.05). Blood pressure did not differ in either before or after exposure measurements. The results suggest that the post-exposure response of the parasympathetic nervous system to psychological test reduced in the patients without VWF. Key words:Hand-arm vibration syndrome, Psychological test, Parasympathetic responseVibration-induced white finger, Heart rate variation, It has been suggested that exposure to hand-arm vibration might affect autonomic nervous functions and has been demonstrated on the basis of subjective symptoms complained with higher prevalence rates by patients with hand-arm vibration syndrome than healthy controls" 2).In clinical neurology the responses of cardiovascular reflexes have been used to examine the function of the autonomic nervous system3° 4). It has been accepted that respiratory sinus arrhythmia in supine deep breathing is vagally mediated, and variation of heart rate parameters due to respiratory arrhythmia is considered as an indicator of the parasympathetic nervous functions' 6)In this study, we examined a group of elderly patients with hand-arm vibration syndrome and healthy controls to *To whom correspondence should be addressed .evaluate the parasympathetic nervous activity using heart rate variation. Because the heart rate variation decreases with increasing age's, we manipulated levels of cardiac sympathetic and parasympathetic activity of the subjects exposing them to psychological test and measured R-R intervals in supine deep breathing before exposure and after 3 min post-exposure supine rest. Blood pressure and heart rate were also measured. We studied 41 male subjects. Sixteen of them with agerange 55 to 66 (60.1 ± 2.8) years, were workers exposed to vibration and experienced attacks of vibration-induced white finger during the past year (VWF(+) group), 13 with agerange 54 to 65 (60.6 ± 4.2) years, were workers exposed to vibration but did not experience attacks of vibration-induced white finger (VWF(-) group) and 12 healthy workers with age-range 51 to 61(58.8 ± 4.0) years, were examined as a

Heart Rate Variability in Occupational Health ―A Systematic Review

“…Workers with hand-arm vibration syndrome showed decreased HF and LF components during rest when compared with healthy workers 31) . In addition, SDNN and RMSSD decreased in workers with hand-arm vibration syndrome without vibration-induced white finger 32) . Hand-transmitted vibration may also cause persistent damage to nerves and blood vessels in the upper limbs or the higher centers of the autonomic nervous system.…”

“…Laskar et al reported that workers with hand-arm vibration syndrome showed significantly decreased HF and LF components during rest 31) and significantly decreased SDNN and RMSSD during rest after a psychological test when compared with the healthy controls 32) . Among operators with vibration-induced white finger, the LF/HF ratio increased significantly during immersion of the hand in cold water at 10˚C, but did not increase in healthy controls 33) .…”

Assessment of autonomic nervous activity in hand-arm vibration syndrome patients using time- and frequency-domain analyses of heart rate variation

“…The frequency-domain analysis of HRV has been used recently [1,34]. There are several reports on HRV in HAVS patients using time-domain analysis [2,12,13,14,15,19,22,36], whereas only two reports of frequency-domain analysis are available [17,27].…”