Biomedical subjects

H Virokannas

Publications and source records attributed to H Virokannas.

5 recordsLinked to original sources

PubMed1992

Vibration perception thresholds in workers exposed to vibration.

The vibration perception thresholds (VPT) at six frequencies from 16 to 500 Hz were examined in 77 workers exposed to hand-arm vibration and in 77 controls using a limits procedure. A dose-response relationship between VPTs and exposure to vibration was found, and the age-adjusted VPTs at each frequency were higher in workers exposed to vibration than in controls. Carpal tunnel syndrome (at 250 Hz) and consumption of alcohol (at 125 Hz) significantly increased the VPT, but vibration-induced white finger was not correlated with VPT. Indices for low (16 and 32 Hz) and high (63-500 Hz) VPT frequencies were calculated to evaluate the entire vibrogram, which consisted of several frequencies with two numbers. The results showed that hand-arm vibration disturbs first the high frequencies, and that the disturbance spreads thereafter to the low frequencies. The characteristics of the VPT test regarding vibration exposure and the association between VPT and nerve symptoms in the hand support the view that VPT is a useful measure for vibration-induced sensory nerve damage.

Arm↗

PubMed1991

Finger blood pressure and rewarming rate for screening and diagnosis of Raynaud's phenomenon in workers exposed to vibration.

Both the finger systolic blood pressure (FSP) and the rewarming test of finger skin are measures of circulation in the finger; the first reflects the vasoconstriction phase and the second the vasodilatation phase. The combinations of the specificity and the sensitivity of these methods were evaluated by a receiver operating characteristic curve (ROC). The material included 37 vibration-induced white finger (VWF) cases, five primary Raynaud's cases, and 37 controls. The specificity of the FSP test was high with regard to the anamnesis of white finger and the test was useful for the diagnosis of Raynaud's phenomenon, but the sensitivity was too low for screening. The rewarming test was useful for screening primary Raynaud's case and possibly for screening disorders in peripheral vasodilative function. The connections between the rewarming test and VWF are not clear and according to the present study the rewarming test was not suitable for screening VWF.

Adult↗

PubMed1991

Frostbite in reindeer herders.

The aim of this study was to determine the prevalence of frostbite among reindeer herders and to clarify the co-factors that may relate to these injuries. 2081 (60%) male reindeer herders in Finland were asked information on frostbite. Logistic regression analysis was used for studying the effect of potential co-factors. 453 men (22% of the respondents) reported frostbites during the last twelve months, the areas most affected being the face, fingers and toes. The amount of time spent in snowmobile driving, white finger symptom and the area of reindeer herding proved to be significant explanatory factors. Since the majority of frostbites were associated with snowmobile driving in spite of protection and adaptation to cold, it seems that new technology has not solved all the problems of the working conditions in a cold environment.

Adult↗

PubMed1990

Cardiovascular reflexes in workers exposed to hand-arm vibration.

In the present study autonomic function was observed by measuring cardiovascular reflexes. The quiet breathing test, the deep breathing test and the Valsalva manoeuvre were used. The aim was to study the effects of long-term exposure to hand-arm vibration on the cardiovascular reflexes. The study group included 47 workers (lumberjacks and railroad workers) who were exposed to hand-arm vibration. 36% of the subjects had vibration induced white finger (VWF). Comparisons were also made with 5 primary Raynaud's cases. The changes of the R-R interval in the quiet and deep breathing tests had a significant negative correlation with the ages of the subjects. In all the results there was no evidence that hand-arm vibration could cause autonomic dysfunction in general, but there were signs that it could reduce the autonomic function among workers who are susceptibility to developing white finger reactions. Also, it is possible that the primary Raynaud's cases had reduced cardiovascular reflex responses.

Adult↗

PubMed1989

[Cold weather work].

Explore the source record for details and available documents.

Body Temperature Regulation↗