Assessment Methods for Restrictions in Manual Dexterity: Suitability for Exposure to the Cold
CENTRAL INST OF THE FEDERAL ARMED FORCES MEDICAL SERVICES KOBLENZ (GERMANY)
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Manual work e.g. operating machinery or installation and assembly tasks are of great importance in civilian everyday life and military standard duties. However, numerous circumstances carrying loads, exposure to cold etc. may lead to restrictions in manual dexterity or coordination and reduction in hand grip strength. Thus, suitable assessment methods are needed to quantify such effects. A steadiness test to quantify hand-steadiness and a method to measure hand-grip strength have been successfully deployed to assess changes in hand tremor as well as in force-time courses of hand-grip strength before and after stretcher carriage. In this study, both methods were tested for their suitability to detect changes in hand tremor and manual work performance while the hands were exposed to cold. Additionally, a screwbolt skill test was modified to represent common construction and assembly tasks. 16 male subjects were exposed to cold 1 h in a climate chamber -5 deg C, vair 1 ms. Subjects were moderately physically active and adequate thermal insulation of the body approx. 2 clo was provided. Before and during cold exposure, the screwbolt skill test and the hand-steadiness test were administered and measurements of hand-grip strength were taken. The study included two different conditions bare hands all the time vs. gloves, removed after the screwbolt skill test. Due to mechanical and haptical encumbrance, time to completion Mean or - SD was significantly longer with gloved hands compared to bare, cold hands in the screwbolt skill test 220 or - 52 s vs. 134 or -5 s p0.001. This test appears suitable to determine the extent of encumbrance caused by gloves. The hand-steadiness test showed an increased number of wall contacts and duration time of wall contacts between the warm hands controls and exposed cold hands both conditions. However, changes were not statistically significant.
- Stress Physiology