Operator's Reaction Time Prolongation Induced by Whole-Body Vibration

Influence of whole-body vibration on reaction times was studied on a specially developed rig, with the subjects being exposed to no vibration, and vibration frequencies of 1, 5, 20 and 50 Hz. The shortest reaction times for both, sound and visual stimuli were measured for no vibration of the seating platform. The most detrimental influence was observed at vibration frequency of 5 Hz, with reaction times typically increasing between 50 and 70 ms. The shortest reaction times were always measured at the beginning of tests and the longest at the end. The increases in reaction times with elapsed time were typically more pronounced when subjects were exposed to sound stimuli. Equally, under the same conditions, reaction times to sound stimuli were longer than to visual stimuli (by approx. 60 to 100 ms). In all cases, changes in standard deviation values follow the same pattern as average reaction times.