Slow oscillations of psychophysiological parameters in human operators during monotony

Objective estimation of the human operator's functional state is an urgent problem in applied psychophysiology. It helps to forecast the reliability and efficiency of the operator's activity. Slow (minute) changes in the functional state of 22 subjects were recorded and analysed in experiments simulating the long-term operator's activity. Spatial synchronization of the electroencephalogram (EEG) and the heart-rate (HR) served as parameters. It was shown that the time of detection and identification of visual signals (geometrical figures) amid visual "noise" in a long-term observation naturally depends on the changes in a subject's state. These changes were estimated by slow (2-3 min) components of the changes in spatial synchronization of EEG and HR throughout 3 h of the experiment. These objective parameters of the human operator's state may be used to predict efficiency. The connection between minute oscillations of electrophysiological parameters and time of reaction is absent during the first 30 min of the experiment, then appears and increases throughout further stages, becoming clearly marked in its second half.