EEG and ECG changes during simulator operation reflect mental workload and vigilance.
BACKGROUND
Performing mission tasks in a simulator influences many neurophysiological measures. Quantitative assessments of electroencephalography (EEG) and electrocardiography (ECG) have made it possible to develop indicators of mental workload and to estimate relative physiological responses to cognitive requirements.


OBJECTIVE
To evaluate the effects of mental workload without actual physical risk, we studied the cortical and cardiovascular changes that occurred during simulated flight.


METHODS
There were 12 pilots (8 novices and 4 experts) who simulated a flight composed of 10 sequences that induced several different mental workload levels. EEG was recorded at 12 electrode sites during rest and flight sequences; ECG activity was also recorded. Subjective tests were used to evaluate anxiety and vigilance levels.


RESULTS
Theta band activity was lower during the two simulated flight rest sequences than during visual and instrument flight sequences at central, parietal, and occipital sites (p < 0.05). On the other hand, rest sequences resulted in higher beta (at the C4 site; p < 0.05) and gamma (at the central, parietal, and occipital sites; p < 0.05) power than active segments. The mean heart rate (HR) was not significantly different during any simulated flight sequence, but HR was lower for expert subjects than for novices. The subjective tests revealed no significant anxiety and high values for vigilance levels before and during flight.


CONCLUSIONS
The different flight sequences performed on the simulator resulted in electrophysiological changes that expressed variations in mental workload. These results corroborate those found during study of real flights, particularly during sequences requiring the heaviest mental workload.
Dussault
Caroline
C
Institut de Medecine Aérospatiale du Service de Santé des Armées, Brétigny-sur-Orge Cedex, France. cdussault@imassa.fr
Jouanin
Jean-Claude
JC
Philippe
Matthieu
M
Guezennec
Charles-Yannick
CY
D000337:Aerospace Medicine; D003071:Cognition; D004562:Electrocardiography; D004569:Electroencephalography; D004594:Electrophysiology; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D018474:Weightlessness Simulation; D016526:Workload