Workload and fatigue--in-flight EEG changes.

Continuous recordings were made of the EEG and ECG of one pilot during a series of instrument flights in a feeder-type transport aircraft. The flights were arranged to contain epochs of distinctly differing levels of workload. In addition, some flights were made after a night of sleep deprivation and others were made as the second and third flights of the day. Subjectively, there appeared to be marked differences in performance between the two types of tired flight. The EEG analyses showed changes that correlated well with differences in workload. In the highest workload areas during fresh flights, EEG activity increased by approximately a factor of 4 over that of the preflight resting values. This large increase did not occur in the tired flights. Further experiments are planned using flights in aircraft and in simulators using several subjects.