The effects of slow waves in the screening EEGs of pilot cadets on P300 ERP and memory scanning performance.

ABSTRACT

BACKGROUND: Electroencephalography (EEG) screening of pilot candidates has long been established but remains controversial. The EEG records of 0-15% of the test population demonstrate the presence of brief periods of slow waves (theta, 4-7.9 Hz and delta, 0-3.9 Hz). The significance of these EEG findings for pilot selection has not been defined. HYPOTHESIS: We investigated whether the existence of slow waves in the EEG records of cadet pilots was related to differences in their cognitive performance. If so, the EEG could serve as a tool for cognitive assessment in candidate pilot screening. The relationship between spontaneous EEG slowing and cognitive performance has not been investigated although there is evidence of EEG slowing during the performance of short-term memory tasks. METHODS: Some 116 screening EEG records were re-evaluated for the presence of slow wave activity. Cadets with positive records and a control group performed a) a modified version of Sternberg's visual memory scanning task on a PC computer; and b) the auditory "OddBall" behavioral task for eliciting the P300 evoked response using the Nicolet Spirit Evoked Potential System. RESULTS: Analysis of the behavioral and electrophysiological data was divided in EEG groups a) Normal; b) Bilateral slowing only during hyperventilation; c) Bilateral slowing; d) Slowing with right dominance; and e) Slowing with left dominance, showed no significant difference among the groups for all parameters measured. CONCLUSIONS: Brief periods of bilateral or focal EEG slow activity in the records of pilot cadets could not predict differences in cognitive function as this was assessed in these experiments. Specific neuropsychological screening procedures might be more valuable for this purpose than the standard EEG screening.