[Utilization of theta/alpha spectral range as an indicator of vigilance: pharmacological applications during repeated...

Three successive double-blind, cross-over vs placebo trials with amphetamine 10 mg, amineptine 200 mg, clonidine 150 mcg were made in 12 x 3 healthy volunteers by means of a multiple sleep latency test (MSLT) associated with quantitative EEG. Data were evaluated by a 3-way ANOVA for repeated measurement. The aim of the study was to find out the most efficient parameters from theta/alpha ratio to exhibit a "time effect", i.e. the physiological variation of vigilance during the daytime and a "drug effect", i.e. a stimulant or sedative effect. The best parameter was the difference between the maximum and the minimum values of the theta/alpha ratio during the recording session. The time after which the theta/alpha doubled and the time after which the subject was the most relaxed (theta/alpha minimum) exhibited significant variations due to time effect and only sedative drug effect. The results of the other classical parameters from MSLT, visual analogue scales and sleep questionnaires were discussed as was the use of parameters from quantified EEG in order to make up homogeneous groups of healthy volunteers.