EEG activities with open eyes in a quiet state (OA), during the pseudo-Raven's test (PRA), in hypnagogic state (HYP) and in the course of REM sleep (REM) are characteristic by nearly flat curves. We observed the states with eyes closed (OC), with hyperventilation (HV), during mental activity of calculation (CAL) and in NONREM 1 sleep (NR 1). 24 tested persons (probands) were investigated. We have found 8 typical states of EEG signals, which all have relation to attention and mental activity. Consequently, the EEG analysis can help in the differentiation between the above eight states. Using similar analyses, it is possible to discriminate all stages of NONREM and REM sleep without polysomnography.