Reflection of mental exercise in the dynamic quantitative topographical EEG

Abstract

The aim of this study was to investigate the activation process of the central nervous system during mental demand in a complex psychophysiological situation. A 17-channel quantitative topographical EEG was recorded in 48 healthy volunteers (male and female, aged 49 +/- 6 years), using the CATEEM system, during four different psychometric tests (simple reaction time measurement, concentration performance, figure detection and word recall test). The mental load varied with each test, producing a graduated increase in spectral power density in delta and theta frequency range on the EEG in the fronto-temporal, parietal and occipital regions of the cortex and a generalized decrease in alpha power. During the rest periods after each test a graduated increase in alpha 1 power was seen as a possible expression of change in vigilance level. With this method we were able to differentiate two effects of psychometric tests on brain activity: the actual mental demand itself and the influence on the vigilance level.