Electric and metabolic brain activities were controlled for 49 persons by means of electroencephalography (EEG) and near infrared spectroscopy (NIRS) during different physiological and psychological states, e.g. eyes open or closed, hyperpnoea (HV) or apnoea (AP) and during calculation (addition of one- (CAL.S.) or two-digit numbers (CAL C.)) or Raven's test - set A (RAV A) or more difficult set C (RAV C) or TAT. Both diagnostic methods confirm one another. But sometimes there are more expressive changes in one method than in another, e.g. during HV it is a more prominent deoxyhemoglobin (CO2Hb) increase than an alpha frequency band increase in EEG curves. On the other side, very marked alpha frequency decreasing in EEG during eyes open is followed by only a weak oxyhemoglobin (O2Hb) rise. Synchronous activities are clearly visible during psychic test: increasing O2Hb in NIRS and increasing delta frequency band in EEG spectrum. Decreasing alpha with increasing theta activity during relaxation and somnolence is accompanied by decreasing O2Hb and prominent increasing CO2Hb. Inter individually differences are often but not big. We suggest both methods are good tools for attention and psychic states control.
In this paper, an extended analysis of the human electroencephalographic signals (EEG) in the region of alpha rhythms is presented. The consequences of the existence of spindle-like (fusiform) shape are discussed and verified on the set of experimental measurements. The hypothesis of possible interrelations of the EEG alpha fuses with a tested person's psychical state and restrictions is presented.