Multifrequency REG: Fundamental Background, Informational Meaning and Ways of Data Analysis and Automation

A long historical experience of monofrequency rheoencephalography (REG) showed its limited capabilities. The new approach ispresented – multifrequency REG that is REG recording simultaneously at three frequencies - 16, 100 and 200 kHz. The different brain impedances received were analysed on the base of equivalent electrical circuits of brain tissue. First, this enables to calculate intra-extracellular electrical component for evaluation of brain tissue hydration state by means of an original computational method. Second, dynamic cooperative analysis of multi-REG and transcranial Doppler pulsations provides the indices of intracranial CSF mobility (CSFm) and cranial compliance (CCe). Third, spectral analysis of processes recorded provides valuable information of regulatory processes involved. The application of this new approach to investigation of intracranial circulation in healthy persons of different aging groupos and in neurosurgical patients showed its promising effectivity.