Computerized brain impedograph.

Abstract

Design of an on-line system utilizing a minicomputer and a specific dedicated hardware for 2T brain tissue impedance is provided. The prototype system, which can operate from 2 Hz to 10 kHz, covers most of the frequency range of interest in the encephalographic research. Driving the brain tissue with constant current and sampling the response current and voltage, the coefficients for a Fourier series expansion can easily be obtained. Real (resistance) and imaginary (capacitance) impedance components at each chosen frequency are printed on a Teletype printer.