a clinical method used to investigate the blood supply to the human brain. An electronic device called a rheograph is utilized in rheoencephalography. Electrodes are attached to the skin at certain points on the head and permit the device to measure continuously the electrical conductivity of the tissues of structures located between the electrodes. The indications of the rheograph are recorded on a moving sheet of paper in the form of a rheoencephalogram. All fluctuations of the blood flow in the vessels of the brain are accurately reflected, since the electrical conductivity of the blood and liquor of the brain is three to four times greater than the electrical conductivity of the other brain tissues. Pathological and functional changes in the blood supply to the brain are detected upon analyzing the rate of increase and the amplitude of pulse waves and also upon comparing rheoencephalograms recorded simultaneously from symmetrical sections of the brain.

Rheoencephalography does not disrupt brain activity and is harmless to the person being studied; for this reason, it is widely used to diagnose diseases of the brain’s vascular system.