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January 1967

Inadequacy of "Rheoencephalography": A Clinical Study of Impedance Cephalography for Evaluation of Cerebrovascular Disorders

Author Affiliations

From the Section of Neurology, Cerebrovascular Clinical Research Center, Mayo Clinic and Mayo Foundation (Dr. Waltz); and Mayo Graduate School of Medicine, University of Minnesota (Dr. Ray), Rochester, Minn.

Arch Neurol. 1967;16(1):94-102. doi:10.1001/archneur.1967.00470190098012

A RELIABLE and sensitive technique for the simple and safe measurement, through the intact skull, of changes in the flow or circulation of blood in the human brain would be extremely useful for the diagnosis and management of cerebrovascular disorders. "Rheoencephalography," which we prefer to call "impedance cephalography," has been proposed as a method for the study of the cerebral circulation. Basically, impedance cephalography is the technique of impedance plethysmography, applied to the head. The impedance recorded from the head during the passage of an electric current changes with the cardiac cycle; the cyclic changes of impedance presumably are related in some way to the entrance of blood into the head.

Certain earlier reports1,2 on the use of impedance cephalography for the diagnosis of cerebrovascular disease indicated that the technique is of little value. These earlier studies have been criticized by proponents3 (R. Sano and R. Namon, personal