Impedance and Phase Angle as a Locating Method in Human Stereotaxic Surgery

OBINSON et al. 6 have recently shown t h a t measuremen t of brain tissue impedance and phase angle by means of a roving electrode is a useful me thod in locat ing deep cerebral s t ructures in laborato ry animals. T h e y also recorded impedance and phase angle in the dead h u m a n brain. T h e y considered the method safe and useful for h u m a n stereotaxic use. Dur ing 1965, we recorded the impedance and phase angle of brain tissue in 65 pat ients undergoing stereotaxic surgery for various conditions. I n this paper we report our technique and discuss the results and value of this me thod as a locating aid in stereotaxic surgery.