Experimental study of the course of threshold current, voltage and electrode impedance during stepwise stimulation from the skin surface to the human cortex.

Background: Transcranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances.

Objective: Threshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the cerebral cortex.

Patients And Methods: Data of 10 patients (6f, 53 ± 11 years) were analyzed.