Fig. 4.

Box plots of the threshold for each clinical sign for bipolar and monopolar cortical stimulation methods.

(a) The threshold for bipolar stimulation to induce a motor response was significantly lower than that for monopolar stimulation. * p < 0.05.

(b) The threshold for bipolar stimulation to induce a language response was significantly lower than that for monopolar stimulation. ** p < 0.0005.

(c) There was no significant difference between the thresholds required for bipolar and monopolar stimulation to induce a sensory response.