The subdural ECoG strip (HKHS), composed of eight stainless steel contacts of 4 mm total diameter, 2.5 mm exposed diameter and 10 mm spacing interval (except one subject was implanted with the 30 contact strip electrodes with 3 mm total diameter, 1.7 mm exposed diameter and 5 mm spacing) was placed in the right M1 region through the same burr hole as the DBS electrodes. Preoperative high-resolution CT with the stereotactic frame markers attached was computationally fused to the anatomical T1-weighted MRI, enabling stereotactic planning and confirmation that the distance between the burr hole and the M1 is within the range of the ECoG strip length. After surgery, the position of the ECoG strip was confirmed with a CT scan and 3D cortical surface reconstruction.20 The exemplary postoperative CT-MRI fused image and the surface reconstruction showing the position of the ECoG and DBS electrodes are displayed in Fig. 1A and B. ECoG strips were taken out at the second stage of DBS surgery when the pulse generator connected to DBS electrodes was implanted. The average duration of lead externalization was
