DBS electrodes were placed in the bilateral STN as previously reported.19 Briefly, DBS electrodes (model L301, Pins Medical) were implanted into the T2-weighted MRI identified STN target using a Leksell stereotactic system (Elekta Instrument AB) under local anaesthesia. Intraoperative microelectrode recording measuring the length of the DBS trajectory in the STN and macro-stimulation tests were conducted for trajectory selection. A CT scan was performed to confirm the location of the lead and to look for any signs of cerebral haemorrhage after surgery.
