Table 2 Overall risks of the study across various categories

Risks of DBS surgery and Implantation of Pulse Generator

Intracerebral hemorrhage; infection abscess; meningitis; misplacement of leads requiring revisions; post-operative displacement of leads; reaction to lead materials; hypodensity with mass effect around lead; intracranial extra-axial hemorrhage; stroke; pain at site of surgery; migration of leads; erosion of skin over hardware; hardware problems, such as abnormal impedances; hydrocephalus; seizures/epilepsy; cerebrospinal fluid leak; seroma; collection formation; pneumothorax/hemothorax/pleural effusions due to IPG; injury along the tunneling trajectory in the region of head, neck or chest; risks related to anesthesia (severe injury, cognitive decline, and death)

Risks Pertaining to Hardware Maintenance

Migration; infection; hardware malfunction/break; insulation problems; leaks of electricity; reaction to implants; erosion; incompatibility with MRIs; incompatibility with surgical equipment, medical devices or diagnostic devices

Risks due to stimulation and conduct of the experiment

Stroke/brain hemorrhage; dizziness; dyspraxia, dystonia, facial and limb muscle weakness, abnormal voluntary movements; numbness; attention, memory or language processing difficulties; suicide ideation and imminent risk of suicide (based on MADRS’ item 10, CSSRS’ item 5, BDI’s item 9 and behavioral interview); hypomania or motor contractions; any other unanticipated neurological deficits; worsening of chronic pain condition; behavioral or cognitive changes; rebound of symptoms when stimulation is stopped; visual field defects or eye movement disorders; headache; abnormal thinking; behavioral or psychiatric problems; changes in sexual function; disorders of consciousness; cardiovascular or respiratory events; electromagnetic interference; MRI may damage implantable devices

Risks Involved with Imaging

MRI may cause lesion to region targeted by DBS; fatigue and discomfort associated with nociceptive stimuli