A multi-center study to investigate the utility of biosignals recorded during deep brain stimulation.

All participants who are undergoing clinically indicated deep brain stimulation (DBS) surgery for implantation or revision purposes will have biosignals recorded during surgery. Biosignals will be measured from DBS electrodes using a custom-made neurostimulator and recording system. Connection to participants will use a one-time-use sterilised cable provided as standard-of-care and two disposable patch electrodes attached to skin below the shoulders. The customised device will be operated by a highly trained researcher. Collection of biosignals will take an additional 15-20 minutes throughout surgery where a surgery routinely takes 3-4 hours, although this can vary between treating teams. Stimulation is delivered in short 10 second bursts using similar parameters to those used for standard-of-care chronic therapy; balanced biphasic pulses with frequency less than 400 Hz and amplitude less than 9 milliamperes (typically 3.3 mA). DBS surgery will otherwise proceed as per standard of care which includes placing the participant under local or general anaesthetic, implantation of DBS leads into specific brain targets by the neurosurgeon, and performing intra operative imaging (CT scan) to confirm the location of DBS leads, or post DBS surgery if a CT scanner is not available in theatre. X-rays of the head are also performed during DBS surgery to confirm DBS leads location As part of standard of care prior to and after surgery, medical imaging (MRI brain, CT brain) is collected for surgical planning and to confirm DBS electrode location/orientation. The pre-operative MRI brain scan prior to surgery takes an average of one hour, and the post operative CT scan takes an average of 15 minutes. Participants will be recruited into one of two study arms: Arm 1: Participants will exit the study following 7 days of observation after DBS surgery. Arm 2: Participants will be supported through initial DBS programming sessions as per standard of care, with the initial program guided by biosignal data. Participants will continue to be observed for an additional 4 months and undergo standard of care assessments before exiting the study. This study intends to enrol 300 participants in total (200 for Arm 1 and 100 for Arm 2). There is no randomisation or pre-determined pattern to recruit participants into any given arm or sub-study. Once the required sample size for Arm 2 is reached, all subsequent participants will be recruited into Arm 1. Relevant standard of care assessments, e.g. participant outcome measures and chronic DBS settings, may also be accessed from participant medical records up to 18 months post screening. A group of participants in either Arm 1 or 2 may be invited into a sub-study where additional DBS programming testing will occur over two days at most. Participants are eligible for the sub-study if they have been diagnosed with Parkinson's disease and have not had any complications from the DBS surgery (such as a malpositioned electrode) or any other issues which, in the opinion of the investigators, might compromise the participant’s ability to complete the protocol. The sub study will occur 4 months post surgery. During these sessions, DBS programs will be temporarily changed by a movement disorder clinician and their symptoms assessed using routine assessment tools. At the conclusion of each session, participant's DBS program will be returned back to their usual DBS program. Each session will take approximately 4 to 5 hours.