Information Sheet This information sheet provides details for the procedure that you are considering, together with the risks and possible benefits of this procedure. Procedure The procedure that has been proposed is: Insertion of Medtronic PC&S Primary Cell Implanted Pulse Generator The device will provide deep brain stimulation and also enable measurement your seizure threshold (i.e., the point at which increasing stimulation risks causing a seizure). The device will be used to measure the level of stimulation that you are likely to be able to tolerate without a seizure. The procedure to remove the old battery and replace it with the new one will involve being given an anaesthetic. This may be a general anaesthetic, or alternatively some local anaesthetic will be given along with drugs to make you sleepy. The anaesthetist will discuss which is more suitable for you with you before surgery. Once this device is removed the new device will be inserted and connected to the leads that you already have in place. After the operation, you will spend up to five days in hospital. While you are in hospital the DBS team will work with you to identify the best settings for your new device. This will involve up to two programming/threshold finding sessions per day with a specialist nurse or Dr. Cheeran. Risks of Proceeding ACC DBS is a novel procedure. This IPG has not been used to measure seizure thresholds in humans before, although more than 50 have been implanted in patients with Parkinson's Disease for other reasons. There are a number of known risks, which are set out below. It is also possible that the procedure might result in complications that cannot be predicted (so called “unknown unknowns”). This means it is not possible to list all the possible risks. Only the known risks are listed here. Seizure following anaesthesia Recurrence of seizures despite stimulation below detected seizure threshold Device fails to assess seizure threshold Pneumonia: 0.4–0.6% Infection: 2.8–6.1% (if the IPG becomes infected the infection will be treated but the IPG will be removed and it will not be possible to replace it with another device) Skin erosion: 1.3–2% Death Risks of Not Proceeding Current IPG device remains switched off No possibility of pain relief from IPG No change in frequency of seizures No reduction in pain relieving medication Benefits of Proceeding Possibility of pain relief with associated improvement in quality of life and day to day functioning Improved monitoring of seizure threshold which may mean that seizures can be reduced Possibility of reducing dosage of pain relieving medication Benefits of Not Proceeding Avoid known risks of surgery Avoid “unknown” risks