Parkinson's disease is a progressive neurological condition in which patients develop problems primarily with movements such as tremor, stiffness and slowness, but also a whole range of other functions such as sleep and memory. It is thought that around 127,000 people in the UK are suffering from the condition. Initially symptoms can be managed well with medication although these cannot cure the condition and some patients can develop disabling side effects. Neuromodulation is a new treatment for Parkinson's which, although not a cure, is an additional treatment option for patients alongside other treatments such as neurosurgery.