Chronic illness is perceived as a particular kind of event. The aim of this paper is to understand the personal, familial and professional difficulties experienced by patients in France who have a neurodegenerative disease and undergo cerebral implants. This paper is based on the assumption that a treatment using biotechnical techniques is a unique disruptive experience which redefines the patient's life. Thirty patients (13 women and 17 men) from two French hospitals were interviewed at different stages of their medical history. Despite the excellent overall outcome of neurosurgery in patients with Parkinson's disease, there is often a contrast between the improvement in motor disability and the patient's difficulty in returning to normal life. These results allow us to analyse the link between the neurosciences and the experience of chronic illness.