‘Self-tuning’ brain implant could treat Parkinson’s disease

A study has described the first fully implanted deep brain stimulation (DBS) system that uses feedback from the brain itself to fine-tune its signalling, potentially leading to a treatment for patients with Parkinson’s disease.

The study, supported by researchers at the National Institutes of Health’s Brain Research through Advancing Innovative Technologies (BRAIN) Initiative and the National Institute of Neurological Disorders and Stroke (NINDS), builds on previous research into deep brain stimulation, which has been used to treat Parkinson’s disease symptoms for 25 years. The technique involves surgically implanting an electrode into the brain to deliver constant stimulation to a part of the brain – the basal ganglia – to treat the symptoms of the disease. This approach however can lead to unwanted side effects.

This new study describes a novel adaptive method whereby the stimulation delivered is responsive in real time to signals received from the patient’s brain. In a short-term feasibility trial, two patients with Parkinson’s received a fully implanted, adaptive deep brain stimulation device. The can both monitor and modulate brain activity. In this study, sensing was done from an electrode implanted over the primary motor cortex, a part of the brain critical for normal movement.

Signals from this electrode are then fed into a computer programme embedded in the device, which determines whether to stimulate the brain. For this study the researchers taught the programme to recognise a pattern of brain activity associated with dyskinesia, the uncontrolled movements that are a side effect of DBS in Parkinson’s disease, as a guide to tailor stimulation. Stimulation was reduced when it identified dyskinesia-related brain activity and increased when brain sensing indicated no dyskinesia to minimise deep brain stimulation-related side effects.

Dr Philip Starr, Ph.D., professor of neurological surgery, University of California, San Francisco, and senior author of the study, which was published in the Journal of Neural Engineering, said: “This is the first time a fully implanted device has been used for closed-loop, adaptive deep brain stimulation in human Parkinson’s disease patients.”

Nick B. Langhals, Ph.D., programme director at NINDS and team lead for the BRAIN Initiative, said: “The novel approach taken in this small-scale feasibility study may be an important first step in developing a more refined or personalised way for doctors to reduce the problems patients with Parkinson’s disease face every day.”

Dr Starr added: “Here we have demonstrated the feasibility of adaptive deep brain stimulation. We are now planning larger, longer-term trials to determine how effective this system is in managing the symptoms of patients with Parkinson’s disease.”