By stimulating the brains of Parkinson's patients using electrodes, neurologists at France's CHU Saint-Étienne University Hospital found that this surgical technique could improve motor performance by 70% and reduce medication-based treatment by 40 to 60%.

When medication is no longer sufficient to control tremors, deep brain stimulation is a new alternative available to patients suffering from Parkinson's disease.

Practiced since May 2015 at France's CHU Saint-Étienne University Hospital, the technique appears to have proven results. Successfully operated patients saw motor performance improve by 70% and medication-based treatments reduce by 40 to 60%. The benefits of the operation were also found to remain for at least five years, with clear effects on patients' quality of life.

The operation is carried out under general anesthetic. It involves inserting two temporary electrodes into a patient's brain through a tiny opening in the cranium, targeting the subthalamic nucleus, which plays a major role in controlling movement. Small doses of electrical current are then delivered via the electrodes, which are connected to a unit placed under the skin to monitor effectiveness and unwanted side effects.

At the end of the operation, a definitive set of electrodes is implanted at sites found to give the best results in terms of treatment and side effects. Patients then remain in hospital for seven to ten days to fine-tune the stimulation system and adjust medication doses in relation to their needs.

Deep brain stimulation is generally offered after seven to eight years of disease progression, when patients reach advanced stages of the disease with motor fluctuations during the day.

This technique can be used to treat Parkinson's disease, tremors, obsessive compulsive disorders and dystonia.

Parkinson's disease is a degenerative disorder of the central nervous system characterized by the destruction of neurons that produce dopamine. It mainly affects the motor system, with effects including slowness of movement, rigidity -- which is often asymmetrical -- and a resting tremor. Patients can also present a multitude of other symptoms (anxiety, depression, pain, etc.).

Current treatments for Parkinson's disease can partially control motor symptoms but have no effect on other symptoms or on the disease's progression and degenerative nature.