Hundreds of studies since the 1990s have looked at how well deep brain stimulation works for patients with Parkinson's disease or essential tremor. OHSU has led dozens of these studies.

Most studies have found that DBS can be much more effective than medication to treat movement-related symptoms. On this page, you will find highlights of this research.

For Parkinson's patients

• Improved movement: One study found that patient motor scores improved 53% after two years with DBS, compared to improving 4% among patients taking medicine.¹
• Improved quality of life: The same study found a 26% improvement in quality-of-life scores among DBS patients, compared to a 1% decline in patients taking medicine.¹
• Fewer side effects and other benefits: The study also found that DBS helped patients score better on "activities of daily living.” Patients had fewer side effects since they took less medication. They also had more time with good mobility and no dyskinesia.¹
• More time with no symptoms: Another study showed that after DBS surgery targeting the brain’s subthalamic nucleus, the amount of awake time with no motor symptoms increased from 27% to 74%.²
• Again, more time with no symptoms: The same study found that after DBS surgery targeting the brain’s globus pallidus internus, the amount of awake time with no motor symptoms increased from 28% to 64%.²

For essential tremor patients

• Less tremor, improved hand function: A 2003 study found that DBS significantly improved tremor and hand function. Benefits were present six or seven years after surgery for most patients, with few side effects.³

Awake versus asleep DBS

In 2011, OHSU's Dr. Kim Burchiel was the first surgeon to do asleep DBS, with the patient under general anesthesia.

Benefits from asleep surgery: A 2017 OHSU study found that people who had asleep DBS had better outcomes six months later than people who had awake DBS. They also had higher scores in communication, speech and cognition (thinking) abilities. Both groups had similar improvements in motor symptoms, such as tremor.⁴

See details of the OHSU study.

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¹ Neurostimulation for Parkinson’s Disease with early motor complications, New England Journal of Medicine, 2013

² Deep-brain stimulation of the subthalamic nucleus or the pars interna of the globus pallidus in Parkinson's disease, New England Journal of Medicine, 2001

³ Long-term efficacy of thalamic deep brain stimulation for tremor: Double-blind assessments, Movement Disorders, 2002

⁴ Clinical outcomes of asleep vs awake deep brain stimulation for Parkinson disease, Neurology, 2017

⁵ Telemedicine and Deep brain stimulation – Current practices and recommendations, Parkinsonism & Related Disorders, 2021

⁶ Role of Directional Configuration in Deep Brain Stimulation for Essential Tremor: A Single Center Experience, Tremor and Other Hyperkinetic Movements, 2021