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Deep Brain Stimulation Shows Long-Term Benefit in Parkinson’s Disease

Patients with Parkinson's disease appear to receive long-term benefit from deep brain stimulation (DBS), researchers reported at the 2021 virtual AAN Annual Meeting.

DBS that targeted the subthalamic nucleus or the globus pallidus interna continued to work for at least 10 years, reported Jill L. Ostrem, MD, FAAN, the Carlin & Ellen Wiegner endowed professor of neurology and division chief of the Movement Disorders and Neuromodulation Center at the Weill Institute for Neurosciences at the University of California, San Francisco.

“This study demonstrates continued motor benefit, reduced need for medications, and less motor fluctuations from both subthalamic nucleus and globus pallidus interna DBS after 10 years of DBS for Parkinson's disease," Dr. Ostrem told Neurology Today At the Meetings.

“DBS therapy had a significant and stable effect on motor function regardless of target over 10 years," she reported. “This is remarkable, given that Parkinson's disease is a progressive neurodegenerative disease. This is the longest follow-up describing DBS outcomes comparing the two targets in a randomized cohort."

Dr. Ostrem noted that there are no published studies from prospective randomized trials that compare DBS outcomes for the two targets—the subthalamic nucleus to the globus pallidus interna—beyond three years. She and colleagues assessed outcomes among 155 patients who were followed for 10 years after receiving DBS in either of the target positions.

Among patients who underwent DBS targeted to the globus pallidus interna, 85 patients were evaluated at two years, 68 patients at seven years, and 49 patients after 10 years. At baseline, they had a score of 43.2 on the Unified Parkinson's Disease Rating Scale (UPDRS). Their scores declined to 25.8 at two years, 35.4 at seven years, and 34 at 10 years.

Among those who underwent subthalamic nucleus target placement, 70 patients were evaluated at two years, 49 patients at seven years, and 29 patients at 10 years. Their baseline score UPDRS was also 43.2, but the score declined to 27.7 at two years, 34.4 at seven years, and 28.3 at 10 years.

Dr. Ostrem said that in a direct comparison there was a trend to better outcomes with subthalamic nucleus targeting, but that difference failed to achieve statistical significance (p=0.09). The primary outcome was a change in the motor subscale in the off medication/on stimulation state between targets and included multiple secondary outcomes.

While the motor symptoms did not appear to deteriorate greatly after DBS,  Dr. Ostrem pointed out that “non-motor symptoms continued to progress and are not as DBS-responsive, contributing to increased disability over time." 

Dr. Ostrem reported that bradykinesia subscores showed greater improvement at seven and 10 years with the subthalamic nucleus target than with the globus pallidus interna target (p=0.03).

She also pointed out that the UPDRS I, II, and IV scores and quality of time based on motor diaries also showed significant long-term improvement regardless of target. The total score on the quality of life test PDQ39 no longer showed improvement at seven or 10 years for either target. Lastly, both targets had significant medication reduction with no target difference over time (p=0.70)

Commenting on the study, Ritesh Ramdhani, MD, director of the DBS program at Northwell Health's Institute for Neurology and Neurosurgery in Manhasset, NY, said: “We had expected that DBS would have a sustained benefit long-term and I think that this study provides further support of that. We had no data to support that before, however, with both targets. So now we see pretty much equivalent outcomes for both globus pallidus interna and subthalamic nucleus targets."

Dr. Ramdhani noted that while the treatment had clinically meaningful reductions in tremor, Parkinson's disease remains a progressive illness. “Some of the motor symptoms that are not always helped with DBS are speech issues, gait and balance, and postural changes," he said. “With respect to the non-motor symptoms, they would include sleep disorders, constipation, and cognitive impairment."

He also noted that in the study group, bradykinesia scores—an assessment of limb slowness—also remained responsive.

Dr. Ostrem disclosed receiving personal compensation for consulting for Medtronic and Abbott. Dr. Ramdhani reported no disclosures.

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AAN Abstract S8.003: Ostrem J, Luo P, Weaver F, et al. 10 year clinical outcomes of subthalamic nucleus versus pallidal deep brain stimulation for Parkinson's disease: VA/NINDS CSP #468F.