Study Suggests Deep Brain Stimulation Does Not Increase Risk of Dementia in Patients With Parkinson Disease

In patients with Parkinson disease (PD) who underwent deep brain stimulation (DBS), dementia prevalence and incidence were not found to be higher than those in the general PD population, according to study findings published in Neurology.

The benefit derived from DBS of the subthalamic nucleus (STN) has been shown to be more effective than medication in managing movement issues. Moreover, a prior study indicated its potential in slowing the progression of early-stage PD.

While promising, the invasive nature of the procedure, which involves the implantation of electrodes placed in certain areas of the brain that control electrical impulses, may not appeal to all patients. Additionally, research has been mixed on whether STN-DBS can increase the risk of developing dementia, a factor that researchers sought to further examine.

Researchers conducted a retrospective study to evaluate the presence and potential risk factors for postoperative dementia at short-, medium-, and long-term (1, 5, and 10 years, respectively) follow-up dates after STN-DBS. The study recruited 175 people with PD with an average age of 56 years who underwent STN-DBS, of whom 104 were available at 10-year follow-up. Participants had PD for an average of 12 years when they underwent the procedure.

In the study findings, dementia prevalence was reported as 2.3% at 1 year, 8.5% at 5 years, and 29.8% at 10 years, amounting to an overall incidence rate of 35.6 per 1000 person-years. Among the study cohort, male sex, higher age, hallucinations, lower frontal score at baseline, and perioperative cerebral hemorrhage were all indicated as predictors of dementia.

Study author Elena Moro, MD, fellow of the American Academy of Neurology, highlighted that these rates are not higher than those in the general population of people with PD and that other studies with similar disease duration have reported even higher rates of dementia. “Other studies of people with PD who are taking medication for their symptoms show an incidence rate for dementia that varies from 50 to 100 per 1000 person-years," expanded Moro.

Notably, Moro notes that the study cohort’s younger average age may explain the lower rate of dementia. The high percentage of people who did not finish the 10-year follow-up may also represent a study limitation.

However, Moro highlighted the significance of predictors found in the study, which can assist physicians in selecting people who would best respond to STN-DBS and those who may be at greater risk of developing dementia.

"These results are very encouraging for people with PD and their families that they can take advantage of the benefits of deep brain stimulation without worrying about it increasing the likelihood of developing dementia," said Moro.

Reference

Bove F, Fraix V, Cavallieri F, et al. Dementia and subthalamic deep brain stimulation in Parkinson disease. Neurology. Published online July 1, 2020. doi:10.1212/WNL.0000000000009822