Deep brain stimulation outcomes in the malignant end of Parkinson's disease spectrum

Background: Heterogeneity of Parkinson's Disease (PD) phenotype may influence deep brain stimulation (DBS) outcome. However, DBS response in the malignant end of the PD spectrum has been poorly investigated. Objective: To evaluate and compare DBS outcomes in malignant and benign PD patients, defined according to motor and non-motor symptom presentation at the presurgical selection. Methods: We categorized a cohort of 154 parkinsonian patients fulfilling criteria for subthalamic nucleus (STN)DBS into malignant, benign, and intermediate subtypes, according to a recently validated clinical PD classification. DBS efficacy on daily living independence (Schwab and England -S&E-score >= 70%), motor symptoms, and motor fluctuations (Unified Parkinson's Disease Rating Scale -UPDRS- part-III and -IV, and Ambulatory Capacity Measure) were compared between malignant and benign patients, using corrected binary logistic regressions and repeated measure general linear model. Results: One year after surgery, the probability of losing daily life independence was 16-fold higher in malignant patients, even after adjusting for age at PD onset, PD duration, and percentage of motor improvement after STNDBS (OR: 16.233; p: 0.035). Conversely, malignant and benign patients showed a similar extent of improvement after STN-DBS (p > 0.05) in motor symptoms, motor fluctuations, and ambulatory capacity, both in medicationON and medication-OFF conditions. Conclusion: DBS candidates in the malignant end of the PD spectrum may profit from a similar improvement of motor symptoms and fluctuations after STN-DBS when compared to benign PD. However, patients of the malignant group have a lower probability of maintaining independence in daily life early after surgery.

Automated summary

In patients with Parkinson's Disease, those at the malignant end of the spectrum have a higher risk of losing independence in daily living after DBS surgery compared to benign patients, despite similar improvements in motor symptoms and fluctuations.