Long-Term Neuropsychological Outcomes of Staged Subthalamic Nuclei Stimulation in Patients with Parkinson's Disease (P02.232)

Abstract

Objective: To assess cognitive functioning in patients with Parkinson9s disease (PD) following unilateral and subsequent contralateral deep brain stimulation of the subthalamic nucleus (STN-DBS). Background Bilateral STN-DBS is associated with mild decline in executive functioning. Staged surgery may be able to reduce such changes. However, there is little research on the cognitive effects of staged surgery. The present study examined cognitive functioning in PD patients before and after unilateral and subsequent contralateral STN-DBS. Design/Methods: We evaluated 16 consecutive PD patients (9 men, 7 women; mean age 67.4 ± 9.9) with the Mattis Dementia Rating Scale (MDRS), Rey Auditory and Verbal Learning Test (RAVLT), Controlled Oral Word Association (COWA; FAS), Digit Ordering Test, Symbol Digit Modalities Test (SDMT), Raven9s Progressive Matrices (modified), and Montgomery and Asberg Depression Rating Scale. Subjects were evaluated before the first surgery, about 8 months after the first surgery, and about 3.5 years after the second surgery. Differences between baseline and follow-up were assessed with repeated measures ANOVA. Results: Mean MDRS total score declined from 136.4 ± 2.0 at baseline, to 134.8 ± 2.4 after the first surgery, and to 129.5 ± 4.0 after the second surgery (p=0.02). Of the MDRS subscales, Initiation/Perseveration was the only scale to decline over time (p=0.02). There was decline for both letter fluency (p=0.0005) and category fluency (p=0.003). The SDMT raw score also showed decline (p=0.005). There were no significant changes for Digit Ordering Test, delayed memory, conceptual reasoning, or depression. Conclusions: Staged STN-DBS is associated with mild decline in overall level of functioning, fluency, and some aspects of executive functioning, similar to simultaneous bilateral surgery. However, since the second follow-up assessment occurred approximately 6 years after the baseline assessment, the observed decline may not be different from the natural progression of the disease. These results suggest that staged STN-DBS does not reduce frontal/striatal executive changes. Disclosure: Dr. Bernard has nothing to disclose. Dr. Stebbins has received personal compensation for activities with Impax Laboratories, Inc., Ceregene, Inc., Biovail Technologies, Ltd., Santhera Pharmaceuticals, and Ingenix Pharmaceutical Services. Dr. Stebbins has received research support from the National Institutes of Health, American Cancer Society, the Michael J. Fox Foundation, and Fragile-X Foundation. Dr. Bakay has received personal compensation for activities with Bayer/Schering for serving on their Safety Monitoring Board. Dr. Bakay has received research support from Ceregene, Inc., Medtronic, ANS and NIH. Dr. Verhagen has received personal compensation for activities with Medtronic, Inc., and Impax. Dr. Verhagen has received research support from Medtronic, Inc., ANS/St. Jude, Ceregene, Impax, Bayer-Schering, National Institutes of Health, and the Michael J Fox Foundation.