Predictors of cognitive and psychosocial outcome after STN DBS in Parkinson's Disease
- 1Department of Neurology of the Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- 2Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
- 3Department of Neurosurgery of the Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Correspondence to Ben Schmand, Department of Neurology, H2-222, Academic Medical Center, PO Box 22660, Amsterdam 1100 DD, The Netherlands;
- Received 19 November 2007
- Revised 16 January 2009
- Accepted 16 April 2009
- Published Online First 21 May 2009
Objective To find predictors of cognitive decline and quality of life 1 year after bilateral subthalamic nucleus deep brain stimulation (STN DBS) in Parkinson's disease (PD).
Methods A total of 105 patients were evaluated with a comprehensive neuropsychological assessment before and 12 months after surgery. A control group of 40 PD patients was included to control for effects of repeated testing and disease progression. The authors determined individual changes in cognition, mood and quality of life using a statistical method that controls for multiple comparisons, and performed logistic regression analyses to assess predictors of cognitive changes and quality of life.
Results 12 months after surgery, the improvement in motor function was 41% (Unified Parkinson's Disease Rating Scale Part 3 score in off). The STN group showed a large improvement in quality of life compared with the control group (Cohen d=0.9). At the individual level, 32% (95% CI 22 to 40) of the STN group showed a substantial improvement in quality of life. 36% (95% CI 27 to 46) of the STN patients showed a profile of cognitive decline compared with the control group. Mood improved in 16 STN patients and declined in 16 subjects. Impaired attention, advanced age and a low l-dopa response at baseline predicted cognitive decline, whereas a high l-dopa response at baseline predicted an improvement in quality of life. Postoperative decrease in dopaminergic medication was not related to cognitive decline.
Conclusions STN DBS improves quality of life. However, a profile of cognitive decline can be found in a significant number of patients. l-dopa response, age and attention at baseline are predictors of cognitive and psychosocial outcome.
- Parkinson's disease
- deep brain stimulation
- subthalamic nucleus
- quality of life
- stereotaxic surgery
Funding The study was supported by a grant from the Prinses Beatrix Fonds and the Parkinson Patiëntenvereniging.
Competing interests JDS acts as an independent consultant for Medtronic Ltd (Minneapolis). The movement disorders group of the AMC has received an unrestricted research grant from Medtronic Ltd.
Ethics approval Ethics approval was provided by the Medisch Ethische Toetsingscommissie, Academisch Medisch Centrum, Amsterdam.
Provenance and peer review Not commissioned; externally peer reviewed.