The Effectiveness of Deep Brain Stimulation in Dystonia: A Patient-Centered Approach

BACKGROUND: To systematically evaluate the effectiveness of deep brain stimulation of the globus pallidus internus (GPi-DBS) in dystonia on pre-operatively set functional priorities in daily living. METHODS: Fifteen pediatric and adult dystonia patients (8 male; median age 32y, range 8–65) receiving GPi-DBS were recruited. All patients underwent a multidisciplinary evaluation before and 1-year post DBS implantation. The Canadian Occupational Performance Measure (COPM) first identified and then measured changes in functional priorities. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) was used to evaluate dystonia severity. RESULTS: Priorities in daily functioning substantially varied between patients but showed significant improvements on performance and satisfaction after DBS. Clinically significant COPM-score improvements were present in 7/8 motor responders, but also in 4/7 motor non-responders. DISCUSSION: The use of a patient-oriented approach to measure GPi-DBS effectiveness in dystonia provides an unique insight in patients’ priorities and demonstrates that tangible improvements can be achieved irrespective of motor response. HIGHLIGHTS: Functional priorities in life of dystonia patients and their caregivers vary greatly. The effect of DBS on functional priorities did not correlate with motor outcome. Half of the motor ‘non-responder’ patients reported important changes in their priorities. The effect of DBS in dystonia should not be measured by motor outcome alone.