Only physical aspects of quality of life are significantly improved by bilateral subthalamic stimulation in Parkinson's disease

Background The well known global improvement of quality of life (QoL) after bilateral high frequency chronic deep brain stimulation of the subthalamic nucleus (STN DBS) in Parkinson's disease (PD) is in contrast to behavioral disturbances as observed after surgery. Indeed the impact of DBS on physical versus mental aspects of QoL in PD remains unknown. Objective To assess the influence of bilateral STN DBS on physical versus mental aspects of QoL in Parkinson's disease. Methods The results of 27 patients for the Unified Parkinson s disease Rating Scale (UPDRS), Parkinson's Disease Questionnaire 39 (PDQ39) and Short Form 36 health survey questionnaire (SF36) were compared before surgery and after 12 months of bilateral STN DBS. Results Comparing off-dopa conditions before versus 12 months after surgery, both UPDRS part II and part III significantly improved: 32.6 % and 52 %, respectively. UPDRS part I scores did not change significantly at 12 months. As for PDQ39, the global score significantly improved after surgery (21.1 %) as did four subscores: mobility (25.6 %), activity of daily living (34.5 %), stigma (40.1 %) and bodily discomfort (30 %). Three PDQ39 subscores, however, showed no significant changes: emotional well-being (10.7 %), social support (3.2 %) and cognition (8.5 %) and one item even worsened: communication (-7.7 %). In SF36, only physical items significantly improved. Conclusion Using clinician's based rating scale, bilateral STN DBS showed significant improvement in PD patients at 12 month follow up. However, using patient's self-assessment scales, the clinical benefit of STN DBS was more subtle: physical items of QoL significantly improved, whereas mental items such as emotional well-being, social support, cognition and communication showed no improvement. Our results are suggestive of a dissociation of motor and non-motor symptoms control after bilateral STN DBS in PD patients.