Abstract
BACKGROUND: The role of deep brain stimulation (DBS) in the management of motor symptoms in patients with Parkinson's disease is well defined. However, it is becoming increasingly clear that DBS can either improve or worsen a number of non-motor phenomena. OBJECTIVES: We examined the published literature to better understand the effects on autonomic symptoms following DBS of the subthalamic nucleus and the globus pallidus interna. METHODS: We conducted a PubMed search of studies regarding the effects of DBS on the autonomic system published from January 2001. We searched for the following terms and their combinations: Parkinson's disease, deep brain stimulation, subthalamic nucleus, globus pallidus interna, autonomic dysfunction. RESULTS: Most studies reported in the literature focus on DBS targeting the subthalamic nucleus, with particular emphasis on favorable outcomes regarding gastrointestinal function and bladder control. However, the emergence or worsening of autonomic symptoms in subgroups of patients has also been documented. More controversial is the effect of stimulation on the cardiovascular, pulmonary, and thermo-regulatory systems as well as sexual functioning. Data regarding the influence of DBS on the autonomic system when the target is the globus pallidus interna is less forthcoming, with target selection varying according to centre and clinical indication. CONCLUSIONS: DBS appears to affect the autonomic nervous system, with varying degrees of influence, which may or may not be clinically beneficial for the patient. A better understanding of these effects could help personalize stimulation for individual patients with autonomic disorders and/or avoid autonomic symptoms in susceptible patients.