Transient acute depression induced by high-frequency deep-brain stimulation

STN vs. GPi Deep Brain Stimulation: Translating the Rematch into Clinical Practice

When formulating a deep brain stimulation (DBS) treatment plan for a patient with Parkinson's disease (PD), two critical questions should be addressed: 1- Which brain target should be chosen to optimize this patient's outcome? and 2- Should this patient's DBS operation be unilateral or bilateral? Over the past two decades, two targets have emerged as leading contenders for PD DBS; the subthalamic nucleus (STN) and the globus pallidus internus (GPi). While the GPi target does have a following, most centers have uniformly employed bilateral STN DBS for all Parkinson's disease cases (Figure 1). This bilateral STN "one-size-fits-all" approach was challenged by an editorial entitled "STN vs. GPi: The Rematch," which appeared in the Archives of Neurology in 2005. Since 2005, a series of well designed clinical trials and follow-up studies have addressed the question as to whether a more tailored approach to DBS therapy might improve overall outcomes. Such a tailored approach would include the options of targeting the GPi, or choosing a unilateral operation. The results of the STN vs. GPi 'rematch' studies support the conclusion that bilateral STN DBS may not be the best option for every Parkinson's disease surgical patient. Off period motor symptoms and tremor improve in both targets, and with either unilateral or bilateral stimulation. Advantages of the STN target include more medication reduction, less frequent battery changes, and a more favorable economic profile. Advantages of GPi include more robust dyskinesia suppression, easier programming, and greater flexibility in adjusting medications. In cases where unilateral stimulation is anticipated, the data favor GPi DBS. This review summarizes the accumulated evidence regarding the use of bilateral vs. unilateral DBS and the selection of STN vs. GPi DBS, including definite and possible advantages of different targets and approaches. Based on this evidence, a more patient-tailored, symptom specific approach will be proposed to optimize outcomes of PD DBS therapy. Finally, the importance of an interdisciplinary care team for screening and effective management of DBS patients will be reaffirmed. Interdisciplinary teams can facilitate the proposed patient-specific DBS treatment planning and provide a more thorough analysis of the risk-benefit ratio for each patient.

Update on deep brain stimulation

Deep brain stimulation (DBS) is an established therapy for movement disorders and an investigational treatment in other neurologic conditions and in neuropsychiatry. DBS can target with precision neuroanatomical targets deep within the brain that are proposed, on the basis of increasing evidence from functional neuroimaging and other methods, to be centrally involved in the pathophysiology of some neuropsychiatric illnesses. DBS is nonablative, offering the advantages of reversibility and adjustability. In theory, this characteristic might permit therapeutic effectiveness to be enhanced or side effects to be minimized. Although its mechanisms of action are unknown, several possible effects have been proposed to underlie the therapeutic effects of DBS in movement disorders, and potentially in other conditions as well. This issue is the subject of very active investigation in a number of clinical and preclinical laboratories. DBS may offer a degree of hope for patients with intractable neuropsychiatric illness. Research intended to realize this potential will require a very considerable commitment of resources, energy, and time across disciplines including psychiatry, neurosurgery, neurology, neuropsychology, and bioethics. Investigations in this area should proceed cautiously.