Subthalamic stimulation may inhibit the beneficial effects of levodopa on akinesia and gait.

BACKGROUND: Gait and akinesia deterioration in PD patients during the immediate postoperative period of DBS has been directly related to stimulation in the subthalamic region. The underlying mechanisms remain poorly understood. The aim of the present study was to clinically and anatomically describe this side effect. METHODS: PD patients presenting with a worsening of gait and/or akinesia following STN-DBS, that was reversible on stimulation arrest were included. The evaluation included (1) a Stand Walk Sit Test during a monopolar survey of each electrode in the on-drug condition; (2) a 5-condition test with the following conditions: off-drug/off-DBS, off-drug/on-best-compromise-DBS, on-drug/off-DBS, on-drug/on-best-compromise-DBS, and on-drug/on-worsening-DBS, which utilized the contact inducing the most prominent gait deterioration. The following scales were performed: UPDRSIII subscores, Stand Walk Sit Test, and dyskinesia and freezing of gait scales. Localization of contacts was performed using a coregistration method. RESULTS: Twelve of 17 patients underwent the complete evaluation. Stimulation of the most proximal contacts significantly slowed down the Stand Walk Sit Test. The on-drug/on-worsening-DBS condition compared with the on-drug/off-DBS condition worsened akinesia (P = 0.02), Stand Walk Sit Test (P = 0.001), freezing of gait (P = 0.02), and improved dyskinesias (P = 0.003). Compared with the off-drug/off-DBS condition, the on-drug/on-worsening-DBS condition improved rigidity (P = 0.007) and tremor (P = 0.007). Worsening contact sites were predominantly dorsal and anterior to the STN in the anterior zona incerta and Forel fields H2. CONCLUSIONS: A paradoxical deterioration of gait and akinesia is a rare side effect following STN-DBS. We propose that this may be related to misplaced contacts, and we discuss the pathophysiology and strategies to identify and manage this complication. © 2016 International Parkinson and Movement Disorder Society.

[Indications for anticoagulant use in secondary prevention of strokes]. / Indications des anticoagulants en prévention secondaire des accidents vasculaires cérébraux.

THE CONTEXT: The demonstration of the efficacy of oral anticoagulants in the secondary prevention of ischemic stroke represents a major progress in medicine in the last twenty years. Efficacy in fact depends on the causes and this determines the indications. ADMITTED AND DEMONSTRATED INDICATIONS: Cardiac arrhythmia due to atrial fibrillation and the existence of mechanical prosthetic valves are the only two indications that have been demonstrated with sufficient proof. ADMITTED NON-DEMONSTRATED INDICATIONS: These are basically the dissection of cervical arteries, aortal cross atheroma, vascular cerebral accidents within the context of antiphospholipid antibody syndromes. POSSIBLE INDICATIONS: There are three: stenosis of the intra-cranial arteries, patent foramen ovale with atrial septum aneurysm and the basilar dolichoectasia trunks. NON-DEMONSTRATED SUPERIORITY: In atherosclerosis-induced cerebral ischemic accidents.