Papers by François Alesch
Brain stimulation
Freezing of gait (FOG) is a specific gait disorder in Parkinson's Disease (PD). FOG occurs mainly... more Freezing of gait (FOG) is a specific gait disorder in Parkinson's Disease (PD). FOG occurs mainly in the medication-off state and usually improves with dopaminergic medication. FOG episodes can be clinically grouped into three patterns (small steps forward, trembling in place, complete akinesia) and five provoking subtypes (starting to walk hesitation, moving in tight quarters hesitation, reaching destination hesitation, turning hesitation, and walking in open space hesitation) [1]. FOG is a debilitating symptom, limiting activities of daily living, leading to falls or fall-related injuries, and diminishing quality of life [2]. The effect of deep brain stimulation of the subthalamic nucleus (STN-DBS) on freezing of gait (FOG) remains under debate since the prior results were conflicting. Whereas some studies [3,4] found an overall reduction of FOG under STN-DBS (although in most cases not to the same extent as non-axial symptoms), others reported no effect or even a deterioration of FOG [5e7]. The aim of this study was to evaluate the effect of STN-DBS on FOG with a special focus on the different FOG subtypes and patterns, as observed during a FOG provoking walking test performed before and at three follow ups after implantation. The VANTAGE study [8] e a multicenter, prospective, openlabel, non-randomized trial e assessed the effect of an implantable DBS system (Vercise™, Boston Scientific, Valencia, CA, USA) for bilateral stimulation of the STN in subjects with moderate to severe PD. In this preplanned sub-study, FOG was evaluated both subjectively (FOG questionnaire (FOGQ), the PDQ-39 mobility items, and FOG-specific items of the UPDRS II (items 13 [falls] and 14 [freezing])) and objectively with a standardized walking test provoking FOG (adapted from Ref. [1]). It was performed at baseline and at weeks 12, 26, and 52 postoperatively in the medication-on and-off state. STN-DBS was activated at all follow ups. The walking test was videotaped and made available for offline analysis by an independent and fully blinded rater (CB), who was unaware of the
World neurosurgery, Jan 9, 2016
Deep brain stimulation (DBS) within or adjacent to the subthalamic nucleus (STN) currently repres... more Deep brain stimulation (DBS) within or adjacent to the subthalamic nucleus (STN) currently represents the most common stereotactic procedure performed for Parkinson's disease. Better STN imaging is often regarded as a requirement for improving stereotactic targeting. But, remarkably enough, it is unclear whether there is a consensus about the optimal target. To obtain an expert opinion on the site regarded optimal for 'STN stimulation', movement disorder specialists were asked to indicate their preferred position for an active contact on hardcopies of the Schaltenbrand and Wahren atlas depicting the STN in all three planes. This represented an idealized setting and it mimicked optimal imaging for direct target definition in a perfectly delineated STN. The suggested targets were heterogeneous, although some clustering was observed in the dorsolateral STN and subthalamic area. In particular, in the anterior-posterior direction the intended targets differed to a great exten...
Neurosurgery, 2016
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) for the management of motor symptom... more Deep brain stimulation (DBS) of the subthalamic nucleus (STN) for the management of motor symptoms of Parkinson disease (PD) is typically performed under conscious sedation with awake evaluation during intraoperative physiologic testing. However, developments in surgical techniques now allow for subjects to be asleep during the procedure using general anesthesia. Previously reported long-term outcomes of subjects who underwent STN-DBS under general anesthesia demonstrated postoperative safety and efficacy out to 1 year. In this study, we examine outcomes between subjects undergoing the STN-DBS procedure who used general anesthesia vs those using conscious sedation with awake evaluation as part of the ongoing VANTAGE clinical trial. VANTAGE is a prospective, multicenter, nonrandomized, open-label interventional trial, sponsored by Boston Scientific Corporation. The trial assesses motor improvement in subjects with moderate-to-severe PD following bilateral STN-DBS. Assessments include motor scores such as Unified Parkinson's Disease Rating Scale (UPDRS) and quality-of-life measurements such as PDQ-39. Forty subjects were implanted bilaterally with the Vercise DBS System (Boston Scientific Corporation) at 6 European centers. Of these, 19 (47%) underwent the DBS procedure under general anesthesia. Analysis of both study groups did not indicate a statistically significant difference in motor function outcomes. However, subjects utilizing general anesthesia were found not to display motor function outcomes that were necessarily clinically inferior to those consciously sedated with awake evaluation. Sample size and variation in baseline differences in selected subjects may have contributed to these final results, because a tendency for subjects undergoing general anesthesia to report an improvement in motor function similar to or better than those consciously sedated (vs baseline) was observed. No inferiority in clinical outcomes was observed in subjects that underwent general anesthesia vs those that were consciously sedated with awake evaluation.
HAMDAN MEDICAL JOURNAL, 2016
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
ABSTRACT
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
Tiefe Hirnstimulation, 2010
ABSTRACT
Cortex; a journal devoted to the study of the nervous system and behavior, 2014
Dopaminergic denervation in Parkinson's disease (PD) leads to motor deficits but also depress... more Dopaminergic denervation in Parkinson's disease (PD) leads to motor deficits but also depression, lack of motivation and apathy. These symptoms can be reversed by dopaminergic treatment, which may even lead to an increased hedonic tone in some patients with PD. Here, we tested the effects of dopamine on emotional processing as indexed by changes in local field potential (LFP) activity of the subthalamic nucleus (STN) in 28 PD patients undergoing deep brain stimulation. LFP activity from the STN was recorded after the administration of levodopa (ON group) or after overnight withdrawal of medication (OFF group) during presentation of an emotional picture-viewing task. Neutral and emotionally arousing pleasant and unpleasant stimuli were chosen from the International Affective Picture System. We found a double dissociation of the alpha band response depending on dopamine state and stimulus valence: dopamine enhanced the processing of pleasant stimuli, while activation during unplea...
Biomedical engineering online, Jan 7, 2003
The purpose was to investigate mobile phone interference with implantable deep brain stimulators ... more The purpose was to investigate mobile phone interference with implantable deep brain stimulators by means of 10 different 900 Mega Hertz (MHz) and 10 different 1800 MHz GSM (Global System for Mobile Communications) mobile phones. All tests were performed in vitro using a phantom especially developed for testing with deep brain stimulators. The phantom was filled with liquid phantom materials simulating brain and muscle tissue. All examinations were carried out inside an anechoic chamber on two implants of the same type of deep brain stimulator: ITREL-III from Medtronic Inc., USA. Despite a maximum transmitted peak power of mobile phones of 1 Watt (W) at 1800 MHz and 2 W at 900 MHz respectively, no influence on the ITREL-III was found. Neither the shape of the pulse form changed nor did single pulses fail. Tests with increased transmitted power using CW signals and broadband dipoles have shown that inhibition of the ITREL-III occurs at frequency dependent power levels which are below...
Biomedical engineering online, Jan 12, 2002
According to manufacturers of both magnetic resonance imaging (MRI) machines, and implantable neu... more According to manufacturers of both magnetic resonance imaging (MRI) machines, and implantable neurological pulse generators (IPGs), MRI is contraindicated for patients with IPGs. A major argument for this restriction is the risk to induce heat in the leads due to the electromagnetic field, which could be dangerous for the surrounding brain parenchyma. The temperature change on the surface of the case of an ITREL-III (Medtronic Inc., Minneapolis, MN) and the lead tip during MRI was determined. An anatomical realistic and a cubic phantom, filled with phantom material mimicking human tissue, and a typical lead configuration were used to imitate a patient who carries an IPG for deep brain stimulation. The measurements were performed in a 1.5 T and a 3.0 T MRI. 2.1 degrees C temperature increases at the lead tip uncovered the lead tip as the most critical part concerning heating problems in IPGs. Temperature increases in other locations were low compared to the one at the lead tip. The m...
Acta neurochirurgica. Supplement, 1995
Randomized studies have shown that survival in patients with single brain metastases is significa... more Randomized studies have shown that survival in patients with single brain metastases is significantly higher after the combined treatment of surgical removal and whole-brain irradiation than after whole-brain radiation therapy alone. In patients with deep-seated lesions or those located in critical sites of the brain, as well as in cases in which the patient's general condition makes general anaesthesia difficult or impossible microsurgical resection usually cannot be performed or only with an increased surgical risk. Stereotactic radiosurgery, which can be done by means of convergent beam irradiation or by the implantation of highly loaded 125I seeds, provides an alternative to open procedures. In the following we report on our results using a stereotactic radiosurgical technique. A series of 20 treatments is presented, in which biopsy was performed and 125I seeds were implanted, both under stereotactic conditions in the same session. The 125I seeds were sealed in a teflon cath...
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Papers by François Alesch