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DBS
Kinds of DBS Terms modified by DBS Selected AbstractsMRI verified STN stimulation site , gait improvement and clinical outcomeEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2010E. L. Johnsen Background:, Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is effective in alleviating Parkinson's disease (PD) symptoms (tremor, rigidity and bradykinesia) and may improve gait and postural impairment associated with the disease. However, improvement of gait is not always as predictable as the clinical outcome. This may relate to the type of gait impairment or localization of the active DBS contact. Methods:, The active contact was visualized on peri-operative magnetic resonance imaging in 22 patients with idiopathic PD, consecutively treated with bilateral STN DBS. Stimulation site was grouped as either in the dorsal/ventral STN or medial/lateral hereof and anterior/posterior STN or medial/lateral hereof. The localization was compared with relative improvement of clinical outcome (UPDRS-III). In 10 patients, quantitative gait analyses were performed, and the improvement in gait performance was compared with stimulation site in the STN. Results:, Of 44 active contacts, 77% were inside the nucleus, 23% were medial hereof. Stimulation of the dorsal half improved UPDRS-III significantly more than ventral STN DBS (P = 0.02). However, there were no differences between anterior and posterior stimulation in the dorsal STN. Step velocity and length improved significantly more with dorsal stimulation compared with ventral stimulation (P = 0.03 and P = 0.02). Balance during gait was also more improved with dorsal stimulation compared with ventral stimulation. Conclusions:, Deep brain stimulation of the dorsal STN is superior to stimulation of the ventral STN. Possible different effects of stimulation inside the nucleus underline the need for exact knowledge of the active stimulation site position to target the most effective area. [source] EFNS guidelines on neurostimulation therapy for neuropathic painEUROPEAN JOURNAL OF NEUROLOGY, Issue 9 2007G. Cruccu Pharmacological relief of neuropathic pain is often insufficient. Electrical neurostimulation is efficacious in chronic neuropathic pain and other neurological diseases. European Federation of Neurological Societies (EFNS) launched a Task Force to evaluate the evidence for these techniques and to produce relevant recommendations. We searched the literature from 1968 to 2006, looking for neurostimulation in neuropathic pain conditions, and classified the trials according to the EFNS scheme of evidence for therapeutic interventions. Spinal cord stimulation (SCS) is efficacious in failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS) type I (level B recommendation). High-frequency transcutaneous electrical nerve stimulation (TENS) may be better than placebo (level C) although worse than electro-acupuncture (level B). One kind of repetitive transcranial magnetic stimulation (rTMS) has transient efficacy in central and peripheral neuropathic pains (level B). Motor cortex stimulation (MCS) is efficacious in central post-stroke and facial pain (level C). Deep brain stimulation (DBS) should only be performed in experienced centres. Evidence for implanted peripheral stimulations is inadequate. TENS and r-TMS are non-invasive and suitable as preliminary or add-on therapies. Further controlled trials are warranted for SCS in conditions other than failed back surgery syndrome and CRPS and for MCS and DBS in general. These chronically implanted techniques provide satisfactory pain relief in many patients, including those resistant to medication or other means. [source] Effect of deep brain stimulation of the posterior hypothalamic area on the cardiovascular system in chronic cluster headache patientsEUROPEAN JOURNAL OF NEUROLOGY, Issue 9 2007P. Cortelli The objective of this study was to determine the cardiovascular effects of chronic stimulation of the posterior hypothalamic area (PHA) in cluster headache (CH) patients. Systolic and diastolic blood pressure (SBP, DBP), cardiac output, total peripheral resistance (TPR), heart rate (HR) and breathing were monitored at supine rest and during head-up tilt test (HUTT), Valsalva manoeuvre, deep breathing, cold face test and isometric handgrip in eight drug-resistant chronic CH patients who underwent monolateral electrode implantation in the PHA for therapeutic purposes. Autoregressive power spectral analysis (PSA) of HR variability (HRV) was calculated at rest and during HUTT. Each subject was studied before surgery (condition A) and after chronic deep brain stimulation (DBS) of PHA (condition B). Baseline SBP, DBP, HR and cardiovascular reflexes were normal and similar in both conditions. With respect to condition A, DBP, TPR and the LF/HF obtained from the PSA of HRV were significantly (P < 0.05) increased during HUTT in condition B. In conclusion, chronic DBS of the PHA in chronic CH patients is associated with an enhanced sympathoexcitatory drive on the cardiovascular system during HUTT. [source] A systematic review on the diagnosis and treatment of primary (idiopathic) dystonia and dystonia plus syndromes: report of an EFNS/MDS-ES Task ForceEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2006A. Albanese chairman To review the literature on primary dystonia and dystonia plus and to provide evidence-based recommendations. Primary dystonia and dystonia plus are chronic and often disabling conditions with a widespread spectrum mainly in young people. Computerized MEDLINE and EMBASE literature reviews (1966,1967 February 2005) were conducted. The Cochrane Library was searched for relevant citations. Diagnosis and classification of dystonia are highly relevant for providing appropriate management and prognostic information, and genetic counselling. Expert observation is suggested. DYT-1 gene testing in conjunction with genetic counselling is recommended for patients with primary dystonia with onset before age 30 years and in those with an affected relative with early onset. Positive genetic testing for dystonia (e.g. DYT-1) is not sufficient to make diagnosis of dystonia. Individuals with myoclonus should be tested for the epsilon-sarcoglycan gene (DYT-11). A levodopa trial is warranted in every patient with early onset dystonia without an alternative diagnosis. Brain imaging is not routinely required when there is a confident diagnosis of primary dystonia in adult patients, whereas it is necessary in the paediatric population. Botulinum toxin (BoNT) type A (or type B if there is resistance to type A) can be regarded as first line treatment for primary cranial (excluding oromandibular) or cervical dystonia and can be effective in writing dystonia. Actual evidence is lacking on direct comparison of the clinical efficacy and safety of BoNT-A vs. BoNT-B. Pallidal deep brain stimulation (DBS) is considered a good option, particularly for generalized or cervical dystonia, after medication or BoNT have failed to provide adequate improvement. Selective peripheral denervation is a safe procedure that is indicated exclusively in cervical dystonia. Intrathecal baclofen can be indicated in patients where secondary dystonia is combined with spasticity. The absolute and comparative efficacy and tolerability of drugs in dystonia, including anticholinergic and antidopaminergic drugs, is poorly documented and no evidence-based recommendations can be made to guide prescribing. [source] Review of the functional surgical treatment of dystoniaEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2001Paul Krack A review of functional surgery for dystonia is presented. Recently renewed interest in stereotaxy for dystonia has followed the resurgence of pallidotomy and the introduction of deep brain stimulation (DBS) in Parkinson's disease (PD) in the early 1990s. However, even since the 1950s, small series of patients treated with ablative surgery have been carefully studied, providing useful information, notably regarding the tolerability of surgery. In the setting of dystonia, thalamotomy was first performed with substantial benefits, but some authors outlined the great variability in outcome, and the high incidence of operative side-effects. In the ,modern' era of functional surgery for movement disorders, the globus pallidus internus (GPi) has emerged to be currently the best target for dystonia, based on small series of patients published in the last few years. Both bilateral posteroventral pallidotomy (PVP) and bilateral pallidal stimulation, performed by several teams, have benefited a variety of patients with severe dystonia, the most dramatic improvements being seen in primary dystonia with a mutation in the DYT1 gene. Whereas patients with secondary dystonia have often shown a lesser degree of improvement, some publications have nevertheless reported major benefit. There is today a strong need for carefully controlled studies comparing secondary and primary dystonia, DYT1 and non-DYT1 dystonia, ablative surgery and DBS, with additional assessment of neuropsychological changes, especially in children treated with bilateral pallidal procedures. [source] Sing the mind electric , principles of deep brain stimulationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2010Morten L. Kringelbach Abstract The remarkable efficacy of deep brain stimulation (DBS) for a range of treatment-resistant disorders is still not matched by a comparable understanding of the underlying neural mechanisms. Some progress has been made using translational research with a range of neuroscientific techniques, and here we review the most promising emerging principles. On balance, DBS appears to work by restoring normal oscillatory activity between a network of key brain regions. Further research using this causal neuromodulatory tool may provide vital insights into fundamental brain function, as well as guide targets for future treatments. In particular, DBS could have an important role in restoring the balance of the brain's default network and thus repairing the malignant brain states associated with affective disorders, which give rise to serious disabling problems such as anhedonia, the lack of pleasure. At the same time, it is important to proceed with caution and not repeat the errors from the era of psychosurgery. [source] Prior pallidotomy reduces and modifies neuronal activity in the subthalamic nucleus of Parkinson's disease patientsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2008A. Zaidel Abstract Parkinson's disease (PD) patients with prior radio-frequency lesions in the internal segment of the globus pallidus (GPi, pallidotomy), whose symptoms have deteriorated, may be candidates for further invasive treatment such as subthalamic deep brain stimulation (STN DBS). Six patients with prior pallidotomy (five unilaterally; one bilaterally) underwent bilateral STN DBS. The microelectrode recordings (MERs, used intraoperatively for STN verification), ipsilateral and contralateral to pallidotomy, and MERs from 11 matched PD patients who underwent bilateral STN DBS without prior pallidotomy were compared. For each trajectory, average, variance and mean successive difference (MSD, a measure of irregularity) of the root mean square (RMS) of the STN MER were calculated. The RMS in trajectories ipsilateral to pallidotomy showed significant reduction of the mean average and MSD of STN activity when compared with trajectories from patients without prior pallidotomy. The RMS parameters contralateral to pallidotomy tend to lie between those ipsilateral to pallidotomy and those without prior pallidotomy. The average STN power spectral density of oscillatory activity was notably lower ipsilateral to pallidotomy than contralateral, or without prior pallidotomy. The finding that pallidotomy reduces STN activity and changes firing characteristics, in conjunction with the effectiveness of STN DBS despite prior pallidotomy, calls for reappraisal and modification of the current model of the basal ganglia (BG) cortical network. It highlights the critical role of direct projections from the BG to brain-stem structures and suggests a possible GPi,STN reciprocal positive-feedback mechanism. [source] Biochemical and electrophysiological changes of substantia nigra pars reticulata driven by subthalamic stimulation in patients with Parkinson's diseaseEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2006Salvatore Galati Abstract To understand the events underlying the clinical efficacy of deep brain stimulation (DBS) of the subthalamic nucleus (STN), electrophysiological recordings and microdialysis evaluations were carried out in the substantia nigra pars reticulata (SNr), one of the two basal ganglia (BG) nuclei targeted by STN output, in patients with Parkinson's disease (PD). Clinically effective STN-DBS caused a significant increase of the SNr firing rate. The poststimulus histogram (PSTH) showed an excitation peak at 1.92,3.85 ms after the STN stimulus. The spontaneous discharge of SNr neurons was driven at the frequency of the stimulation (130 Hz), as shown in the autocorrelograms (AutoCrl). The fast Fourier transform (FFT) analysis showed a peak at 130 Hz, and a less pronounced second one at 260 Hz. Accordingly, in the distribution of the interspike intervals (ISIs), the mode was earlier, and skewness more asymmetric. Biochemically, the increased excitatory driving from the STN was reflected by a clear-cut increase in cyclic guanosine 3',5'-monophosphate (cGMP) levels in the SNr. These results indicate that the beneficial effect of DBS in PD patients is paralleled with a stimulus-synchronized activation of the STN target, SNr. Our findings suggest that, during STN-DBS, a critical change towards a high-frequency oscillatory discharge occurs. [source] The importance of dental beliefs for the outcome of dental-fear treatmentEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2003Kajsa Henning Abrahamsson This study investigated the importance of dental beliefs and the predictive value of the Dental Belief Survey (DBS) in dental-fear treatment. The sample comprised 117 adult patients seeking treatment at a dental-fear clinic. Pretreatment data were collected during a screening procedure, including two visits to the dentist. Outcome measurements were completed after treatment. The dentist rated successful/unsuccessful treatment outcome. Patients unsuccessful in treatment (n = 48) reported more initial negative dental beliefs, while patients successful in treatment (n = 69) showed a larger decrease in negative beliefs between the first and second visit to the dentist. However, these differences were small. There was a significant difference between the groups at visit two. Thus, patients unsuccessful in treatment reported more negative beliefs about how dentists communicate. Regression analyses showed that improved dental beliefs during the first two visits to the dentist predicted dental-fear reduction, while longer avoidance time, female gender, low engagement in treatment, and depressed mood increased the risk of unsuccessful treatment outcome. Our results suggest that the DBS provides valuable information, and that patients' subjective perceptions about how dentists communicate are important for treatment outcome. However, initial dental beliefs were not found to predict clinical treatment outcome. [source] Factors related to missed and cancelled dental appointments among adolescents in NorwayEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2000Erik Skaret The aim of this study was to explore possible explanatory factors related to high frequency of missed/cancelled dental appointments during the age group 12,18 yr. A total of 754 20 yr olds completed a questionnaire including variables measuring demographics, occupation (school/job), attendance pattern, attitudes to dentists, opinion about importance of dental treatment, and the psychometric scales Dental Fear Scale (DFS), Dental Beliefs Survey (DBS) and Geer Fear Scale (GFS). Based on written consents, the following data were recorded from their dental records: the total number of scheduled appointments, the number of missed and cancelled appointments and the individual caries experience of those in the age group 12,18 yr. A total of 124 subjects who had missed/cancelled 20% or more of their dental appointments during this age were defined as a target group. A stepwise regression model indicated that the likelihood of being included in the target group increased by a factor of 6.0 if the subject had forgotten dental appointments during the last 5 yr, by a factor of 3.5 for working or without specified occupation (as opposed to attending school), by a factor of 2.7 for negative beliefs of dentists, and by a factor of 2.1 for high caries experience. [source] Energy-Modulated Heterostructures Made with Conjugated Polymers for Directional Energy Transfer and Carrier Confinement,ADVANCED FUNCTIONAL MATERIALS, Issue 15 2007R. Favarim Abstract In this paper we demonstrate that multilayer structures with modulated bandgaps can be used for efficient energy transfer and carrier confinement inside a nanostructured film of a light-emitting polymer. The films were produced with the layer-by-layer technique (LbL) with a poly(p -phenylene vinylene) (PPV) precursor and a long chain dodecylbenzenesulfonate ion (DBS). DBS is incorporated selectively into the precursor chain, and with a rapid, low temperature conversion process (100,°C) superstructures with variable HOMO,LUMO gap could be formed along the deposition direction by changing the DBS concentration. Structures with different stair-type energy modulations were produced, which are thermally stable and reproducible, as demonstrated by UV-VIS. absorption measurements. Energy differences of up to 0.5,eV between the lowest and highest conjugated layers inside the stair structure could be achieved, which was sufficient to guide the excitation over long distances to the lower bandgap layer. [source] Effect on Sleep of Posterior Hypothalamus Stimulation in Cluster HeadacheHEADACHE, Issue 7 2007Roberto Vetrugno MD Objective.,To evaluate the structure and quality of sleep and the circadian rhythm of body core temperature (BcT°) in patients with drug-resistant chronic cluster headache (CH) before and during deep brain stimulation (DBS) of the posterior hypothalamus. Background.,Chronic CH is a severe primary headache and frequently associated with disturbances in sleep. Posterior hypothalamus DBS is performed as an effective treatment of drug-resistant chronic CH. The effects of posterior hypothalamus DBS on sleep and the circadian rhythm of BcT° are unknown. Methods.,Three male patients with chronic drug-resistant CH underwent 48-hour consecutive polysomnography (PSG) by means of the VITAPORT® system with determination of BcT° by means of a rectal probe. Recordings were done before electrode implantation in the posterior hypothalamus and after optimized DBS of posterior hypothalamus. Results.,Before electrode implantation PSG showed nocturnal CH attacks, reduced sleep efficiency, fragmented sleep and increased periodic limb movements in sleep (PLMS). During DBS nocturnal CH attacks were abolished and sleep efficiency and PLMS improved. BcT° circadian rhythm was normal both before and during DBS. Conclusions.,Our data show that DBS of posterior hypothalamus in drug-resistant chronic CH is effective in curtailing nocturnal CH attacks, and is associated with improved sleep structure and quality. Chronic CH displays a normal circadian rhythm of BcT°, unchanged during hypothalamic DBS. [source] Molecular neonatal screening for homocystinuria in the Qatari population,HUMAN MUTATION, Issue 6 2009Johannes Zschocke Abstract We report the results of molecular neonatal screening for homocystinuria (cystathionine beta-synthase deficiency) in neonates of Qatari origin, developed in conjunction with a novel biochemical screening approach. DNA was extracted from dried blood spots (DBS); the prevalent Qatari CBS gene mutation p.R336C (c.1006C>T) and a second mutation were tested with specific TaqMan assays. Over a period of 2 years we screened 12,603 neonates and identified six affected neonates homozygous for p.R336C. There were 225 heterozygous carriers for p.R336C. One additional child with homocystinuria detected through biochemical screening was homozygous for a mutation not previously identified in Qatar. Homocystinuria in the Qatari population has an incidence of 1:1,800, the highest in the world and even higher than previously estimated. Allele frequency of the mutation p.R336C is approximately 1%, displaying a significant deviation from Hardy Weinberg equilibrium. In conclusion, first-line molecular neonatal screening is technically feasible and may be developed as an option for presymptomatic identification of genetic disorders caused by specific mutations or a limited number of prevalent mutations. However, sensitivity for the diagnosis of disorders caused by various mutations is limited even in a homogeneous population such as Qatar. Hum Mutat 30:1,2, 2009. © 2009 Wiley-Liss, Inc. [source] Cognition following bilateral deep brain stimulation surgery of the subthalamic nucleus for Parkinson's diseaseINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 5 2009Casey H. Halpern Abstract Objective Parkinson's disease (PD) is a neurodegenerative disorder characterized by significant motor dysfunction and various non-motor disturbances, including cognitive alterations. Deep brain stimulation (DBS) is an increasingly utilized therapeutic option for patients with PD that yields remarkable success in alleviating disabling motor symptoms. DBS has additionally been associated with changes in cognition, yet the evidence is not consistent across studies. The following review sought to provide a clearer understanding of the various cognitive sequelae of bilateral subthalamic nucleus (STN) DBS while taking into account corresponding neuroanatomy and potential confounding variables. Design A literature search was performed using the following inclusion criteria: (1) at least five subjects followed for a mean of at least 3 months after surgery; (2) pre- and postoperative cognitive data using at least one standardized measure; (3) adequate report of study results using means and standard deviations. Results Two recent meta-analyses found mild post-operative impairments in verbal learning and executive function in patients who underwent DBS surgery. However, studies have revealed improved working memory and psychomotor speed in the ,on' vs ,off' stimulation state. A deficit in language may be a consequence of the surgical procedure. Conclusions While cognitive decline has been observed in some domains, our review of the data suggests that STN DBS is a worthwhile and safe method to treat PD. Copyright © 2008 John Wiley & Sons, Ltd. [source] Integrating the scene length characteristics of MPEG video bitstreams into a direct broadcast satellite network with return channel systemINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2004Fatih Alagöz Abstract In order to optimize the network resources, we should incorporate all the available information into the network design. However, incorporating irrelevant information may increase the design complexity and/or decrease the performance of the network. In this paper, we investigate the relevance of integrating the scene length characteristics of moving pictures expert group (MPEG) coded video bitstreams into a direct broadcast satellite (DBS) network with return channel system (DVB-RCS). Due to the complexity of the studied system, unless disputable simplifications are made, it is hard to achieve a mathematical foundation for this integration. Our analysis relies on extensive set of simulations. Firstly, we achieve the scene length distributions for MPEG bitstreams based on the proposed scene change models and their subjective observations of the actual video. We show that these models may be used to estimate the scene length of MPEG bitstreams. We then integrate this estimation into a DBS network simulator. Finally, we show that the scene length characteristics may be used to improve the DBS network performance under certain conditions. Copyright © 2004 John Wiley & Sons, Ltd. [source] Hierarchy crystallization structure of a polypropylene random copolymer injection-molded bar induced by a nucleating agentJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Yong Wang Abstract In this work, the effect of a nucleating agent on the crystallization structure of an injection-molded bar of a polypropylene random copolymer (PPR) with sorbitol derivatives [1,2,3,4-dibenzylidene sorbitol (DBS)] has been studied. The results show that pure PPR forms a simple skin,core crystallization structure. However, PPR/DBS forms an interesting and complicated hierarchy crystallization structure: there is a transition layer between the skin layer and the core zone. In this transition layer, the crystallization structure consists of some perfect spherulites and many tiny crystallites. Further research suggests that the formation of the hierarchy crystallization structure depends on not only the content of the nucleating agent in the PPR matrix but also the mold temperature during the injection-molding processing. The crystallization behavior of PPR/DBS during the cooling process has been characterized with polarization optical microscopy and differential scanning calorimetry. The results suggest that there are different mechanisms in the crystallization process of PPR/DBS. The formation of a three-dimensional DBS network under a certain condition might be the main reason for the complicated hierarchy crystallization structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] False-positive analysis of functional MRI during simulated deep brain stimulation: A phantom studyJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2008Ho-Ling Liu PhD Abstract Purpose To investigate the false-positive activations/deactivations in functional MRI (fMRI) of deep brain stimulation (DBS) using a phantom. Materials and Methods fMRI experiments were performed on a 1.5T scanner using a single-shot gradient-echo echo-planar imaging (GE-EPI) sequence (TR/TE/FA = 6000 msec/60 msec/90°) on an agar-gel phantom inserted with DBS electrodes. During the experimental blocks, two-second stimuli were delivered during the interscan waiting time (ISWT), which was adjusted by changing the number of slices acquired within the TR (3500 msec with 30 slices and 5160 msec with 10 slices). Data were analyzed using SPM2 software, and the false-positive voxels were detected with five different P-value thresholds. Results The number of false-positive voxels in experimental conditions had no significant differences from those in control conditions with either long or short ISWT, which increased with the P-value threshold from zero at P < 0.0001 to approximately 40 at P < 0.05. The pattern of increasing number of false-positive reactions along with P-value was similar between all conditions. Conclusion False-positive findings from fMRI with similar experimental design can be well controlled with a statistical threshold of P < 0.001 or tighter. The short ISWT of 3500 msec did not increase false-positive reactions compared to the long ISWT of 5160 msec. J. Magn. Reson. Imaging 2008;27:1439,1442. © 2008 Wiley-Liss, Inc. [source] Neurostimulation systems for deep brain stimulation: In vitro evaluation of magnetic resonance imaging,related heating at 1.5 teslaJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2002Ali R. Rezai MD Abstract Purpose To assess magnetic resonance imaging (MRI)-related heating for a neurostimulation system (Activa® Tremor Control System, Medtronic, Minneapolis, MN) used for chronic deep brain stimulation (DBS). Materials and Methods Different configurations were evaluated for bilateral neurostimulators (Soletra® Model 7426), extensions, and leads to assess worst-case and clinically relevant positioning scenarios. In vitro testing was performed using a 1.5-T/64-MHz MR system and a gel-filled phantom designed to approximate the head and upper torso of a human subject. MRI was conducted using the transmit/receive body and transmit/receive head radio frequency (RF) coils. Various levels of RF energy were applied with the transmit/receive body (whole-body averaged specific absorption rate (SAR); range, 0.98,3.90 W/kg) and transmit/receive head (whole-body averaged SAR; range, 0.07,0.24 W/kg) coils. A fluoroptic thermometry system was used to record temperatures at multiple locations before (1 minute) and during (15 minutes) MRI. Results Using the body RF coil, the highest temperature changes ranged from 2.5°,25.3° C. Using the head RF coil, the highest temperature changes ranged from 2.3°,7.1° C.Thus, these findings indicated that substantial heating occurs under certain conditions, while others produce relatively minor, physiologically inconsequential temperature increases. Conclusion The temperature increases were dependent on the type of RF coil, level of SAR used, and how the lead wires were positioned. Notably, the use of clinically relevant positioning techniques for the neurostimulation system and low SARs commonly used for imaging the brain generated little heating. Based on this information, MR safety guidelines are provided. These observations are restricted to the tested neurostimulation system. J. Magn. Reson. Imaging 2002;15:241,250. © 2002 Wiley-Liss, Inc. [source] Human immunodeficiency virus serotyping on dried serum spots as a screening tool for the surveillance of the AIDS epidemicJOURNAL OF MEDICAL VIROLOGY, Issue S1 2006Francis Barin Abstract Many studies have demonstrated the utility of the dried blood spot (DBS) or dried plasma/serum spot (DSS) method for serological and molecular diagnosis of HIV infection. Here, we report on the description of a serotyping assay performed on DSS, and its application to a national surveillance program of HIV variants. We combined serotyping assays that we developed previously to discriminate between HIV-1 and HIV-2, between HIV-1 group O and HIV-1 group M, and between B and non-B subtypes of HIV-1 group M. The assays are based on antibody binding to either the immunodominant epitope of gp41 or the V3 domain of gp120 of these various types, groups and subtypes. Therefore, a unique enzyme-linked immunosorbent assay (ELISA) format applied to serum eluted from DSS allowed the simultaneous discrimination between infections caused by HIV-1 B, HIV-1 non-B, HIV-1 group O, and HIV-2. Together, this serotyping assay and an immunoassay for recent infection were used for a virological surveillance linked to the anonymous mandatory notification of HIV infection in France. The preliminary results of this virological surveillance allowed us to obtain estimates of the prevalence of the rare variants HIV-2 and HIV-1 group O. It also allowed identification of the two first cases of M/O dual infections reported outside the endemic group O region of the western part of equatorial Africa, and showed that non-B subtypes circulate widely in France, almost 50% of new HIV diagnoses in 2003 being due to these variants. J. Med. Virol. 78:S13,S18, 2006. © 2006 Wiley-Liss, Inc. [source] Effects of Drink-Stress Sequence and Gender on Alcohol Stress Response Dampening in High and Low Anxiety Sensitive DrinkersALCOHOLISM, Issue 3 2007Martin Zack Background: This study tested the appraisal disruption hypothesis of alcohol stress response dampening (SRD) in male and female high or low anxiety sensitive (AS) undergraduates. The hypothesis predicts that alcohol SRD will be greater when drinking occurs before versus after stress exposure. High AS males' predominant social-evaluative concerns further implied that alcohol SRD to a social stressor (i.e., a speech) would be relatively stronger in high AS males than in high AS females. Methods: Male and female (n=90/gender) high and low AS participants (,70th; ,30th percentile on Anxiety Sensitivity Index-Revised) were matched on drinking habits and randomly assigned to 1 of 9 experimental cells. Drink type,alcohol (0.7 g/kg males; 0.63 g/kg females), placebo, soda,was fully crossed with stress condition,drink before stress (DBS), drink after stress (DAS), and no stress control (NSC). Stress was induced by telling participants they would be required to make a self-revealing speech. Stress response dampening was assessed for state anxiety on the Spielberger scale and Stroop interference to threat-related words. Subjective desire for alcohol was also assessed. Results: Relative to placebo, alcohol (peak blood alcohol concentration, 0.064%) reliably reduced state anxiety in high AS but not in low AS participants. Alcohol decreased STAI scores and Stroop interference to social threat words significantly more in the DBS than the DAS condition in high AS males; high AS females displayed the exact opposite pattern of effects. In contrast to other participants, high AS males also reported relatively strong desire scores under alcohol. Conclusions: Overall, the results do not support the appraisal disruption hypothesis as a general mechanism of alcohol SRD in undergraduate drinkers. The findings for high AS males do support the hypothesis, while the opposing profile for high AS females implies that the nature of the stressor (i.e., social challenge) may contribute to gender differences in alcohol SRD in high AS individuals. [source] Long-term results of a multicenter study on subthalamic and pallidal stimulation in Parkinson's disease,MOVEMENT DISORDERS, Issue 5 2010Elena Moro MD Abstract We report the 5 to 6 year follow-up of a multicenter study of bilateral subthalamic nucleus (STN) and globus pallidus internus (GPi) deep brain stimulation (DBS) in advanced Parkinson's disease (PD) patients. Thirty-five STN patients and 16 GPi patients were assessed at 5 to 6 years after DBS surgery. Primary outcome measure was the stimulation effect on the motor Unified Parkinson's Disease Rating Scale (UPDRS) assessed with a prospective cross-over double-blind assessment without medications (stimulation was randomly switched on or off). Secondary outcomes were motor UPDRS changes with unblinded assessments in off- and on-medication states with and without stimulation, activities of daily living (ADL), anti-PD medications, and dyskinesias. In double-blind assessment, both STN and GPi DBS were significantly effective in improving the motor UPDRS scores (STN, P < 0.0001, 45.4%; GPi, P = 0.008, 20.0%) compared with off-stimulation, regardless of the sequence of stimulation. In open assessment, both STN- and GPi-DBS significantly improved the off-medication motor UPDRS when compared with before surgery (STN, P < 0.001, 50.5%; GPi, P = 0.002, 35.6%). Dyskinesias and ADL were significantly improved in both groups. Anti-PD medications were significantly reduced only in the STN group. Adverse events were more frequent in the STN group. These results confirm the long-term efficacy of STN and GPi DBS in advanced PD. Although the surgical targets were not randomized, there was a trend to a better outcome of motor signs in the STN-DBS patients and fewer adverse events in the GPi-DBS group. © 2010 Movement Disorder Society [source] Two-year follow-up on the effect of unilateral subthalamic deep brain stimulation in highly asymmetric Parkinson's disease,MOVEMENT DISORDERS, Issue 3 2009Han-Joon Kim MD Abstract Although bilateral subthalamic deep brain stimulation (STN DBS) provides greater relief from the symptoms of Parkinson's disease (PD) than unilateral STN DBS, it has been suggested that unilateral STN DBS may be a reasonable treatment option in selected patients, especially those with highly asymmetric PD. In previous studies on the effect of unilateral STN DBS, the asymmetry of PD symptoms was not prominent and the mean follow-up durations were only 3 to 12 months. In this study, we report our findings in a series of 8 patients with highly asymmetric PD who were treated with unilateral STN DBS and were followed for 24 months. Serial changes in Unified Parkinson's Disease Rating Scale (UPDRS) motor score and subscores in the ipsilateral, contralateral, and axial body parts were analyzed. Unilateral STN DBS improved the UPDRS motor score and the contralateral subscore in the on -medication state for 5 nonfluctuating patients and in the off -medication state for 3 fluctuating patients. However, the ipsilateral subscore progressively worsened and reversed asymmetry became difficult to manage, which led to compromised medication and stimulator adjustment. At 24 months, all the patients were considering the second-side surgery. Our results suggest that bilateral STN DBS should be considered even in highly asymmetric PD. © 2008 Movement Disorder Society [source] Latest view on the mechanism of action of deep brain stimulation,MOVEMENT DISORDERS, Issue 15 2008Constance Hammond PhD Abstract How does deep brain stimulation (DBS) applied at high frequency (100 Hz and above, HFS) in diverse points of cortico-basal ganglia thalamo-cortical loops alleviate symptoms of neurological disorders such as Parkinson's disease, dystonia, and obsessive compulsive disorders? Do the effects of HFS stem solely or even largely from local effects on the stimulated brain structure or are they also mediated by actions of HFS on distal structures? Indeed, HFS as an extracellular stimulation is expected to activate subsets of both afferent and efferent axons, leading to antidromic spikes that collide with ongoing spontaneous ones and orthodromic spikes that evoke synaptic responses in target neurons. The present review suggests that HFS interfere with spontaneous pathological patterns by introducing a regular activity in several nodal points of the network. Therefore, the best site of implantation of the HFS electrode may be in a region where the HFS-driven activity spreads to most of the identified, dysrhythmic, neuronal populations without causing additional side effects. This should help tackling the most difficult issue namely, how does the regular HFS-driven activity that dampens the spontaneous pathological one, restore neuronal processing along cortico-basal ganglia-thalamo-cortical loops? © 2008 Movement Disorder Society [source] Successful thalamic deep brain stimulation for orthostatic tremorMOVEMENT DISORDERS, Issue 13 2008Jorge Guridi MD Abstract We report a patient with severe orthostatic tremor (OT) unresponsive to pharmacological treatments that was successfully controlled with thalamic (Vim, ventralis intermedius nucleus) deep brain stimulation (DBS) over a 4-year period. Cortical activity associated with the OT revealed by EEG back-averaging and fluoro-deoxi-glucose PET were also suppressed in parallel with tremor arrest. This case suggests that Vim-DBS may be a useful therapeutic approach for patients highly disabled by OT. © 2008 Movement Disorder Society [source] Bilateral deep brain stimulation of the globus pallidus internus in tardive dystonia,MOVEMENT DISORDERS, Issue 13 2008Wataru Sako MD Abstract Tardive dystonia is a disabling movement disorder as a consequence of exposure to neuroleptic drugs. We followed 6 patients with medically refractory tardive dystonia treated by bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) for 21 ± 18 months. At last follow-up, the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) motor score improved by 86% ± 14%, and the BFMDRS disability score improved by 80% ± 12%. Bilateral GPi-DBS is a beneficial therapeutic option for the long-term relief of tardive dystonia. © 2008 Movement Disorder Society [source] What relation is there between deep brain stimulation and coping strategies in Parkinson's disease?,MOVEMENT DISORDERS, Issue 12 2008Sébastien Montel PhD Abstract We investigated the effect of the deep brain stimulation (DBS) on coping strategies while taking depression into account. Patients with Parkinson's disease (PD) were divided into three groups matched for sex, age, and disease severity: one, just before DBS, another at 12 months post DBS, and a group of patients not being considered for DBS. Each patient was asked to complete two self-reports about their coping styles: The ways of coping check list and the coping with health, injuries, and problems scale. The Montgomery and Asberg depression rating scale was assessed by a psychologist. After control for depression, significant differences were noticed concerning two coping strategies: instrumental (P < 0.01) and emotional (P < 0.05) ones, with higher instrumental coping strategies (seeking more information) for patients prior DBS and higher emotional strategies (avoidance, emotional preoccupation) for patients not being considered for surgery. These results confirmed our clinical impression that coping strategies differ as a function of the surgical status of PD patients. © 2008 Movement Disorder Society. [source] Deep brain stimulation hardware complications: The role of electrode impedance and current measurementsMOVEMENT DISORDERS, Issue 5 2008MPAS, Sierra Farris PAC Abstract Deep brain stimulation (DBS) is an effective therapy for advanced Parkinson's disease patients. Successful DBS outcomes depend on appropriate patient selection, surgical placement of the lead, intact hardware systems, optimal programming, and medical management. Despite its importance, there is little guidance in reference to hardware monitoring, hardware troubleshooting, and patient management. Technical manuals produced by the hardware manufacturer (Medtronic, Minneapolis, MN) are not presented in an applied clinical format, making impedance and current measurements difficult to interpret when the results are not straightforward. We present four patients with evolving DBS hardware complications that occurred during long-term follow-up, that shaped our clinical protocol for long-term care management and hardware troubleshooting. © 2007 Movement Disorder Society [source] Paradoxes of functional neurosurgery: Clues from basal ganglia recordingsMOVEMENT DISORDERS, Issue 1 2008Peter Brown MD Abstract Deep brain stimulation (DBS) can be remarkably effective in treating movement disorders such as Parkinson's disease, dystonia, and essential tremor. Yet these effects remain essentially unexplained, even paradoxical. Equally challenging is the fact that DBS of motor targets in the basal ganglia appears to reverse abnormalities of movement without any obvious deleterious effects on remaining aspects of movement. Here, we explore the extent to which the noisy signal hypothesis might help solve some of these apparent paradoxes. Essentially the hypothesis, first tentatively advanced by Marsden and Obeso (1994), suggests that disease leads to a pattern of basal ganglia activity that disrupts local and distant function and that surgery acts to suppress or override this noisy signal. Critical to the success this theory is that different disease phenotypes are associated with different patterns of noisy signal, and we survey the evidence to support this contention, with specific emphasis on different types of pathological synchronization. However, just as DBS may suppress or override noisy signals in the basal ganglia, it must equally antagonize any remaining physiological functioning in these key motor structures. We argue that the latter effect of DBS becomes manifest when baseline motor performance is relatively preserved, i.e., when pathological activity is limited. Under these circumstances, the deleterious effects of DBS are no longer obscured by its therapeutic actions in suppressing noisy signals. Whether true, oversimplified or simply incorrect, the noisy signal hypothesis has served to focus attention on the detailed character of basal ganglia discharge and its variation with disease and therapy. © 2007 Movement Disorder Society [source] Deep brain stimulation for the treatment of atypical parkinsonismMOVEMENT DISORDERS, Issue 15 2007Ludy C. Shih MD Abstract Deep brain stimulation (DBS) has gained widespread acceptance for improving motor function and disability in Parkinson's disease (PD). Patients with features suggestive of atypical parkinsonism (AP) usually have a poorer and less sustained response to levodopa and a poorer prognosis overall when compared with patients with PD. However, experience in the use of DBS with this group of patients is limited and evidence is lacking with regards to its efficacy and adverse effects. We review in detail the experience of DBS surgery in patients with several forms of AP including multiple system atrophy. On the basis of the limited available data reviewed here, DBS for patients with AP is not recommended. © 2007 Movement Disorder Society [source] Gender differences in patients with Parkinson's disease treated with subthalamic deep brain stimulationMOVEMENT DISORDERS, Issue 8 2007Ettore Accolla MD Abstract We investigated gender-differences in clinical phenomenology and response to deep brain stimulation (DBS) of the subthalamic nucleus (STN) in a group of patients with advanced Parkinson's disease (PD). Thirty-eight consecutive patients with PD (22 men and 16 women), bilaterally implanted for DBS of the STN, were evaluated 1 month before and 11 to 14 months after surgery. Gender differences in severity of the disease (HY and UPDRS), ability in the activities of daily living (ADL, UPDRS II), tremor and rigidity (UPDRS III), bradykinesia (UPDRS III and hand tapping test), levodopa-induced dyskinesias (LIDs, UPDRS IV), and levodopa equivalent daily dosage (LEDD) were analyzed before and after intervention. We found a predominantly male population, with no gender-related differences in age at onset, disease progression rate, or severity of disease. Nevertheless, women had more severe LIDs than men, only before the intervention. Bradykinesia was significantly less responsive to any kind of treatment (pharmacologic and neurosurgical) in women than in men. Finally, although STN-DBS induced similar total benefits in both genders, postoperative assessment suggested that the ADL improved more in women than in men. Women and men with advanced PD appear to differ in some clinical features and in response to dopaminergic and STN-DBS treatment. © 2007 Movement Disorder Society [source] | |||||||||||||||||||||||||||||||||||||