References of "Krüger, Rejko 50002143"
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See detailLoss of DJ-1 impairs antioxidant response by altered glutamine and serine metabolism
Meiser, Johannes UL; Delcambre, Sylvie UL; Wegner, André UL et al

in Neurobiology of disease (2016), 89

The oncogene DJ-1 has been originally identified as a suppressor of PTEN. Further on, loss-of-function mutations have been described as a causative factor in Parkinson's disease (PD). DJ-1 has an ... [more ▼]

The oncogene DJ-1 has been originally identified as a suppressor of PTEN. Further on, loss-of-function mutations have been described as a causative factor in Parkinson's disease (PD). DJ-1 has an important function in cellular antioxidant responses, but its role in central metabolism of neurons is still elusive. We applied stable isotope assisted metabolic profiling to investigate the effect of a functional loss of DJ-1 and show that DJ-1 deficient neuronal cells exhibit decreased glutamine influx and reduced serine biosynthesis. By providing precursors for GSH synthesis, these two metabolic pathways are important contributors to cellular antioxidant response. Down-regulation of these pathways, as a result of loss of DJ-1 leads to an impaired antioxidant response. Furthermore, DJ-1 deficient mouse microglia showed a weak but constitutive pro-inflammatory activation. The combined effects of altered central metabolism and constitutive activation of glia cells raise the susceptibility of dopaminergic neurons towards degeneration in patients harboring mutated DJ-1. Our work reveals metabolic alterations leading to increased cellular instability and identifies potential new intervention points that can further be studied in the light of novel translational medicine approaches. [less ▲]

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See detailCost-Effectiveness of Neurostimulation in Parkinson's Disease With Early Motor Complications
Dams, J; Balzer-Geldsetzer, M; Siebert, U et al

in Movement Disorders : Official Journal of the Movement Disorder Society (2016), 31(8), 1183-1191

Background: Recent research efforts have focused on the effects of deep brain stimulation of the subthalamic nucleus (STN DBS) for selected patients with mild-to-moderate PD experiencing motor ... [more ▼]

Background: Recent research efforts have focused on the effects of deep brain stimulation of the subthalamic nucleus (STN DBS) for selected patients with mild-to-moderate PD experiencing motor complications. Objectives: We assessed the cost utility of subthalamic DBS compared with the best medical treatment for German patients below the age of 61 with early motor complications of PD. Methods: We applied a previously published Markov model that integrated health utilities based on EuroQoL and direct costs over patients’ lifetime adjusted to the German health care payer perspective (year of costing: 2013). Effectiveness was evaluated using the Parkinson’s Disease Questionnaire 39 summary index. We performed sensitivity analyses to assess uncertainty. Results: In the base-case analysis, the incremental cost-utility ratio for STN DBS compared to best medical treatment was 22,700 Euros per quality-adjusted life year gained. The time to, and costs for, battery exchange had a major effect on the incremental cost-utility ratios, but never exceeded a threshold of 50,000Euros per quality-adjusted life year. Conclusions: Our decision analysis supports the fact that STN DBS at earlier stages of the disease is cost-effective in patients below the age of 61 when compared with the best medical treatment in the German health care system. This finding was supported by detailed sensitivity analyses reporting robust results. Whereas the EARLYSTIM study has shown STN DBS to be superior to medical therapy with respect to quality of life for patients with early motor complications, this further analysis has shown its cost-effectiveness. [less ▲]

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See detailAlpha-synuclein gene variants may predict neurostimulation outcome.
Weiss, D.; Herrmann, S.; Wang, Lin UL et al

in Movement disorders : official journal of the Movement Disorder Society (2016)

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See detailNeuromuscular correlates of subthalamic stimulation and upper limb freezing in Parkinson's disease.
Scholten, M.; Klotz, R.; Plewnia, C. et al

in Clinical Neurophysiology (2016)

OBJECTIVE: The pathophysiology of deep brain stimulation mechanisms and resistant freezing phenomena in idiopathic Parkinson's disease (iPD) remains incompletely understood. Further studies on the ... [more ▼]

OBJECTIVE: The pathophysiology of deep brain stimulation mechanisms and resistant freezing phenomena in idiopathic Parkinson's disease (iPD) remains incompletely understood. Further studies on the neuromuscular substrates are needed. METHODS: We analyzed 16 patients with advanced iPD and bilateral subthalamic nucleus stimulation, and 13 age- and gender-matched healthy controls. Patients were tested after overnight withdrawal of medication with 'stimulation off' (StimOff) and 'stimulation on' (StimOn). Subjects performed continuous tapping of the right index finger with simultaneous recordings of biomechanical registration, EMG of finger flexors and extensors, and EEG. First, we analyzed EEG and EMG spectral measures comparing StimOff with healthy controls and StimOff with StimOn (irrespective of freezing). Second, we contrasted 'regular (unimpaired) tapping' and 'freezing' resistant to subthalamic neurostimulation as obtained in StimOn. RESULTS: iPD showed increased intermuscular coherence around 8Hz in StimOff that was reduced in StimOn. This 8Hz muscular activity was not coherent to cortical activity. 'Freezing' episodes showed increased muscle activity of finger flexors and extensors at 6-9Hz, and increased cortical activity at 7-11Hz. During transition from regular tapping to 'freezing' the cortical activity first increased over the left sensorimotor area followed by a spread to the left frontal and right parietal areas. CONCLUSIONS: We identified neuromuscular motor network features of subthalamic neurostimulation therapy and resistant upper limb freezing that point to increased low-frequency muscular and cortical activity. SIGNIFICANCE: Together, our findings demonstrate several motor network abnormalities associated with upper limb freezing that may translate into future research on freezing of gait in iPD. [less ▲]

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See detailCortical correlates of susceptibility to upper limb freezing in Parkinson's disease.
Scholten, M.; Govindan, R. B.; Braun, C. et al

in Clinical Neurophysiology (2016), 127(6), 2386-93

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See detailAdvanced stages of PD: interventional therapies and related patient-centered care
Krüger, Rejko UL; Hilker, Rudiger; Winkler, Christian et al

in Journal of neural transmission (Vienna, Austria : 1996) (2016)

During the last decades, symptomatic treatment of motor symptoms of Parkinson's disease (PD) improved continuously and is reflected by long-range independency of the patient during the disease course ... [more ▼]

During the last decades, symptomatic treatment of motor symptoms of Parkinson's disease (PD) improved continuously and is reflected by long-range independency of the patient during the disease course. However, advanced stages of PD still represent an important challenge to patients, caregivers and treating physicians. In patients with advanced PD, interventional therapy strategies are increasingly applied. These device-related treatment strategies using pump-based continuous dopaminergic stimulation (CDS) or deep brain stimulation (DBS) opened new treatment options especially if motor complications predominate. Well-designed clinical studies on these interventional therapeutic approaches provided class 1 evidence for the efficacy of DBS and CDS in advanced PD and opened new perspectives for their use in earlier disease stages also. Therefore, careful selection of patients amenable to the (semi)invasive therapy options becomes more and more important and requires an interdisciplinary setting that accounts for (i) optimal patient information and awareness, (ii) selection of best individual treatment modality, (iii) training of relatives and caregivers, (iv) management of complications, and (v) follow-up care. Here, we address these topics by summarizing current state-of-the-art in patient selection, providing specificities of treatment options and troubleshooting, and defining steps towards an optimized patient-centered care. Interventional therapies pioneer in the area of individualized treatment approaches for PD, and may be complemented in the future by biomarker-based improved stratification and by closed-loop systems for adaptive therapeutic strategies. In the present review, we summarize the proceedings of an Expert Workshop on Parkinson's disease held on November 22, 2014 in Frankfurt, Germany. [less ▲]

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See detailSubthalamic stimulation modulates cortical motor network activity and synchronization in Parkinson's disease
Weiss, D.; Klotz, R.; Govindan, R. B. et al

in Brain : a journal of neurology (2015), 138(Pt 3), 679-93

Dynamic modulations of large-scale network activity and synchronization are inherent to a broad spectrum of cognitive processes and are disturbed in neuropsychiatric conditions including Parkinson's ... [more ▼]

Dynamic modulations of large-scale network activity and synchronization are inherent to a broad spectrum of cognitive processes and are disturbed in neuropsychiatric conditions including Parkinson's disease. Here, we set out to address the motor network activity and synchronization in Parkinson's disease and its modulation with subthalamic stimulation. To this end, 20 patients with idiopathic Parkinson's disease with subthalamic nucleus stimulation were analysed on externally cued right hand finger movements with 1.5-s interstimulus interval. Simultaneous recordings were obtained from electromyography on antagonistic muscles (right flexor digitorum and extensor digitorum) together with 64-channel electroencephalography. Time-frequency event-related spectral perturbations were assessed to determine cortical and muscular activity. Next, cross-spectra in the time-frequency domain were analysed to explore the cortico-cortical synchronization. The time-frequency modulations enabled us to select a time-frequency range relevant for motor processing. On these time-frequency windows, we developed an extension of the phase synchronization index to quantify the global cortico-cortical synchronization and to obtain topographic differentiations of distinct electrode sites with respect to their contributions to the global phase synchronization index. The spectral measures were used to predict clinical and reaction time outcome using regression analysis. We found that movement-related desynchronization of cortical activity in the upper alpha and beta range was significantly facilitated with 'stimulation on' compared to 'stimulation off' on electrodes over the bilateral parietal, sensorimotor, premotor, supplementary-motor, and prefrontal areas, including the bilateral inferior prefrontal areas. These spectral modulations enabled us to predict both clinical and reaction time improvement from subthalamic stimulation. With 'stimulation on', interhemispheric cortico-cortical coherence in the beta band was significantly attenuated over the bilateral sensorimotor areas. Similarly, the global cortico-cortical phase synchronization was attenuated, and the topographic differentiation revealed stronger desynchronization over the (ipsilateral) right-hemispheric prefrontal, premotor and sensorimotor areas compared to 'stimulation off'. We further demonstrated that the cortico-cortical phase synchronization was largely dominated by genuine neuronal coupling. The clinical improvement with 'stimulation on' compared to 'stimulation off' could be predicted from this cortical decoupling with multiple regressions, and the reduction of synchronization over the right prefrontal area showed a linear univariate correlation with clinical improvement. Our study demonstrates wide-spread activity and synchronization modulations of the cortical motor network, and highlights subthalamic stimulation as a network-modulating therapy. Accordingly, subthalamic stimulation may release bilateral cortical computational resources by facilitating movement-related desynchronization. Moreover, the subthalamic nucleus is critical to balance inhibitory and facilitatory cortical players within the motor program. [less ▲]

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See detailTREM2 R47H variant and risk of essential tremor: a cross-sectional international multicenter study
Ortega-Cubero, S.; Lorenzo-Betancor, O.; Lorenzo, E. et al

in Parkinsonism & related disorders (2015), 21(3), 306-309

INTRODUCTION: Essential tremor (ET) is the most frequent movement disorder in adults. Its pathophysiology is not clearly understood, however there is growing evidence showing common etiologic factors with ... [more ▼]

INTRODUCTION: Essential tremor (ET) is the most frequent movement disorder in adults. Its pathophysiology is not clearly understood, however there is growing evidence showing common etiologic factors with other neurodegenerative disorders such as Alzheimer's and Parkinson's diseases (AD, PD). Recently, a rare p.R47H substitution (rs75932628) in the TREM2 protein (triggering receptor expressed on myeloid cells 2; OMIM: *605086) has been proposed as a risk factor for AD, PD and amyotrophic lateral sclerosis (ALS). The objective of the study was to determine whether TREM2 p.R47H allele is also a risk factor for developing ET. METHODS: This was a cross-sectional multicenter international study. An initial case-control cohort from Spain (n = 456 ET, n = 2715 controls) was genotyped. In a replication phase, a case-control series (n = 897 ET, n = 1449 controls) from different populations (Italy, Germany, North-America and Taiwan) was studied. Owed to the rarity of the variant, published results on p.R47H allele frequency from 14777 healthy controls from European, North American or Chinese descent were additionally considered. The main outcome measure was p.R47H (rs75932628) allelic frequency. RESULTS: There was a significant association between TREM2 p.R47H variant and ET in the Spanish cohort (odds ratio [OR], 5.97; 95% CI, 1.203-29.626; p = 0.042), but it was not replicated in other populations. CONCLUSIONS: These results argue in favor of population-specific differences in the allelic distribution and suggest that p.R47H (rs75932628) variant may contribute to the susceptibility of ET in Spanish population. However, taking into account the very low frequency of p.R47H, further confirmatory analyses of larger ET series are needed. [less ▲]

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See detailLow-bias phosphopeptide enrichment from scarce samples using plastic antibodies
Chen, Jing; Shinde, Sudhirkumar; Koch, Markus-Hermann et al

in Scientific reports (2015), 5

Phosphospecific enrichment techniques and mass spectrometry (MS) are essential tools for comprehending the cellular phosphoproteome. Here, we report a fast and simple approach for low sequence-bias ... [more ▼]

Phosphospecific enrichment techniques and mass spectrometry (MS) are essential tools for comprehending the cellular phosphoproteome. Here, we report a fast and simple approach for low sequence-bias phosphoserine (pS) peptide capture and enrichment that is compatible with low biological or clinical sample input. The approach exploits molecularly imprinted polymers (MIPs, "plastic antibodies") featuring tight neutral binding sites for pS or pY that are capable of cross-reacting with phosphopeptides of protein proteolytic digests. The versatility of the resulting method was demonstrated with small samples of whole-cell lysate from human embryonic kidney (HEK) 293T cells, human neuroblastoma SH-SY5Y cells, mouse brain or human cerebrospinal fluid (CSF). Following pre-fractionation of trypsinized proteins by strong cation exchange (SCX) chromatography, pS-MIP enrichment led to the identification of 924 phosphopeptides in the HEK 293T whole-cell lysate, exceeding the number identified by TiO2-based enrichment (230). Moreover, the phosphopeptides were extracted with low sequence bias and showed no evidence for the characteristic preference of TiO2 for acidic amino acids (aspartic and glutamic acid). Applying the method to human CSF led to the discovery of 47 phosphopeptides belonging to 24 proteins and revealed three previously unknown phosphorylation sites. [less ▲]

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See detailShort- and long-term outcome of chronic pallidal neurostimulation in monogenic isolated dystonia
Bruggemann, N.; Kuhn, A.; Schneider, S. A. et al

in Neurology (2015), 84(9), 895-903

OBJECTIVES: Deep brain stimulation of the internal pallidum (GPi-DBS) is an established therapeutic option in treatment-refractory dystonia, and the identification of factors predicting surgical outcome ... [more ▼]

OBJECTIVES: Deep brain stimulation of the internal pallidum (GPi-DBS) is an established therapeutic option in treatment-refractory dystonia, and the identification of factors predicting surgical outcome is needed to optimize patient selection. METHODS: In this retrospective multicenter study, GPi-DBS outcome of 8 patients with DYT6, 9 with DYT1, and 38 with isolated dystonia without known monogenic cause (non-DYT) was assessed at early (1-16 months) and late (22-92 months) follow-up using Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores. RESULTS: At early follow-up, mean reduction of dystonia severity was greater in patients with DYT1 (BFMDRS score: -60%) and non-DYT dystonia (-52%) than in patients with DYT6 dystonia (-32%; p = 0.046). Accordingly, the rate of responders was considerably lower in the latter group (57% vs >90%; p = 0.017). At late follow-up, however, GPi-DBS resulted in comparable improvement in all 3 groups (DYT6, -42%; DYT1, -44; non-DYT, -61%). Additional DBS of the same or another brain target was performed in 3 of 8 patients with DYT6 dystonia with varying results. Regardless of the genotype, patients with a shorter duration from onset of dystonia to surgery had better control of dystonia postoperatively. CONCLUSIONS: Long-term GPi-DBS is effective in patients with DYT6, DYT1, and non-DYT dystonia. However, the effect of DBS appears to be less predictable in patients with DYT6, suggesting that pre-DBS genetic testing and counseling for known dystonia gene mutations may be indicated. GPi-DBS should probably be considered earlier in the disease course. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that long-term GPi-DBS improves dystonia in patients with DYT1, DYT6, and non-DYT dystonia. [less ▲]

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See detailThe NG2 Proteoglycan Protects Oligodendrocyte Precursor Cells against Oxidative Stress via Interaction with OMI/HtrA2
Maus, F.; Sakry, D.; Biname, F. et al

in PLoS ONE (2015), 10(9), 0137311

The NG2 proteoglycan is characteristically expressed by oligodendrocyte progenitor cells (OPC) and also by aggressive brain tumours highly resistant to chemo- and radiation therapy. Oligodendrocyte ... [more ▼]

The NG2 proteoglycan is characteristically expressed by oligodendrocyte progenitor cells (OPC) and also by aggressive brain tumours highly resistant to chemo- and radiation therapy. Oligodendrocyte-lineage cells are particularly sensitive to stress resulting in cell death in white matter after hypoxic or ischemic insults of premature infants and destruction of OPC in some types of Multiple Sclerosis lesions. Here we show that the NG2 proteoglycan binds OMI/HtrA2, a mitochondrial serine protease which is released from damaged mitochondria into the cytosol in response to stress. In the cytosol, OMI/HtrA2 initiates apoptosis by proteolytic degradation of anti-apoptotic factors. OPC in which NG2 has been downregulated by siRNA, or OPC from the NG2-knockout mouse show an increased sensitivity to oxidative stress evidenced by increased cell death. The proapoptotic protease activity of OMI/HtrA2 in the cytosol can be reduced by the interaction with NG2. Human glioma expressing high levels of NG2 are less sensitive to oxidative stress than those with lower NG2 expression and reducing NG2 expression by siRNA increases cell death in response to oxidative stress. Binding of NG2 to OMI/HtrA2 may thus help protect cells against oxidative stress-induced cell death. This interaction is likely to contribute to the high chemo- and radioresistance of glioma. [less ▲]

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See detailClinically meaningful parameters of progression and long-term outcome of Parkinson disease: An international consensus statement
Puschmann, A.; Brighina, L.; Markopoulou, K. et al

in Parkinsonism & related disorders (2015), 21(7), 675-682

Parkinson disease (PD) is associated with a clinical course of variable duration, severity, and a combination of motor and non-motor features. Recent PD research has focused primarily on etiology rather ... [more ▼]

Parkinson disease (PD) is associated with a clinical course of variable duration, severity, and a combination of motor and non-motor features. Recent PD research has focused primarily on etiology rather than clinical progression and long-term outcomes. For the PD patient, caregivers, and clinicians, information on expected clinical progression and long-term outcomes is of great importance. Today, it remains largely unknown what factors influence long-term clinical progression and outcomes in PD; recent data indicate that the factors that increase the risk to develop PD differ, at least partly, from those that accelerate clinical progression and lead to worse outcomes. Prospective studies will be required to identify factors that influence progression and outcome. We suggest that data for such studies is collected during routine office visits in order to guarantee high external validity of such research. We report here the results of a consensus meeting of international movement disorder experts from the Genetic Epidemiology of Parkinson's Disease (GEO-PD) consortium, who convened to define which long-term outcomes are of interest to patients, caregivers and clinicians, and what is presently known about environmental or genetic factors influencing clinical progression or long-term outcomes in PD. We propose a panel of rating scales that collects a significant amount of phenotypic information, can be performed in the routine office visit and allows international standardization. Research into the progression and long-term outcomes of PD aims at providing individual prognostic information early, adapting treatment choices, and taking specific measures to provide care optimized to the individual patient's needs. [less ▲]

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See detailCollective physician perspectives on non-oral medication approaches for the management of clinically relevant unresolved issues in Parkinson's disease: Consensus from an international survey and discussion program
Odin, P.; Chaudhuri, K.R.; Slevin, J.T. et al

in Parkinsonism & Related Disorders (2015)

Navigate PD was an educational program established to supplement existing guidelines and provide recommendations on the management of Parkinson's disease (PD) refractory to oral/transdermal therapies. It ... [more ▼]

Navigate PD was an educational program established to supplement existing guidelines and provide recommendations on the management of Parkinson's disease (PD) refractory to oral/transdermal therapies. It involved 103 experts from 13 countries overseen by an International Steering Committee (ISC) of 13 movement disorder specialists. The ISC identified 71 clinical questions important for device-aided management of PD. Fifty-six experts responded to a web-based survey, rating 15 questions as ‘critically important;’ these were refined to 10 questions by the ISC to be addressed through available evidence and expert opinion. Draft guidance was presented at international/national meetings and revised based on feedback. Key take-home points are: - Patients requiring levodopa >5 times daily who have severe, troublesome ‘off’ periods (>1e2 h/day) despite optimal oral/transdermal levodopa or non-levodopa-based therapies should be referred for specialist assessment even if disease duration is <4 years. - Cognitive decline related to non-motor fluctuationsis an indication for device-aided therapies. If cognitive impairment is mild, use deep brain stimulation (DBS) with caution. For patients who have cognitive impairment or dementia, intrajejunal levodopa infusion is considered as both therapeutic and palliative in some countries. Falls are linked to cognitive decline and are likely to become more frequent with device-aided therapies. - Insufficient control of motor complications (or drug-resistant tremor in the case of DBS) are indications for device-aided therapies. Levodopa-carbidopa intestinal gel infusions or subcutaneous apomorphine pump may be considered for patients aged >70 years who have mild or moderate cognitive impairment, severe depression or other contraindications to DBS. [less ▲]

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See detailLong-term outcome of deep brain stimulation in fragile X-associated tremor/ataxia syndrome
Weiss, D.; Mielke, C.; Wachter, T. et al

in Parkinsonism & related disorders (2015), 21(3), 310-313

INTRODUCTION: Fragile X-associated tremor/ataxia syndrome (FXTAS) presents as complex movement disorder including tremor and cerebellar ataxia. The efficacy and safety of deep brain stimulation of the ... [more ▼]

INTRODUCTION: Fragile X-associated tremor/ataxia syndrome (FXTAS) presents as complex movement disorder including tremor and cerebellar ataxia. The efficacy and safety of deep brain stimulation of the nucleus ventralis intermedius of the thalamus in atypical tremor syndromes like FXTAS remains to be determined. METHODS: Here, we report the long-term outcome of three male genetically confirmed FXTAS patients treated with bilateral neurostimulation of the nucleus ventralis intermedius for up to four years. RESULTS: All patients demonstrated sustained improvement of both tremor and ataxia - the latter included improvement of intention tremor and axial tremor. Kinematic gait analyses further demonstrated a regularization of the gait cycle. Initial improvements of hand functional disability were not sustained and reached the preoperative level of impairment within one to two years from surgery. CONCLUSION: Our data on patients with a genetic cause of tremor show favorable outcome and may contribute to improved patient stratification for neurostimulation therapy in the future. [less ▲]

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See detailThe COMT Val/Met polymorphism modulates effects of tDCS on response inhibition
Nieratschker, V.; Kiefer, C.; Giel, K. et al

in Brain stimulation (2015), 8(2), 283-288

BACKGROUND: Transcranial direct current stimulation (tDCS) is increasingly discussed as a new option to support the cognitive rehabilitation in neuropsychiatric disorders. However, the therapeutic impact ... [more ▼]

BACKGROUND: Transcranial direct current stimulation (tDCS) is increasingly discussed as a new option to support the cognitive rehabilitation in neuropsychiatric disorders. However, the therapeutic impact of tDCS is limited by high inter-individual variability. Genetic factors most likely contribute to this variability by modulating the effects of tDCS. OBJECTIVES: We aimed to investigate the influence of the COMT Val(108/158)Met polymorphism on cathodal tDCS effects on executive functioning. METHODS: Cathodal tDCS was applied to the left dorsolateral prefrontal cortex (dlPFC) during the performance of a parametric Go/No-Go test. RESULTS: We demonstrate an impairing effect of cathodal tDCS to the dlPFC on response inhibition. This effect was only found in individuals homozygous for the Val-allele of the COMT Val(108/158)Met polymorphism. No effects of stimulation on executive functions in Met-allele carriers were detected. CONCLUSION: Our data indicate that i) cathodal, excitability reducing tDCS, interferes with inhibitory cognitive control, ii) the left dlPFC is critically involved in the neuronal network underlying the control of response inhibition, and iii) the COMT Val(108/158)Met polymorphism modulates the impact of cathodal tDCS on inhibitory control. Together with our previous finding that anodal tDCS selectively impairs set-shifting abilities in COMT Met/Met homozygous individuals, these results indicate that genetic factors modulate effects of tDCS on cognitive performance. Therefore, future tDCS research should account for genetic variability in the design and analysis of neurocognitive as well as therapeutic applications to reduce the variability of results and facilitate individualized neurostimulation approaches. [less ▲]

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See detailLarge-scale assessment of polyglutamine repeat expansions in Parkinson disease
Wang, L.; Aasly, J. O.; Annesi, G. et al

in Neurology (2015), 85(15), 1283-92

OBJECTIVES: We aim to clarify the pathogenic role of intermediate size repeat expansions of SCA2, SCA3, SCA6, and SCA17 as risk factors for idiopathic Parkinson disease (PD). METHODS: We invited ... [more ▼]

OBJECTIVES: We aim to clarify the pathogenic role of intermediate size repeat expansions of SCA2, SCA3, SCA6, and SCA17 as risk factors for idiopathic Parkinson disease (PD). METHODS: We invited researchers from the Genetic Epidemiology of Parkinson's Disease Consortium to participate in the study. There were 12,346 cases and 8,164 controls genotyped, for a total of 4 repeats within the SCA2, SCA3, SCA6, and SCA17 genes. Fixed- and random-effects models were used to estimate the summary risk estimates for the genes. We investigated between-study heterogeneity and heterogeneity between different ethnic populations. RESULTS: We did not observe any definite pathogenic repeat expansions for SCA2, SCA3, SCA6, and SCA17 genes in patients with idiopathic PD from Caucasian and Asian populations. Furthermore, overall analysis did not reveal any significant association between intermediate repeats and PD. The effect estimates (odds ratio) ranged from 0.93 to 1.01 in the overall cohort for the SCA2, SCA3, SCA6, and SCA17 loci. CONCLUSIONS: Our study did not support a major role for definite pathogenic repeat expansions in SCA2, SCA3, SCA6, and SCA17 genes for idiopathic PD. Thus, results of this large study do not support diagnostic screening of SCA2, SCA3, SCA6, and SCA17 gene repeats in the common idiopathic form of PD. Likewise, this largest multicentered study performed to date excludes the role of intermediate repeats of these genes as a risk factor for PD. [less ▲]

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See detailInitiation and dose optimization for levodopa-carbidopa intestinal gel: Insights from phase 3 clinical trials
Lew, M. F.; Slevin, J. T.; Krüger, Rejko UL et al

in Parkinsonism & related disorders (2015), 21(7), 742-748

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG) provides continuous infusion and reduces "off" time in advanced Parkinson's disease (PD) patients with motor fluctuations despite optimized ... [more ▼]

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG) provides continuous infusion and reduces "off" time in advanced Parkinson's disease (PD) patients with motor fluctuations despite optimized pharmacotherapy. METHODS: Clinical experience with 2 LCIG dosing paradigms from phase 3 studies was examined. In an open-label, 54-week study, LCIG was initiated as daytime monotherapy via nasojejunal (NJ) tube then switched to percutaneous endoscopic gastrojejunostomy (PEG-J) tube; adjunctive therapy was permitted 28 days postPEG-J. In a 12-week, double-blind, placebo-controlled, double-dummy trial, patients continued stable doses of existing anti-PD medications, but LCIG replaced daytime oral levodopa-carbidopa and was initiated directly via PEG-J. RESULTS: In the open-label study, 92% of 354 patients received monotherapy at post-PEG-J week 4; mean titration duration was 7.6 days; dosing remained stable post-titration (mean total daily dose [TDD] was 1572 mg at last visit). In the double-blind trial, 84% received polypharmacy; mean titration took 7.1 days for the LCIG arm (TDD post-titration: 1181 mg; n = 37). At post-PEG-J week 4, mean "off" time with LCIG was reduced by 3.9 h (open-label/monotherapy study) and 3.7 h (double-blind/polypharmacy trial). NJ treatment (open-label study only) required an additional procedure with related adverse events (AEs) and withdrawals. The most common AEs during PEG-J weeks 1-4 in the open-label/monotherapy and double-blind/polypharmacy trials, respectively, were complication of device insertion (35%, 57%) and abdominal pain (26%, 51%). Discontinuations due to nonprocedure/nondevice AEs were low (2.2%, 2.7%). CONCLUSION: These results support the option of initiating LCIG with or without NJ and as either monotherapy or polypharmacy. [less ▲]

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See detailMethods in Neuroepidemiology Characterization of European Longitudinal Cohort Studies in Parkinson's Disease - Report of the JPND Working Group BioLoC-PD
Lerche, S.; Liepelt-Scarfone, I.; Alves, G. et al

in Neuroepidemiology (2015), 45(4), 282-297

BACKGROUND: Enormous effort is being put into the identification and characterization of symptoms that may be used as predictive and progression markers in Parkinson's disease (PD). An impressive number ... [more ▼]

BACKGROUND: Enormous effort is being put into the identification and characterization of symptoms that may be used as predictive and progression markers in Parkinson's disease (PD). An impressive number of PD patients and individuals at risk for or in the prodromal stage of PD are currently followed in longitudinal studies; however, there does not exist an overview on the kind of markers evaluated and the assessments used. METHODS: Information on the design, sample size, evaluated markers and assessments of 21 studies of the Joint Programme - Neurodegenerative Disease Research BioLoC-PD working group were collected by questionnaire. The studies were classified into at risk/prodromal or clinical PD cohorts. The assessments were grouped into quantitative assessments, investigator-rated assessments, investigator interviews, patient-rated questionnaires and caregiver-rated questionnaires. RESULTS: Compilation of these data revealed an interesting consensus on evaluated markers, but there was an enormous variability of assessments. Furthermore, there is a remarkable similarity in the markers assessed and evaluation methods applied in the risk/prodromal and clinical PD cohorts. CONCLUSIONS: The inventory of the longitudinal cohorts that are part of the BioLoC-PD consortium reveals that there is a growing consensus on the markers that should be assessed in longitudinal cohort studies in PD. However, controversy still exists on the specific type of assessment. To allow comparison of data and common analyses it will be essential to harmonize scales and assessment outcomes. [less ▲]

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See detailComparison of beamformers for EEG source signal reconstruction
Jonmohamadi, Yaqub; Poudel; Innes, Carrie et al

in Biomedical Signal Processing and Control (2014), 14

Recently, several new beamformers have been introduced for reconstruction and localization of neural sources from EEG and MEG.Although studies have compared the accuracy of beamformers for localization of ... [more ▼]

Recently, several new beamformers have been introduced for reconstruction and localization of neural sources from EEG and MEG.Although studies have compared the accuracy of beamformers for localization of strong sources in the brain, a comparison of new and conventional beamformers for time-course reconstruction of a desired source has not been previously undertaken. In this study, 8 beamformers were examined with respectto several parameters, including variations in depth, orientation, magnitude, and frequency of the simulated source to determine their (i) effectiveness at time-course reconstruction of the sources, and (ii) stability of their performances with respect to the input changes. The spatial and directional pass-bands of the beamformers were estimated via simulated and real EEG sources to determine spatial resolution. White-noise spatial maps of the beamformers were calculated to show which beamformers have a location bias. Simulated EEG data were produced by projection via forward head modelling of simulated sources onto scalp electrodes, then superimposed on real background EEG. Real EEG was recorded from a patient with essential tremor and deep brain implanted electrodes. Gain – the ratio of SNR of the reconstructed time-course to the input SNR – was the primary measure of performance of the beamformers. Overall, minimum-variance beamformers had higher Gains and superior spatial resolution to those of the minimum-norm beamformers, although their performance was more sensitive to changes in magnitude, depth, and frequency of the simulated source. White-noise spatial maps showed that several, but not all, beamformers have an undesirable location bias. [less ▲]

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See detailFrom genome-wide association studies to next-generation sequencing: lessons from the past and planning for the future.
Sharma, Manu; Krüger, Rejko UL; Gasser, Thomas

in JAMA neurology (2014), 71(1), 5-6

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