References of "Plewnia, C"
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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 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 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 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 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 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 detailSuppression of extrapyramidal side effects of doxepin by thalamic deep brain stimulation for Tourette syndrome.
Rzesnitzek, L.; Wachter, T.; Krüger, Rejko UL et al

in Neurology (2011), 77(18), 1708-9

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