References of "Wachter, Tobias"
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See detailThe subthalamic nucleus modulates the early phase of probabilistic classification learning.
Weiss, Daniel; Lam, Judith M.; Breit, Sorin et al

in Experimental brain research (2014), 232(7), 2255-62

Previous models proposed that the subthalamic nucleus (STN) is critical in the early phase of skill acquisition. We hypothesized that subthalamic deep brain stimulation modulates the learning curve in ... [more ▼]

Previous models proposed that the subthalamic nucleus (STN) is critical in the early phase of skill acquisition. We hypothesized that subthalamic deep brain stimulation modulates the learning curve in early classification learning. Thirteen idiopathic Parkinson's disease patients (iPD) with subthalamic deep brain stimulation (STN-DBS), 9 medically treated iPD, and 21 age-matched healthy controls were tested with a probabilistic classification task. STN-DBS patients were tested with stimulation OFF and ON, and medically treated patients with medication OFF and ON, respectively. Performance and reaction time were analyzed on the first 100 consecutive trials as early learning phase. Moreover, data were separated for low and high-probability patterns, and more differentiated strategy analyses were used. The major finding was a significant modulation of the learning curve in DBS patients with stimulation ON: although overall learning was similar to healthy controls, only the stimulation ON group showed a transient significant performance dip from trials '41-60' that rapidly recovered. Further analysis indicated that this might be paralleled by a modulation of the learning strategy, particularly on the high-probability patterns. The reaction time was unchanged during the dip. Our study supports that the STN serves as a relay in early classification learning and directs attention toward unacquainted content. The STN might play a role in balancing the short-term success against strategy optimization for improved long-term outcome. [less ▲]

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See detailNigral stimulation for resistant axial motor impairment in Parkinson's disease? A randomized controlled trial.
Weiss, Daniel; Walach, Margarete; Meisner, Christoph et al

in Brain : a journal of neurology (2013), 136(Pt 7), 2098-108

Gait and balance disturbances typically emerge in advanced Parkinson's disease with generally limited response to dopaminergic medication and subthalamic nucleus deep brain stimulation. Therefore ... [more ▼]

Gait and balance disturbances typically emerge in advanced Parkinson's disease with generally limited response to dopaminergic medication and subthalamic nucleus deep brain stimulation. Therefore, advanced programming with interleaved pulses was put forward to introduce concomittant nigral stimulation on caudal contacts of a subthalamic lead. Here, we hypothesized that the combined stimulation of subthalamic nucleus and substantia nigra pars reticulata improves axial symptoms compared with standard subthalamic nucleus stimulation. Twelve patients were enrolled in this 2 x 2 cross-over double-blind randomized controlled clinical trial and both the safety and efficacy of combined subthalamic nucleus and substantia nigra pars reticulata stimulation were evaluated compared with standard subthalamic nucleus stimulation. The primary outcome measure was the change of a broad-scaled cumulative axial Unified Parkinson's Disease Rating Scale score (Scale II items 13-15, Scale III items 27-31) at '3-week follow-up'. Secondary outcome measures specifically addressed freezing of gait, balance, quality of life, non-motor symptoms and neuropsychiatric symptoms. For the primary outcome measure no statistically significant improvement was observed for combined subthalamic nucleus and substantia nigra pars reticulata stimulation at the '3-week follow-up'. The secondary endpoints, however, revealed that the combined stimulation of subthalamic nucleus and substantia nigra pars reticulata might specifically improve freezing of gait, whereas balance impairment remained unchanged. The combined stimulation of subthalamic nucleus and substantia nigra pars reticulata was safe, and of note, no clinically relevant neuropsychiatric adverse effect was observed. Patients treated with subthalamic nucleus and substantia nigra pars reticulata stimulation revealed no 'global' effect on axial motor domains. However, this study opens the perspective that concomittant stimulation of the substantia nigra pars reticulata possibly improves otherwise resistant freezing of gait and, therefore, highly warrants a subsequent phase III randomized controlled trial. [less ▲]

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See detailLong-term follow-up of subthalamic nucleus stimulation in glucocerebrosidase-associated Parkinson's disease.
Weiss, Daniel; Brockmann, Kathrin; Srulijes, Karin et al

in Journal of neurology (2012), 259(9), 1970-2

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See detailDeep-brain-stimulation does not impair deglutition in Parkinson's disease.
Lengerer, Sabrina; Kipping, Judy; Rommel, Natalie et al

in Parkinsonism & related disorders (2012), 18(7), 847-53

OBJECTIVE: A large proportion of patients with Parkinson's disease develop dysphagia during the course of the disease. Dysphagia in Parkinson's disease affects different phases of deglutition, has a ... [more ▼]

OBJECTIVE: A large proportion of patients with Parkinson's disease develop dysphagia during the course of the disease. Dysphagia in Parkinson's disease affects different phases of deglutition, has a strong impact on quality of life and may cause severe complications, i.e., aspirational pneumonia. So far, little is known on how deep-brain-stimulation of the subthalamic nucleus influences deglutition in PD. METHODS: Videofluoroscopic swallowing studies on 18 patients with Parkinson's disease, which had been performed preoperatively, and postoperatively with deep-brain-stimulation-on and deep-brain-stimulation-off, were analyzed retrospectively. The patients were examined in each condition with three consistencies (viscous, fluid and solid). The 'New Zealand index for multidisciplinary evaluation of swallowing (NZIMES) Subscale One' for qualitative and 'Logemann-MBS-Parameters' for quantitative evaluation were assessed. RESULTS: Preoperatively, none of the patients presented with clinically relevant signs of dysphagia. While postoperatively, the mean daily levodopa equivalent dosage was reduced by 50% and deep-brain-stimulation led to a 50% improvement in motor symptoms measured by the UPDRS III, no clinically relevant influence of deep-brain-stimulation-on swallowing was observed using qualitative parameters (NZIMES). However quantitative parameters (Logemann scale) found significant changes of pharyngeal parameters with deep-brain-stimulation-on as compared to preoperative condition and deep-brain-stimulation-off mostly with fluid consistency. CONCLUSION: In Parkinson patients without dysphagia deep-brain-stimulation of the subthalamic nucleus modulates the pharyngeal deglutition phase but has no clinically relevant influence on deglutition. Further studies are needed to test if deep-brain-stimulation is a therapeutic option for patients with swallowing disorders. [less ▲]

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See detailCombined STN/SNr-DBS for the treatment of refractory gait disturbances in Parkinson's disease: study protocol for a randomized controlled trial.
Weiss, Daniel; Wachter, Tobias; Meisner, Christoph et al

in Trials (2011), 12

BACKGROUND: Severe gait disturbances in idiopathic Parkinson's disease (PD) are observed in up to 80% of all patients in advanced disease stages with important impact on quality of life. There is an unmet ... [more ▼]

BACKGROUND: Severe gait disturbances in idiopathic Parkinson's disease (PD) are observed in up to 80% of all patients in advanced disease stages with important impact on quality of life. There is an unmet need for further symptomatic therapeutic strategies, particularly as gait disturbances generally respond unfavourably to dopaminergic medication and conventional deep brain stimulation of the subthalamic nucleus in advanced disease stages. Recent pathophysiological research pointed to nigro-pontine networks entrained to locomotor integration. Stimulation of the pedunculopontine nucleus is currently under investigation, however, hitherto remains controversial. The substantia nigra pars reticulata (SNr)--entrained into integrative locomotor networks--is pathologically overactive in PD. High-frequent stimulation of the substantia nigra pars reticulata preferentially modulated axial symptoms and therefore is suggested as a novel therapeutic candidate target for neuromodulation of refractory gait disturbances in PD. METHODS: 12 patients with idiopathic Parkinson's disease and refractory gait disturbances under best individual subthalamic nucleus stimulation and dopaminergic medication will be enroled into this double-blind 2 x 2 cross-over clinical trial. The treatment consists of two different stimulation settings using (i) conventional stimulation of the subthalamic nucleus [STNmono] and (ii) combined stimulation of distant electrode contacts located in the subthalamic nucleus and caudal border zone of STN and substantia nigra pars reticulata [STN+SNr]. The primary outcome measure is the change of the cumulative 'axial score' (UPDRS II items '13-15' and UPRDS III items '27-31') at three weeks of constant stimulation in either condition. Secondary outcome measures include specific scores on freezing of gait, balance function, quality of life, non-motor symptoms, and neuropsychiatric symptoms. The aim of the present trial is to investigate the efficacy and safety of a three week constant combined stimulation on [STN+SNr] compared to [STNmono]. The results will clarify, whether stimulation on nigral contacts additional to subthalamic stimulation will improve therapeutic response of otherwise refractory gait disturbances in PD. TRIAL REGISTRATION: The trial was registered with the clinical trials register of http://www.clinicaltrials.gov (NCT01355835). [less ▲]

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See detailCombined stimulation of the substantia nigra pars reticulata and the subthalamic nucleus is effective in hypokinetic gait disturbance in Parkinson's disease.
Weiss, Daniel; Breit, Sorin; Wachter, Tobias et al

in Journal of neurology (2011), 258(6), 1183-5

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See detailCentral oscillators in a patient with neuropathic tremor: evidence from intraoperative local field potential recordings.
Weiss, Daniel; Govindan, Rathinaswamy B.; Rilk, Albrecht et al

in Movement disorders : official journal of the Movement Disorder Society (2011), 26(2), 323-7

Present pathophysiological concepts of neuropathic tremor assume mistimed and defective afferent input resulting in deregulation of cerebello-thalamo-cortical motor networks. Here, we provide direct ... [more ▼]

Present pathophysiological concepts of neuropathic tremor assume mistimed and defective afferent input resulting in deregulation of cerebello-thalamo-cortical motor networks. Here, we provide direct evidence of central tremor processing in a 76-year-old female who underwent bilateral deep brain stimulation of the ventral intermedial nucleus of the thalamus (Vim-DBS) because of neuropathic tremor associated with IgM paraproteinemia. Electrophysiological recordings of EEG and EMG were performed in three perioperative sessions: (1) preoperatively, (2) intraoperatively, and (3) 4 days after surgery in both rest and postural tremor conditions. Tremor-related synchronization (coherence) between motor cortex (M1) and muscles (M. extensor digitorum, M. flexor digitorum) was assessed, and additional intraoperative local field potential (LFP) recordings from Vim allowed comprehensive coherence mapping in thalamo-cortico-muscular networks. Directionality of information flow was determined by directed transfer function (DTF) and phase analyses. Stimulation effects on tremor and corticomuscular coherence were assessed and the patient was followed for 12 months on clinical outcome measures (Tremor Rating Scale, CADET-Score). Vim-DBS reduced tremor (59%) and improved motor functionality in daily activities (31%, CADET-A) after 12 months. Intraoperative recordings demonstrated significant coherence in the tremor frequency (4 Hz) between M1 and contralateral muscle, Vim and ipsilateral M1, Vim and contralateral muscle, but not between Vim and contralateral M1. Information flow was directed from M1 to Vim and bidirectional between M1 and muscle and between Vim and muscle, respectively. Corticomuscular coherence at tremor frequency was completely suppressed by Vim-DBS. Our case study demonstrates central oscillators underlying neuropathic tremor and implies a strong pathophysiological rationale for Vim-DBS. [less ▲]

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See detailEffects of subthalamic nucleus stimulation on emotional prosody comprehension in Parkinson's disease.
Bruck, Carolin; Wildgruber, Dirk; Kreifelts, Benjamin et al

in PloS one (2011), 6(4), 19140

BACKGROUND: Although impaired decoding of emotional prosody has frequently been associated with Parkinson's disease (PD), to date only few reports have sought to explore the effect of Parkinson's ... [more ▼]

BACKGROUND: Although impaired decoding of emotional prosody has frequently been associated with Parkinson's disease (PD), to date only few reports have sought to explore the effect of Parkinson's treatment on disturbances of prosody decoding. In particular, little is known about how surgical treatment approaches such as high frequency deep brain stimulation (DBS) affect emotional speech perception in patients with PD. Accordingly, the objective of this study was to evaluate the effect of subthalamic nucleus (STN) stimulation on prosody processing. METHODOLOGY/PRINCIPAL FINDINGS: To this end the performance of 13 PD patients on three tasks requiring the decoding of emotional speech was assessed and subsequently compared to the performance of healthy control individuals. To delineate the effect of STN-DBS, all patients were tested with stimulators turned on as well as with stimulators turned off. Results revealed that irrespective of whether assessments were made "on" or "off" stimulation, patients' performance was less accurate as compared to healthy control participants on all tasks employed in this study. However, while accuracy appeared to be unaffected by stimulator status, a facilitation of reactions specific to highly conflicting emotional stimulus material (i.e. stimulus material presenting contradicting emotional messages on a verbal and non-verbal prosodic level) was observed during "on" stimulation assessments. CONCLUSION: In sum, presented results suggest that the processing of emotional speech is indeed modulated by STN-DBS. Observed alterations might, on the one hand, reflect a more efficient processing of highly conflicting stimulus material following DBS. However, on the other hand, given the lack of an improvement in accuracy, increased impulsivity associated with STN stimulation needs to be taken into consideration. [less ▲]

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See detailInvoluntary eyelid closure after STN-DBS: evidence for different pathophysiological entities.
Weiss, Daniel; Wachter, Tobias; Breit, Sorin et al

in Journal of neurology, neurosurgery, and psychiatry (2010), 81(9), 1002-7

OBJECTIVE: Involuntary eyelid closure (IEC) may occur after deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson's disease (PD) and is often categorised as apraxia of lid opening (ALO ... [more ▼]

OBJECTIVE: Involuntary eyelid closure (IEC) may occur after deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson's disease (PD) and is often categorised as apraxia of lid opening (ALO), albeit the appropriateness of this term is under debate. To gain insight into the hitherto undefined pathophysiology of IEC after STN-DBS, we performed a comprehensive clinical and electrophysiological characterisation of lid function in a total of six PD patients. METHODS: The study was carried out in six PD patients who developed IEC after STN-DBS. They underwent neurological examination and electromyography recording of activity in the orbicularis oculi muscle (OO) upon varying stimulation patterns. Intraoperative studies were performed in one patient. RESULTS: Increasing STN-DBS intensity induced IEC in four patients, whereas it improved the condition in two. Needle EMG showed tonic hyperactivity of the OO in STN-DBS induced IEC, while variable patterns of OO activity (irregular and tonic) were seen in patients with STN-DBS-relieved IEC. Intraoperative analysis in one patient showed evidence for IEC being induced by activation of corticobulbar fibres. CONCLUSIONS: We identified two groups of IEC after STN-DBS based on clinical and EMG patterns: (1) STN-DBS induced IEC associated with tonic OO overactivity and (2) STN-DBS relieved IEC presenting with variable EMG patterns. Our findings provide relevant information on pathophysiology of STN-DBS related IEC and implications for its therapeutic management. [less ▲]

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See detailSevere muscular fasciculations as an uncommon side-effect due to microdefect of an extension wire in deep brain stimulation.
Wachter, Tobias; Weiss, Daniel; Breit, Sorin et al

in Movement disorders : official journal of the Movement Disorder Society (2009), 24(14), 2161-2

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See detailSustained improvement of obsessive-compulsive disorder by deep brain stimulation in a woman with residual schizophrenia.
Plewnia, Christian; Schober, Franziska; Rilk, Albrecht et al

in The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP) (2008), 11(8), 1181-3

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