Publications by authors named "Daniela Falk"

Alongside stereotactic magnetic resonance imaging, microelectrode recording (MER) is frequently used during the deep brain stimulation (DBS) surgery for optimal target localization. The aim of this study is to optimize subthalamic nucleus (STN) mapping using MER analytical patterns. 16 patients underwent bilateral STN-DBS.

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Background: Programming deep brain stimulation in dystonia is difficult because of the delayed benefits and absence of evidence-based guidelines. Therefore, we evaluated the efficacy of a programming algorithm applied in a double-blind, sham-controlled multicenter study of pallidal deep brain stimulation in dystonia.

Methods: A standardized monopolar review to identify the contact with the best acute antidystonic effect was applied in 40 patients, who were then programmed 0.

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Objective: Generators implanted for deep brain stimulation must be replaced after several years. If a Kinetra generator is replaced by the Activa-PC, an adaptor will be required to attach it to the original extension cables. On the basis of our clinical impression that the battery life of the Active-PC generator was shorter when an adaptor was used, we performed this retrospective study.

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Deep brain stimulation (DBS) is an established treatment for various movement disorders. There is little data available about the potential damage to brain parenchyma through DBS treatment. The objective of this study was to investigate the occurrence of signal changes on magnetic resonance imaging (MRI) in patients treated with DBS.

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Introduction: Growing evidence suggests that pallidal deep brain stimulation represents a potential new therapeutic avenue in tardive dystonia/dyskinesia, but controlled and blinded randomized studies (RCT) are missing. The present RCT compares dystonia/dyskinesia severity of pallidal neurostimulation in patients with tardive dystonia using a delayed-start design paradigm.

Methods: Dystonia/dyskinesia severity was assessed via blinded videos following pallidal neurostimulation at 3 (blinded phase) and 6 months (open extension phase).

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Background: Nonrechargeable deep brain stimulation impulse generators (IGs) with low or empty battery status require surgical IG exchange several years after initial implantation. The aim of this study was to investigate complication rates after IG exchange surgery and identify risk factors.

Methods: We retrospectively analyzed complications following IG exchange surgery from 2008 to 2015 in our department.

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Objective: Nonrechargeable deep brain stimulation (DBS) generators must be replaced when the battery capacity is exhausted. Battery life depends on many factors and differs between generator models. A new nonrechargeable generator model replaced the previous model in 2008.

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The aim of the study was to record movement-related single unit activity (SUA) in the human subthalamic nucleus (STN) during a standardized motor task of the upper limb. We performed microrecordings from the motor region of the human STN and registered kinematic data in 12 patients with Parkinson's disease (PD) undergoing deep brain stimulation surgery (seven women, mean age 62.0 ± 4.

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Background: The threshold current for inducing muscle contractions by stimulation of pyramidal tract fibres adjacent to the globus pallidus internus (GPi) is, besides microelectrode recordings for the determination of nuclear boundaries, currently the only neurophysiological marker for intraoperative refinement of the anatomically planned target point for pallidal deep brain stimulation (GPi-DBS) in dystonia.

Objectives: To determine the relationship between intraoperative thresholds for muscle contractions under general anaesthesia and postoperative thresholds in GPi-DBS.

Methods: Intraoperatively, current amplitude thresholds (120 µs, 130 Hz) were determined in 6 dystonic patients under general anaesthesia (through the uninsulated tip of the microelectrode guide tube).

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Background: Deep brain stimulation (DBS) in therapy for advanced Parkinson's disease (PD) is an accepted treatment. Infections of the system and other complications occasionally result in hardware removal and subsequent medical treatment alone for months.

Methods: We have analyzed the clinical course of 15 patients requiring removal of at least parts of the DBS system, resulting in a cessation of stimulation.

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Background: Subthalamic deep brain stimulation (STN-DBS) can ameliorate gait disturbances in Parkinson's disease (PD). Using motor imagery and positron emission tomography (PET), we investigated how STN-DBS interacts with supraspinal locomotor centers in PD.

Methods: Ten PD patients with bilateral STN-DBS actually walked or stood still under STN-DBS ON or OFF conditions.

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Background: Cervical dystonia is managed mainly by repeated botulinum toxin injections. We aimed to establish whether pallidal neurostimulation could improve symptoms in patients not adequately responding to chemodenervation or oral drug treatment.

Methods: In this randomised, sham-controlled trial, we recruited patients with cervical dystonia from centres in Germany, Norway, and Austria.

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Postural tremor is the leading symptom in essential tremor, but in some cases intention tremor and limb ataxia emerge and can become highly disabling features. Deep brain stimulation of the thalamus or subthalamic white matter improve tremor and ataxia; however, the underlying network mechanisms are enigmatic. To elucidate the mechanisms of deep brain stimulation in essential tremor, we pursued a multimodal approach combining kinematic measures of reach-to-grasp movements, clinical assessments, physiological measures of neuronal excitability and probabilistic tractography from diffusion tensor imaging.

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Background: Deep brain stimulation of the internal pallidum (GPi-DBS) is effective for various types of drug-refractory primary dystonias. Rare clinical forms as dystonic camptocormia may profit but available data are scarce.

Methods: We here report on a retrospective clinical assessment of three patients with primary dystonic camptocormia treated with GPi-DBS.

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Spatial attention is a lateralized feature of the human brain. Whereas the role of cortical areas of the nondominant hemisphere on spatial attention has been investigated in detail, the impact of the BG, and more precisely the subthalamic nucleus, on signs and symptoms of spatial attention is not well understood. Here we used unilateral deep brain stimulation of the subthalamic nucleus to reversibly, specifically, and intraindividually modify the neuronal BG outflow and its consequences on signs and symptoms of visuospatial attention in patients suffering from Parkinson disease.

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Deep brain stimulation of the subthalamic nucleus improves motor functions in patients suffering from advanced Parkinson's disease but in some patients, it is also associated with a mild decline in cognitive functioning about one standard deviation from the preoperative state. We assessed the impact of the cortical lead entry point, the subcortical electrode path and the position of the active electrode contacts on neuropsychological changes after subthalamic nucleus-deep brain stimulation compared to a control group of patients receiving best medical treatment. Sixty-eight patients with advanced Parkinson's disease were randomly assigned to have subthalamic nucleus-deep brain stimulation or best medical treatment for Parkinson's disease.

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Following the hypothesis that thalamic deep brain stimulation improves ataxia in patients with essential tremor by modulating the cerebello-thalamo-cortical pathway, we examined the joint kinematics of lower limbs during uninterrupted gait in eleven patients who have been treated with bilateral thalamic stimulation for 24.7±20.3 months.

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High-frequency stimulation of the subthalamic nucleus (STN-HFS) is highly effective in treating motor symptoms in Parkinson's disease (PD) and medication side effects as well as in improving quality of life. Despite preoperative screening for patients as eligible candidates for this treatment, electrode position may furthermore influence treatment quality. Here, we investigated the relationship between the anatomical site of stimulation within the MRI-defined STN and the outcome of PD patients after STN-HFS.

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Background: The improvement of PD motor symptoms by DBS of the STN depends on exact targeting.

Methods: A combination of MRI and multitrajectory microrecordings was used for localization of the STN in a group of 228 consecutive PD patients.

Results: In 1% of our cases, the STN was consistently shifted in the anterior (3.

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The effect of subthalamic deep brain stimulation on gait coordination and freezing of gait in patients with Parkinson's disease is incompletely understood. The purpose of this study was to investigate the extent to which modulation of symmetry and coordination between legs by subthalamic deep brain stimulation alters the frequency and duration of freezing of gait in patients with Parkinson's disease. We recruited 13 post-subthalamic deep brain stimulation patients with Parkinson's disease with off freezing of gait and evaluated them in the following 4 conditions: subthalamic deep brain stimulation on (ON) and stimulation off (OFF), 50% reduction of stimulation voltage for the leg with shorter step length (worse side reduction) and for the leg with longer step length (better side reduction).

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Deep brain stimulation of the globus pallidus internus (GPi DBS) is effective in the treatment of primary segmental and generalized dystonia. Although limb, neck, or truncal dystonia are markedly improved, orofacial dystonia is ameliorated to a lesser extent. Nevertheless, several case reports and small cohort studies have described favorable short-term results of GPi DBS in patients with severe Meige syndrome.

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