Publications by authors named "Allert N"

Background: Fear of progression (FoP) is a reactive, conscious concern about chronic disease progression and its consequences which may limit quality of life substantially. Only one study has examined FoP in Parkinson's disease (PD), showing the second highest FoP scores among chronic diseases.

Objective: To examine FoP prevalence and to exploratorily analyze determinants of FoP in PD.

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Music-assisted treadmill training (MATT) is a new therapeutic approach for Parkinson's disease (PD) patients, combining treadmill training with rhythmic auditory cueing and visual feedback. PD studies have shown larger positive effects on motor outcomes than usual treadmill training. However, effects on cognition, in contrast, are less clear.

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We report on a patient with thalamic deep brain stimulation (DBS) for essential tremor who was admitted to a stroke unit with transient vertigo, dysarthria, and gait disturbance. Transient ischemic attacks were assumed but fluctuating neurological symptoms persisted until presentation to a DBS center. Here, unstable high monopolar impedances of the right-hemispheric electrode contacts were detected.

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Open and short circuits of electrode contacts are important technical dysfunctions of DBS. Here, we report on another type of dysfunction restricted to a single electrode contact: impedance instability within regular absolute values. After 9-year subthalamic DBS, a Parkinson patient developed unilateral motor symptoms and intermittent dysaesthesia due to impedance instability of the active contact.

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Objective: To evaluate deep brain stimulation (DBS) of the posterior subthalamic area (PSA) in essential tremor (ET) and compare it to the ventral intermediate nucleus of the thalamus (VIM) in terms of stimulation efficacy, efficiency, and side effects.

Methods: DBS leads were implanted such that contacts were placed in the VIM, on the intercommissural line, and in the PSA. Thirteen patients with ET entered a randomized, double-blind crossover phase and completed a 1-year follow-up.

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Objectives: To evaluate the long-term course of quadripolar DBS electrodes with disconnected single contacts that cannot be used for DBS.

Materials And Methods: Quadripolar electrodes with open circuits of single contacts or monopolar impedances >6500 Ω were identified from a cohort of 2082 electrodes from 1044 patients with variable movement disorders. The long-term course was analyzed from follow-up data.

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Deep brain stimulation (DBS) is a highly efficient, evidence-based therapy for a set of neurological and psychiatric conditions and especially movement disorders such as Parkinson's disease, essential tremor and dystonia. Recent developments have improved the DBS technology. However, no unequivocal algorithms for an optimized postoperative care exist so far.

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Objectives: To evaluate the long-term course of DBS electrodes with short-circuited contacts.

Materials And Methods: Electrodes with bipolar impedances below 150 Ω were identified from a cohort of 1044 patients with 2082 electrodes for variable movement disorders. The long-term course was analyzed from follow-up data.

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Introduction: Pallidal deep brain stimulation (GPi-DBS) is an effective therapy for isolated dystonia, but 10-20% of patients show improvement below 25-30%. We here investigated causes of insufficient response to GPi-DBS in isolated dystonia in a cross-sectional study.

Methods: Patients with isolated dystonia at time of surgery, and <30% improvement on the Burke-Fahn-Marsden dystonia-rating-scale (BFMDRS) after ≥6 months of continuous GPi-DBS were videotaped ON and OFF stimulation, and history, preoperative videos, brain MRI, medical records, stimulation settings, stimulation system integrity, lead location, and genetic information were obtained and reviewed by an expert panel.

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Background: Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) is performed to suppress medically-resistant essential tremor (ET). However, stimulation induced dysarthria (SID) is a common side effect, limiting the extent to which tremor can be suppressed. To date, the exact pathogenesis of SID in VIM-DBS treated ET patients is unknown.

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Technical dysfunctions have been reported reducing efficacy of deep brain stimulation (DBS). Here, we report on an essential-tremor patient in whom a short circuit in bipolar DBS resulted not only in unilateral loss of therapy but also in high current flow and thereby rapid decline of the impulse-generator battery voltage from 2.83 V a week before the event to 2.

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Background: Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of the thalamus is effective in medication refractory essential tremor (ET). In recent years, evidence has accumulated that the region ventral to the VIM, the posterior subthalamic area (PSA), might be an equally or even more effective target for electrode implantation. However, this evidence is primarily based on case series, cross-sectional observations, and retrospective data.

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We report on a Parkinson patient with motor fluctuations and dyskinesias in whom deep brain stimulation (DBS) of the subthalamic nucleus (STN) not only improved motor symptoms but also pre-existing arachnophobia. Arachnophobia had been unchanged by the course of Parkinson's disease but rapidly improved with STN-DBS. Both, motor effects and the improvement of arachnophobia were stable during 2 years follow-up.

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Background. Postural instability in Parkinson's disease (PD) increases the risk of falls and is not improved by pharmacological therapy. Objective.

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In 2005, a European expert panel developed and validated an electronic tool to support the appropriate referral of patients with Parkinson's disease (PD) for the consideration of deep brain stimulation (DBS). Since new evidence has become available over the last decade an update of the tool is necessary. A world-wide expert panel (71 neurologists and 11 neurosurgeons) used the RAND/UCLA Appropriateness Method to assess the appropriateness of referral for 1296 scenarios (9-point scale).

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Background: High-frequency deep brain stimulation (DBS) with a single electrical source is effective for motor symptom relief in patients with Parkinson's disease. We postulated that a multiple-source, constant-current device that permits well defined distribution of current would lead to motor improvement in patients with Parkinson's disease.

Methods: We did a prospective, multicentre, non-randomised, open-label intervention study of an implantable DBS device (the VANTAGE study) at six specialist DBS centres at universities in six European countries.

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Focal lesions of brainstem, thalamus, and subcortical white matter may cause movement disorders that are clinically indistinguishable from cerebellar symptoms. It is suspected that ataxia in these cases is due to damage of efferent or afferent pathways of the cerebellum. However, the precise anatomical correlate often remains undefined.

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Objective: To identify the utilization and general acceptance of switching between predefined stimulation groups in essential tremor (ET) patients treated with deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of the thalamus.

Methods: Thirty-eight patients treated with VIM-DBS completed a telephone survey. This was designed to identify the general utilization of patient controllers and the specific usage of stimulation groups.

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Background: Deep brain stimulation alleviates tremor of various origins. Several regions like the ventralis intermediate nucleus of thalamus, the caudal zona incerta, and the posterior subthalamic region are generally targeted. Previous work with fiber tractography has shown the involvement of the cerebello-thalamo-cortical network in tremor control.

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Diffusion tensor imaging (DTI) is more than just a useful adjunct to invasive techniques like optogenetics which recently have tremendously influenced our understanding of the mechanisms of deep brain stimulation (DBS). In combination with other technologies, DTI helps us to understand which parts of the brain tissue are connected to others and which ones are truly influenced with neuromodulation. The complex interaction of DBS with the surrounding tissues-scrutinized with DTI-allows to create testable hypotheses that can explain network interactions.

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