32 research outputs found
International Class Action Settlements in the Netherlands since Converium
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International Class Action Settlements in the Netherlands since Converium
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Randomized Delayed-Start Trial of Levodopa in Parkinson's Disease
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201287.pdf (publisher's version ) (Open Access
SERT-to-DAT ratios in early Parkinson's disease do not correlate with the development of dyskinesias
BACKGROUND: Although the treatment of Parkinson’s disease (PD) is very effective, in the course of the disease, 40% to 60% of patients develop dyskinesias. The pathophysiology of dyskinesias is still unclear. Results of preclinical research suggest that uptake and uncontrolled release of dopamine by serotonergic neurons is an important factor. Based on this model, we hypothesized that dyskinesias will develop predominantly in PD patients with a relatively preserved serotonergic system. METHODS: Between 1995 and 1998, 50 patients with early-stage untreated PD, diagnosed according to clinical criteria, and reduced striatal [(123)I]β-carboxymethyoxy-3-beta-(4-iodophenyl) tropane (CIT) single-photon emission computed tomography (SPECT) binding were recruited. To test our hypothesis, we retrospectively assessed baseline [(123)I]β-CIT SPECT scans for striatal dopamine transporter (DAT) and midbrain serotonin transporter (SERT) availability as well as the SERT-to-DAT ratios. We compared these data between patients that developed dyskinesias and patients that did not develop dyskinesias during a mean follow-up of 14.2 years. RESULTS: Approximately half of the PD patients developed dyskinesias. No differences in baseline [(123)I]β-CIT DAT availability, SERT availability, or SERT-to-DAT ratios were found between the dyskinetic and non-dyskinetic group. The development of dyskinesias was most strongly associated with the age of onset (P = 0.002). CONCLUSIONS: SERT-to-DAT ratios in early-stage untreated PD do not correlate with the future development of dyskinesias. However, our study does not exclude the possibility that SERT-to-DAT ratios increase with disease progression in patients that develop dyskinesias because of a slower rate of degeneration of the serotonergic system
The cerebral tremor circuit in a patient with Holmes tremor
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229762.pdf (publisher's version ) (Open Access)The cerebral network associated with Holmes tremor has never been determined directly. A previous study reported a brain network that is functionally connected, in healthy individuals, to different lesions that cause Holmes tremor (lesion connectome). We report a 71-year-old man with severe left-sided tremor caused by a microbleed near the right red nucleus. Using accelerometry-fMRI, we show tremor-related activity in contralateral sensorimotor cortex and cerebellar vermis. This network was distinct from, but functionally coupled to, the Holmes lesion connectome. We propose that Holmes tremor involves three distinct cerebral mechanisms: a structural lesion, an intermediate lesion connectome, and symptom-related activity
Orthostatic Hypotension in Parkinson's Disease: The Relation of Blood Pressure Tests and Symptoms in Daily Life
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Protocol of a randomised delayed-start double-blind placebo-controlled multi-centre trial for Levodopa in EArly Parkinson's disease: the LEAP-study
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152630.pdf (publisher's version ) (Open Access)BACKGROUND: The aim of this study is to investigate if early treatment with levodopa has a beneficial disease modifying effect on Parkinson's disease (PD) symptoms and functional health, improves the ability to (maintain) work, and reduces the use of (informal) care, caregiver burden, and costs. Additionally, cost-effectiveness and cost-utility of early levodopa treatment will be assessed. METHODS: To differentiate between the direct symptomatic effects and possible disease modifying effects of levodopa, we use a randomised delayed-start double-blind placebo-controlled multi-centre trial design. Patients with early stage PD whose functional health does not yet necessitate initiation of PD-medication will be randomised to either 40 weeks of treatment with levodopa/carbidopa 100/25 mg TID including 2 weeks of dose escalation or to 40 weeks placebo TID. Subsequently, all patients receive levodopa/carbidopa 100/25 mg TID for 40 weeks. There are 8 assessments: at baseline and at 4, 22, 40, 44, 56, 68, and 80 weeks. The primary outcome measure is the difference in the mean total Unified Parkinson's Disease Rating Scale scores between the early- and delayed-start groups at 80 weeks. Secondary outcome measures are rate of progression, the AMC Linear Disability Score, side effects, perceived quality of life with the Parkinson's Disease Questionnaire-39, the European Quality of Life-5 Dimensions (EQ-5D), ability to (maintain) work, the use of (informal) care, caregiver burden, and costs. 446 newly diagnosed PD patients without impaired functional health need to be recruited in order to detect a minimal clinical relevant difference of 4 points on the total UPDRS at 80 weeks. DISCUSSION: The LEAP-study will provide insights into the possible disease modifying effects of early levodopa. TRIAL REGISTRATION: ISRCTN30518857 , EudraCT number 2011-000678-72
Can We Rely on Susceptibility-Weighted Imaging for Subthalamic Nucleus Identification in Deep Brain Stimulation Surgery?
Neurological Motor Disorder
Tremor-specific neuronal oscillation pattern in dorsal subthalamic nucleus of parkinsonian patients
BackgroundSubthalamic nucleus (STN) deep brain stimulation effectively improves parkinsonian symptoms. It is hypothesized that distinct functional territories with different neurophysiologic activity within the STN relate to different symptoms.ObjectiveThe aim of the study was to identify distinctive characteristics of STN neuronal activity related to tremor by directly comparing tremor sides with no-tremor sides. In addition, we studied the spatial pattern of frequency distributions within the STN in more detail.MethodsWe analyzed intraoperative STN single/multiunit recordings from 33 tremor sides and 23 no-tremor sides. STN tracks were normalized to a length of 1 and subdivided into eight successive layers. The power spectral density was split into six frequency bands: theta (3-8 Hz), alpha (9-12 Hz), lower beta (13-20 Hz), upper beta (21-30 Hz), lower gamma (31-59 Hz), and upper gamma (60-100 Hz).ResultsTremor sides presented predominant theta frequency oscillations in the most dorsal layers of the STN, whereas in no-tremor sides beta frequencies predominated. Oscillatory activity was stronger in the dorsal STN than in the ventral, and this pattern was specific for frequencies in the theta, alpha, and beta bands, but not in the gamma bands.ConclusionsOur study supports the hypothesis that the presence of tremor is associated with a distinctive neuronal oscillations pattern. In particular, we demonstrate the specificity of the association of theta frequencies in the dorsal STN with tremor. Identification of symptom-specific characteristics of intraoperative microrecordings in the STN may lead to refinement of targeting for each patient, tailored to the specific clinical presentation. (C) 2012 Elsevier Inc. All rights reserved.Neurological Motor Disorder