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161 result(s) for "Weber, Wim"
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Evaluation of editors’ abilities to predict the citation potential of research manuscripts submitted to The BMJ: a cohort study
AbstractObjectiveTo evaluate the ability of The BMJ editors to predict the number of times submitted research manuscripts will be cited.DesignCohort study.SettingManuscripts submitted to The BMJ, reviewed, and subsequently scheduled for discussion at a prepublication meeting between 27 August 2015 and 29 December 2016.Participants10 BMJ research team editors.Main outcome measuresReviewed manuscripts were rated independently by attending editors for citation potential in the year of first publication plus the next year: no citations, below average (<10 citations), average (10-17 citations), or high (>17 citations). Predicted citations were subsequently compared with actual citations extracted from Web of Science (WOS).ResultsOf 534 manuscripts reviewed, 505 were published as full length articles (219 in The BMJ) by end of 2019 and indexed in WOS, 22 were unpublished, and one abstract was withdrawn. Among the 505 manuscripts, the median (IQR [range]) number of citations in the year of publication plus the following year was 9 (4-17 [0-150]); 277 (55%) manuscripts were cited <10 times, 105 (21%) were cited 10-17 times, and 123 (24%) cited >17 times. Manuscripts accepted by The BMJ were cited more highly (median 12 (IQR 7-24) citations) than those rejected (median 7 (3-12) citations). For all 10 editors, predicted ratings tended to increase in line with actual citations, but with considerable variation within categories; nine failed to identify the correct citation category for >50% (range 31%-52%) of manuscripts, and κ ranged between 0.01 to 0.19 for agreement between predicted and actual categories. Editors more often rated papers that achieved high actual citation counts as having low citation potential than the reverse. Collectively, the mean percentage of editors predicting the correct citation category was 43%, and for 160 (32%) manuscripts at least 50% of editors predicted the right category.ConclusionsEditors weren’t good at estimating the citation potential of manuscripts individually or as a group; there is no wisdom of the crowd when it comes to BMJ editors.
An fMRI study into emotional processing in Parkinson’s disease: Does increased medial prefrontal activation compensate for striatal dysfunction?
Apart from a progressive decline of motor functions, Parkinson's disease (PD) is also characterized by non-motor symptoms, including disturbed processing of emotions. This study aims at assessing emotional processing and its neurobiological correlates in PD with the focus on how medicated Parkinson patients may achieve normal emotional responsiveness despite basal ganglia dysfunction. Nineteen medicated patients with mild to moderate PD (without dementia or depression) and 19 matched healthy controls passively viewed positive, negative, and neutral pictures in an event-related blood oxygen level-dependent functional magnetic resonance imaging study (BOLD-fMRI). Individual subjective ratings of valence and arousal levels for these pictures were obtained right after the scanning. Parkinson patients showed similar valence and arousal ratings as controls, denoting intact emotional processing at the behavioral level. Yet, Parkinson patients showed decreased bilateral putaminal activation and increased activation in the right dorsomedial prefrontal cortex (PFC), compared to controls, both most pronounced for highly arousing emotional stimuli. Our findings revealed for the first time a possible compensatory neural mechanism in Parkinson patients during emotional processing. The increased medial PFC activity may have modulated emotional responsiveness in patients via top-down cognitive control, therewith restoring emotional processing at the behavioral level, despite striatal dysfunction. These results may impact upon current treatment strategies of affective disorders in PD as patients may benefit from this intact or even compensatory influence of prefrontal areas when therapeutic strategies are applied that rely on cognitive control to modulate disturbed processing of emotions.
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Deterioration of Parkinson's disease during hospitalization: survey of 684 patients
Background A substantial fraction of Parkinson's disease patients deteriorate during hospitalisation, but the precise proportion and the reasons why have not been studied systematically and the focus has been on surgical wards and on Accident & Emergency departments. We assessed the prevalence and risk factors of deterioration of Parkinson's disease symptoms during hospitalization, including all wards. Methods We invited Parkinson's disease patients from three neurology departments in The Netherlands to answer a standardised questionnaire on general, disease and hospital related issues. Patients who had been hospitalized in the previous year were included and analysed. Possible risk factors for Parkinson's disease deterioration were identified. Proportions were analysed using the Chi-Square test and a logistic regression analysis was performed. Results Eighteen percent of 684 Parkinson's disease patients had been hospitalized at least once in the last year. Twenty-one percent experienced deterioration of motor symptoms, 33% did have one or more complications and 26% had received incorrect anti-Parkinson's medication. There were no statistically significant differences for these variables between admissions on neurologic or non-neurologic wards and between having surgery or not. Incorrect medication during hospitalization was significantly associated with higher risk (OR 5.8, CI 2.5-13.7) of deterioration, as were having infections (OR 6.7 CI 1.8-24.7). A higher levodopa equivalent dose per day was a significant risk factor for deterioration. When adjusting for different variables, wrong medication distribution was the most important risk factor for deterioration. Conclusions Incorrect medication and infections are the important risk factors for deterioration of Parkinson's disease patients both for admissions with and without surgery and both for admissions on neurologic and non-neurologic wards. Measures should be taken to improve care and incorporated in guidelines.
Specificity and sensitivity of transcranial sonography of the substantia nigra in the diagnosis of Parkinson's disease: prospective cohort study in 196 patients
Objective Numerous ultrasound studies have suggested that a typical enlarged area of echogenicity in the substantia nigra (SN+) can help diagnose idiopathic Parkinson's disease (IPD). Almost all these studies were retrospective and involved patients with well-established diagnoses and long-disease duration. In this study the diagnostic accuracy of transcranial sonography (TCS) of the substantia nigra in the patient with an undiagnosed parkinsonian syndrome of recent onset has been evaluated. Design Prospective cohort study for diagnostic accuracy. Setting Neurology outpatient clinics of two teaching hospitals in the Netherlands. Patients 196 consecutive patients, who were referred to two neurology outpatient clinics for analysis of clinically unclear parkinsonism. Within 2 weeks of inclusion all patients also underwent a TCS and a 123I-ioflupane Single Photon Emission CT (FP-CIT SPECT) scan of the brain (n=176). Outcome measures After 2 years, patients were re-examined by two movement disorder specialist neurologists for a final clinical diagnosis, that served as a surrogate gold standard for our study. Results Temporal acoustic windows were insufficient in 45 of 241 patients (18.67%). The final clinical diagnosis was IPD in 102 (52.0%) patients. Twenty-four (12.3%) patients were diagnosed with atypical parkinsonisms (APS) of which 8 (4.0%) multisystem atrophy (MSA), 6 (3.1%) progressive supranuclear palsy (PSP), 6 (3.1%) Lewy body dementia and 4 (2%) corticobasal degeneration. Twenty-one (10.7%) patients had a diagnosis of vascular parkinsonism, 20 (10.2%) essential tremor, 7 (3.6%) drug-induced parkinsonism and 22 (11.2%) patients had no parkinsonism but an alternative diagnosis. The sensitivity of a SN+ for the diagnosis IPD was 0.40 (CI 0.30 to 0.50) and the specificity 0.61 (CI 0.52 to 0.70). Hereby the positive predictive value (PPV) was 0.53 and the negative predictive value (NPV) 0.48. The sensitivity and specificity of FP-CIT SPECT scans for diagnosing IPD was 0.88 (CI 0.1 to 0.95) and 0.68 (CI 0.58 to 0.76) with a PPV of 0.75 and an NPV of 0.84. Conclusions The diagnostic accuracy of TCS in early stage Parkinson's disease is not sufficient for routine clinical use. Clinicaltrials.gov identifier NCT0036819
Transcranial sonography findings related to depression in parkinsonian disorders: cross-sectional study in 126 patients
Background. Transcranial sonography (TCS) has emerged as a potential diagnostic tool for Parkinson’s disease. Recent research has suggested that abnormal echogenicity of substantia nigra, raphe nuclei and third ventricle is associated with increased risk of depression among these patients. We sought to reproduce these findings in an ongoing larger study of patients with parkinsonian syndromes. Methods. A total of 126 patients with parkinsonian symptoms underwent the Hamilton Depression Scale, and TCS of the substantia nigra (SN) ( n = 126), the raphe nuclei (RN) ( n = 80) and the third ventricle ( n = 57). We then calculated the correlation between depression and hyper-echogenic SN, hypo-echogenic RN and a wider third ventricle. Results. In patients with PD we found no significant difference of the SN between non-depressed and depressed patients (46% vs. 22%; p = 0.18). Non-depressed patients with other parkinsonisms more often had hyperechogenicity of the SN than depressed patients (51% vs. 0%; p = 0.01). We found no relation between depression and the echogenicity of the RN or the width of the third ventricle. Conclusions. In patients with parkinsonian syndromes, we found no association between depression and hyper-echogenic SN, hypo-echogenic RN or a wider third ventricle, as determined by transcranial sonography.
Transcranial duplex in the differential diagnosis of parkinsonian syndromes
Background Transcranial duplex scanning (TCD) of the substantia nigra (SN) is increasingly used to diagnose Idiopathic Parkinson’s Disease (IPD). Up until now 70 diagnostic studies have been published, not only on investigation of the SN, but also of the lenticular nucleus (LN) and the Raphe nuclei (RN). Method We systematically reviewed all diagnostic TCD studies in parkinsonian patients up to June 2008. Results We found 35 eligible studies. Of the 1534 IPD patients investigated in the 35 studies 200 (13 %) had an inconclusive SN-TCD. An increased echo-intensity of the SN was seen in 1167 (87 %) of the 1334 IPD patients, 276 (12 %) of the 2340 healthy controls and in 41 (30 %) of the 138 patients with an atypical parkinsonian syndrome (APS). On the contrary, a pathological LNTCD was found more often in APS patients (79 %) than in IPD patients (23 %) and healthy controls (6 %). A decreased echo-intensity of the RN was found more often in depressed (46 %) than in non-depressed IPD patients (16 %). Conclusions SN-TCD accurately differentiates between patients with IPD and healthy controls, but not between patients with IPD and APS. LN-TCD is only moderate accurate to delineate IPD from APS, but combinations of SN- and LN-TCD may be more promising. RN-TCD has only marginal diagnostic accuracy in diagnosing depression in IPD and non-IPD patients. Before TCD can be implicated, more research is needed to standardize the TCD technique, to investigate the TCD in non-research settings and to determine the additional value of TCD compared with currently used clinical techniques like SPECT imaging.
Abnormal Echogenicity of the Substantia Nigra, Raphe Nuclei, and Third-Ventricle Width as Markers of Cognitive Impairment in Parkinsonian Disorders: A Cross-Sectional Study
Background. Patients with Parkinson’s disease (PD) have a high risk of cognitive problems. Objective. This study assesses whether abnormal echogenicity of the substantia nigra (SN) and raphe nuclei (RN) and the diameter of third ventricle are markers of cognitive impairment in patients with PD and other forms of parkinsonism. Methods. 126 outpatients with early signs of parkinsonism underwent transcranial sonography (TCS). The scales for the outcome of Parkinson’s disease cognition (SCOPA-COG) were used as cognitive measure. Definite neurological diagnosis was established after two-year follow-up. Results. One-third of the patients with PD and half of those with APS had signs of cognitive impairment. The echogenicity of the SN was not related to cognitive impairment. The diameter of the third ventricle was significantly larger in PD patients with cognitive impairment compared to those without. In patients with APS we found a significantly higher frequency of hypoechogenic RN in patients with cognitive problems. Conclusions. Cognitive impairment is already present in a substantial proportion of patients with PD and APS at first referral. In patients with APS the frequency of hypoechogenic RN points to the direction of other pathophysiology with more emphasis on deficits in the serotonergic neurotransmitter system. The larger diameter of the third ventricle in PD patients with cognitive impairment may reflect Alzheimer like brain atrophy, as has been reported in earlier studies.
Neurologists’ diagnostic accuracy of depression and cognitive problems in patients with parkinsonism
Background Depression and cognitive impairment (CI) are important non-motor symptoms in Parkinson’s Disease (PD) and related syndromes, but it is not clear how well they are recognised in daily practice. We have studied the diagnostic performance of experienced neurologists on the topics depression and cognitive impairment during a routine encounter with a patient with recent-onset parkinsonian symptoms. Methods Two experienced neurologists took the history and examined 104 patients with a recent-onset parkinsonian disorder, and assessed the presence of depression and cognitive impairment. On the same day, all patients underwent a Hamilton Depression Rating Scale test, and a Scales for Outcomes in Parkinson’s Disease-Cognition-test (SCOPA-COG). Results The sensitivity of the neurologists for the topic depression was poor: 33.3%. However, the specificity varied from 90.8 to 94.7%. The patients’ sensitivity was higher, although the specificity was lower. On the topic CI, the sensitivity of the neurologists was again low, in a range from 30.4 up to 34.8%: however the specificity was high, with 92.9%. The patients’ sensitivity and specificity were both lower, compared to the number of the neurologists. Conclusions Neurologists’ intuition and clinical judgment alone are not accurate for detection of depression or cognitive impairment in patients with recent-onset parkinsonian symptoms because of low sensitivity despite of high specificity. Trial registration (ITRSCC)NCT0036819.
Diffuse large B-cell lymphoma of the cauda equina
Primary central nervous system (CNS) lymphoma is a rare form of non-Hodgkin's lymphoma. The clinical presentation is variable, depending on its localisation within the nervous system. Only 1% of primary CNS lymphoma emerges in the spinal cord, and the prevalence of primary lymphoma of the cauda equina is unknown, but probably even rarer. Diagnosing primary lymphoma of the cauda equina is difficult, since it can mimic other more common disorders such as a herniated disc, especially in its early stages. Here we present two cases of primary cauda equina lymphoma in which diagnostic work up took a long time, as the final diagnosis was only reached after a nerve root biopsy.