Background and ObjectivesTo investigate CSF findings in relation to clinical and electrodiagnostic subtypes, severity, and outcome of Guillain-Barré syndrome (GBS) based on 1,500 patients in the... Show moreBackground and ObjectivesTo investigate CSF findings in relation to clinical and electrodiagnostic subtypes, severity, and outcome of Guillain-Barré syndrome (GBS) based on 1,500 patients in the International GBS Outcome Study.MethodsAlbuminocytologic dissociation (ACD) was defined as an increased protein level (>0.45 g/L) in the absence of elevated white cell count (<50 cells/μL). We excluded 124 (8%) patients because of other diagnoses, protocol violation, or insufficient data. The CSF was examined in 1,231 patients (89%).ResultsIn 846 (70%) patients, CSF examination showed ACD, which increased with time from weakness onset: ≤4 days 57%, >4 days 84%. High CSF protein levels were associated with a demyelinating subtype, proximal or global muscle weakness, and a reduced likelihood of being able to run at week 2 (odds ratio [OR] 0.42, 95% CI 0.25–0.70; p = 0.001) and week 4 (OR 0.44, 95% CI 0.27–0.72; p = 0.001). Patients with the Miller Fisher syndrome, distal predominant weakness, and normal or equivocal nerve conduction studies were more likely to have lower CSF protein levels. CSF cell count was <5 cells/μL in 1,005 patients (83%), 5–49 cells/μL in 200 patients (16%), and ≥50 cells/μL in 13 patients (1%).DiscussionACD is a common finding in GBS, but normal protein levels do not exclude this diagnosis. High CSF protein level is associated with an early severe disease course and a demyelinating subtype. Elevated CSF cell count, rarely ≥50 cells/μL, is compatible with GBS after a thorough exclusion of alternative diagnoses. Show less
Real, C. del; Busser, E. de; Berg, B. van den 2022
Background: Security by design is the approach to designing digital technologies that are foundationally secure. This approach has materialized in several software design methodologies. However, a... Show moreBackground: Security by design is the approach to designing digital technologies that are foundationally secure. This approach has materialized in several software design methodologies. However, a close examination of these methodologies shows that digital technologies security is designed as a technical feature, with no concern for their interaction with human, social, and organizational factors. This research argues that, in order to produce a design methodology for developing secure software systems that integrates non-technical factors in their design, an interdisciplinary and integrative review of the ‘security by design’ concept is needed. Objectives: The present protocol details the work plan for a systematic scoping review on security by design and related concepts. This review seeks to (1) synthesize current definitions of ‘security by design’, (2) elaborate a conceptual map that shows how ‘security by design’ connects to other related concepts, and (3) identify the key principles of the ‘security by design’ approach. Design: This systematic review follows the PRISMA extension for scoping review. Six databases are searched for thematically relevant studies published in English. Studies included peer-reviewed publications, government or company documents, technical reports, or a doctoral theses. After the initial search, three researchers will screen the title and abstracts following a screening tool. The consistency of researchers’ classification will be measured by calculating the inter-rater reliability. The reading of full texts will determine the final eligibility. Finally, data will be extracted from the final sample of documents. Show less
Background and ObjectivesThe clinical course and outcome of the Guillain-Barre syndrome (GBS) are diverse and vary among regions. The modified Erasmus GBS Outcome Score (mEGOS), developed with data... Show moreBackground and ObjectivesThe clinical course and outcome of the Guillain-Barre syndrome (GBS) are diverse and vary among regions. The modified Erasmus GBS Outcome Score (mEGOS), developed with data from Dutch patients, is a clinical model that predicts the risk of walking inability in patients with GBS. The study objective was to validate the mEGOS in the International GBS Outcome Study (IGOS) cohort and to improve its performance and region specificity.MethodsWe used prospective data from the first 1,500 patients included in IGOS, aged >= 6 years and unable to walk independently. We evaluated whether the mEGOS at entry and week 1 could predict the inability to walk unaided at 4 and 26 weeks in the full cohort and in regional subgroups, using 2 measures for model performance: (1) discrimination: area under the receiver operating characteristic curve (AUC) and (2) calibration: observed vs predicted probability of being unable to walk independently. To improve the model predictions, we recalibrated the model containing the overall mEGOS score, without changing the individual predictive factors. Finally, we assessed the predictive ability of the individual factors.ResultsFor validation of mEGOS at entry, 809 patients were eligible (Europe/North America [n = 677], Asia [n = 76], other [n = 56]), and 671 for validation of mEGOS at week 1 (Europe/North America [n = 563], Asia [n = 65], other [n = 43]). AUC values were >0.7 in all regional subgroups. In the Europe/North America subgroup, observed outcomes were worse than predicted; in Asia, observed outcomes were better than predicted. Recalibration improved model accuracy and enabled the development of a region-specific version for Europe/North America (mEGOS-Eu/NA). Similar to the original mEGOS, severe limb weakness and higher age were the predominant predictors of poor outcome in the IGOS cohort.DiscussionmEGOS is a validated tool to predict the inability to walk unaided at 4 and 26 weeks in patients with GBS, also in countries outside the Netherlands. We developed a region-specific version of mEGOS for patients from Europe/North America.Classification of EvidenceThis study provides Class II evidence that the mEGOS accurately predicts the inability to walk unaided at 4 and 26 weeks in patients with GBS. Show less
Berg, B. van den; Hijma, H.J.; Koopmans, I.; Doll, R.J.; Zuiker, R.G.J.A.; Groeneveld, G.J.; Buitenweg, J.R. 2022
Sleep deprivation has been shown to increase pain intensity and decrease pain thresholds in healthy subjects. In chronic pain patients, sleep impairment often worsens the perceived pain intensity.... Show moreSleep deprivation has been shown to increase pain intensity and decrease pain thresholds in healthy subjects. In chronic pain patients, sleep impairment often worsens the perceived pain intensity. This increased pain perception is the result of altered nociceptive processing. We recently developed a method to quantify and monitor altered nociceptive processing by simultaneous tracking of psychophysical detection thresholds and recording of evoked cortical potentials during intra-epidermal electric stimulation. In this study, we assessed the sensitivity of nociceptive detection thresholds and evoked potentials to altered nociceptive processing after sleep deprivation in an exploratory study with 24 healthy male and 24 healthy female subjects. In each subject, we tracked nociceptive detection thresholds and recorded central evoked potentials in response to 180 single- and 180 double-pulse intra-epidermal electric stimuli. Results showed that the detection thresholds for single- and double-pulse stimuli and the average central evoked potential for single-pulse stimuli were significantly decreased after sleep deprivation. When analyzed separated by sex, these effects were only significant in the male population. Multivariate analysis showed that the decrease of central evoked potential was associated with a decrease of task-related evoked activity. Measurement repetition led to a decrease of the detection threshold to double-pulse stimuli in the mixed and the female population, but did not significantly affect any other outcome measures. These results suggest that simultaneous tracking of psychophysical detection thresholds and evoked potentials is a useful method to observe altered nociceptive processing after sleep deprivation, but is also sensitive to sex differences and measurement repetition. Show less
While cyberspace has become central to all vital processes in our global economy and our social lives it also carries a wide variety of risks. Framing these risks is no easy feat: some lead to harm... Show moreWhile cyberspace has become central to all vital processes in our global economy and our social lives it also carries a wide variety of risks. Framing these risks is no easy feat: some lead to harm in cyberspace itself, while others lead to harm in the offline world as well. Moreover, sometimes harm is brought about intentionally, while at other times it may be the result of accidents. The ‘cyber harm model’ brings these challenges together, and provides us with an opportunity to get a comprehensive overview of the different types of incidents related to cyberspace. It also reveals where the biggest challenges for cyber crisis management lie and it provides us with a typology of different types of cyber crises that may arise. Cyber-induced crises have characteristics that make them hard to grapple with, for instance the fact that they can be induced remotely and instantaneously at multiple locations. Moreover, cyber crises are not always easily traceable, and sometimes it is difficult to see that the cause of a particular crisis in the offline world is an act in cyberspace. Finally, the borderless nature of cyberspace leads to potential large-scale geographical spread for cyber crises. Cyber crises also lead to a number of specific challenges for leadership, especially with respect to sense-making, meaning-making, decision-making, termination and learning. Show less
Kat, R.; Berg, B. van den; Perenboom, M.J.L.; Schenke, M.; Maagdenberg, A.M.J.M. van den; Bruining, H.; ... ; Kas, M.J.H. 2021
The mouse is widely used as an experimental model to study visual processing. To probe how the visual system detects changes in the environment, functional paradigms in freely behaving mice are... Show moreThe mouse is widely used as an experimental model to study visual processing. To probe how the visual system detects changes in the environment, functional paradigms in freely behaving mice are strongly needed. We developed and validated the first EEG-based method to investigate visual deviance detection in freely behaving mice. Mice with EEG implants were exposed to a visual deviant detection paradigm that involved changes in light intensity as standard and deviant stimuli. By subtracting the standard from the deviant evoked waveform, deviant detection was evident as bi-phasic negativity (starting around 70 ms) in the difference waveform. Additionally, deviance-associated evoked (beta/gamma) and induced (gamma) oscillatory responses were found. We showed that the results were stimulus-independent by applying a "flip-flop " design and the results showed good repeatability in an independent measurement. Together, we put forward a validated, easy-to-use paradigm to measure visual deviance processing in freely behaving mice. Show less
Walgaard, C.; Jacobs, B.C.; Lingsma, H.F.; Steyerberg, E.W.; Berg, B. van den; Doets, A.Y.; ... ; Dutch GBS Study Grp 2021
Background Treatment with one standard dose (2 g/kg) of intravenous immunoglobulin is insufficient in a proportion of patients with severe Guillain-Barre syndrome. Worldwide, around 25% of patients... Show moreBackground Treatment with one standard dose (2 g/kg) of intravenous immunoglobulin is insufficient in a proportion of patients with severe Guillain-Barre syndrome. Worldwide, around 25% of patients severely affected with the syndrome are given a second intravenous immunoglobulin dose (SID), although it has not been proven effective. We aimed to investigate whether a SID is effective in patients with Guillain-Barre syndrome with a predicted poor outcome.Methods In this randomised, double-blind, placebo-controlled trial (SID-GBS), we included patients (>= 12 years) with Guillain-Barre syndrome admitted to one of 59 participating hospitals in the Netherlands. Patients were included on the first day of standard intravenous immunoglobulin treatment (2 g/kg over 5 days). Only patients with a poor prognosis (score of >= 6) according to the modified Erasmus Guillain-Barre syndrome Outcome Score were randomly assigned, via block randomisation stratified by centre, to SID (2 g/kg over 5 days) or to placebo, 7-9 days after inclusion. Patients, outcome adjudicators, monitors, and the steering committee were masked to treatment allocation. The primary outcome measure was the Guillain-Barre syndrome disability score 4 weeks after inclusion. All patients in whom allocated trial medication was started were included in the modified intention-to-treat analysis.Findings Between Feb 16, 2010, and June 5, 2018, 327 of 339 patients assessed for eligibility were included. 112 had a poor prognosis. Of those, 93 patients with a poor prognosis were included in the modified intention-to-treat analysis: 49 (53%) received SID and 44 (47%) received placebo. The adjusted common odds ratio for improvement on the Guillain-Barre syndrome disability score at 4 weeks was 1.4 (95% CI 0.6-3.3; p=0.45). Patients given SID had more serious adverse events (35% vs 16% in the first 30 days), including thromboembolic events, than those in the placebo group. Four patients died in the intervention group (13-24 weeks after randomisation).Interpretation Our study does not provide evidence that patients with Guillain-Barre syndrome with a poor prognosis benefit from a second intravenous immunoglobulin course; moreover, it entails a risk of serious adverse events. Therefore, a second intravenous immunoglobulin course should not be considered for treatment of Guillain-Barre syndrome because of a poor prognosis. The results indicate the need for treatment trials with other immune modulators in patients severely affected by Guillain-Barre syndrome. Funding Prinses Beatrix Spierfonds and Sanquin Plasma Products. Copyright (C) 2021 Elsevier Ltd. All rights reserved. Show less
Peters, K.; Boogaard, G.; Berg, B. van den; Kalken, L. van 2020
Measuring altered nociceptive processing involved in chronic pain is difficult due to a lack of objective methods. Potential methods to characterize human nociceptive processing involve measuring... Show moreMeasuring altered nociceptive processing involved in chronic pain is difficult due to a lack of objective methods. Potential methods to characterize human nociceptive processing involve measuring neurophysiological activity and psychophysical responses to well-defined stimuli. To reliably measure neurophysiological activity in response to nociceptive stimulation using EEG, synchronized activation of nerve fibers and a large number of stimuli are required. On the other hand, to reliably measure psychophysical detection thresholds, selection of stimulus amplitudes around the detection threshold and many stimulus-response pairs are required. Combining the two techniques helps in quantifying the properties of nociceptive processing related to detected and non-detected stimuli around the detection threshold. The two techniques were combined in an experiment including 20 healthy participants to study the effect of intra-epidermal electrical stimulus properties (i.e. amplitude, single- or double-pulse and trial number) on the detection thresholds and vertex potentials. Generalized mixed regression and linear mixed regression were used to quantify the psychophysical detection probability and neurophysiological EEG responses, respectively. It was shown that the detection probability is significantly modulated by the stimulus amplitude, trial number, and the interaction between stimulus type and amplitude. Furthermore, EEG responses were significantly modulated by stimulus detection and trial number. Hence, we successfully demonstrated the possibility to simultaneously obtain information on psychophysical and neurophysiological properties of nociceptive processing. These results warrant further investigation of the potential of this method to observe altered nociceptive processing. Show less
Brinkman-Stoppelenburg, A.; Polinder, S.; Olij, B.F.; Berg, B. van den; Gunnink, N.; Hendriks, M.P.; ... ; Heide, A. van der 2019
Background Early palliative care team consultation has been shown to reduce costs of hospital care. The objective of this study was to investigate the association between palliative care team (PCT)... Show moreBackground Early palliative care team consultation has been shown to reduce costs of hospital care. The objective of this study was to investigate the association between palliative care team (PCT) consultation and the content and costs of hospital care in patients with advanced cancer. Material and Methods A prospective, observational study was conducted in 12 Dutch hospitals. Patients with advanced cancer and an estimated life expectancy of less than 1 year were included. We compared hospital care during 3 months of follow-up for patients with and without PCT involvement. Propensity score matching was used to estimate the effect of PCTs on costs of hospital care. Additionally, gamma regression models were estimated to assess predictors of hospital costs. Results We included 535 patients of whom 126 received PCT consultation. Patients with PCT had a worse life expectancy (life expectancy <3 months: 62% vs. 31%, p < .01) and performance status (p < .01, e.g., WHO status higher than 2:54% vs. 28%) and more often had no more options for anti-tumour therapy (57% vs. 30%, p < .01). Hospital length of stay, use of most diagnostic procedures, medication and other therapeutic interventions were similar. The total mean hospital costs were euro8,393 for patients with and euro8,631 for patients without PCT consultation. Analyses using propensity scores to control for observed confounding showed no significant difference in hospital costs. Conclusions PCT consultation for patients with cancer in Dutch hospitals often occurs late in the patients' disease trajectories, which might explain why we found no effect of PCT consultation on costs of hospital care. Earlier consultation could be beneficial to patients and reduce costs of care. Show less
Doets, A.Y.; Verboon, C.; Berg, B. van den; Harbo, T.; Cornblath, D.R.; Willison, H.J.; ... ; IGOS Consortium 2018
This article focuses on the role of government in relation to cybersecurity. Traditionally, cybersecurity was primarily seen as a technical issue. In recent years, governments have realised that... Show moreThis article focuses on the role of government in relation to cybersecurity. Traditionally, cybersecurity was primarily seen as a technical issue. In recent years, governments have realised that they, too, have a stake in securing the Internet. In their attempts to grapple with cybersecurity, governments often turn to technical solutions to ‘code away’ illegal or undesired behaviours. ‘Techno-regulation’ has become popular because it may seem to be an effective and cheap way of increasing control over end users’ behaviours and increasing cybersecurity. In this article, we will explain why using techno-regulation has significant downsides and, therefore, why it may be unwise to use it as a dominant regulatory strategy for securing the Internet. We argue that other regulatory strategies ought to be considered as well, most importantly: trust. The second part of this article explains that trust can be used as an implicit strategy to increase cybersecurity or as an explicit mechanism for the same goal. Show less
Malan, D.F.; Walt, S.J. van der; Raidou, R.G.; Berg, B. van den; Stoel, B.C.; Botha, C.P.; ... ; Valstar, E.R. 2016
