Rainer Dziewas

University of Münster, Muenster, North Rhine-Westphalia, Germany

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Publications (143)441.17 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Although early identification of patients at risk for dysphagia is crucial in acute stroke care, predicting whether a particular patient is likely to have swallowing problems based on the brain scan is difficult because a comprehensive model of swallowing control is missing. In this study whether stroke location is associated with dysphagia incidence, severity and the occurrence of penetration or aspiration was systematically evaluated relying on a voxel-based imaging analysis approach. Two hundred acute stroke patients were investigated applying fiberoptic endoscopic evaluation of swallowing within 96 h from admission. Lesion masks were obtained from each patient's brain scan and registered to standard space. The percentage of lesioned volume of 137 atlas-based brain regions was determined in each case. Region-specific odds ratios were afterwards calculated with respect to presence of dysphagia, its severity and occurrence of penetration or aspiration. In all, 165 patients were diagnosed with dysphagia, 80 of whom had severe swallow impairment. For each investigated item there were significant differences of regional percentage infarction in distinct brain areas between affected patients and those who did not present with that specific dysfunction. In particular, right hemispheric lesions of the pre- and post-central gyri, opercular region, supramarginal gyrus and respective subcortical white matter tracts were related to dysphagia, with post-central lesions being especially associated with severe swallowing impairment. Distinct brain lesion locations are related to the incidence, severity and pattern of swallowing dysfunction. © 2015 EAN.
    European Journal of Neurology 02/2015; · 3.85 Impact Factor
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    ABSTRACT: Modulation of cortical swallowing-associated activation by PES was assessed with MEG.•PES induced a right-dominant attenuation of ERD in alpha and beta frequency ranges.•Attenuation reflects stimulation-induced increased swallowing processing efficiency.•Neuroplastic changes are associated with behavioral gains.
    NeuroImage 01/2015; 104. · 6.13 Impact Factor
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    ABSTRACT: Eligibility criteria are a key factor for the feasibility and validity of clinical trials. We aimed to develop an online tool to assess the potential effect of inclusion and exclusion criteria on the proportion of patients eligible for an acute stroke trial.
    Stroke 11/2014; 46(1). · 6.02 Impact Factor
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    ABSTRACT: Abstract Purpose/Aim Cerebrovascular events (CVE) in HIV infected patients have become an increasingly relevant neurological complication. Data about the prevalence and clinical features of CVE in HIV infected patients since the introduction of combined Anti-Retroviral Therapy (cART) are rare. Methods A retrospective study of HIV-infected patients with a CVE was performed from 2002-2011. During this time period 3203 HIV-infected patients were admitted to the University hospital of Muenster, Germany. All patients had access to regular and long term treatment with cART. The clinical features were analyzed and the prevalence of ischemic stroke (IS), transient ischemic attack (TIA) and intracerebral bleeding (ICB) was calculated. Results The total prevalence of all CVE was at 0.6% (95% CI: 0.3, 0.8) (0.4% for IS (95% CI: 0.2, 0.6), 0.2% for TIA (95% CI: 0.0, 0.3) and 0.1% for ICB (95% CI: 0.0, 0.2)) and the crude annual incidence rate at 59 per 100.000 for all events. The median CD4 cell count was 405/μl (25(th) to 75(th) percentile: 251-568). The majority of patients had AIDS. The median age was at 49 years (25(th) to 75(th) percentile: 40-69). Some events were associated with HIV-associated vasculopathy or viral co-infections. Most patients presented with multiple vascular risk factors. Conclusion The study confirms that CVE occur in HIV-infected patients with a good immune status and at a young age. HIV infection has to be considered in young stroke patients. The rate of CVE in this study was constant when comparing to the pre-cART era. HIV associated vasculopathy and viral co-infections need to be considered in the diagnostics of stroke.
    International Journal of Neuroscience 08/2014; · 1.53 Impact Factor
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    ABSTRACT: Neurogenic dysphagia is one of the most frequent and prognostically relevant neurological deficits in a variety of disorders, such as stroke, parkinsonism and advanced neuromuscular diseases. Flexible endoscopic evaluation of swallowing (FEES) is now probably the most frequently used tool for objective dysphagia assessment in Germany. It allows evaluation of the efficacy and safety of swallowing, determination of appropriate feeding strategies and assessment of the efficacy of different swallowing manoeuvres. The literature furthermore indicates that FEES is a safe and well-tolerated procedure. In spite of the huge demand for qualified dysphagia diagnostics in neurology, a systematic FEES education has yet not been established. The structured training curriculum presented in this article aims to close this gap and intends to enforce a robust and qualified FEES service. As management of neurogenic dysphagia is not confined to neurologists, this educational program is applicable to other clinicians and speech language therapists with expertise in dysphagia as well.
    Der Nervenarzt 07/2014; · 0.86 Impact Factor
  • Parkinsonism & Related Disorders 06/2014; · 4.13 Impact Factor
  • Gastrointestinal Endoscopy 05/2014; 79(5):AB515. · 4.90 Impact Factor
  • Parkinsonism & Related Disorders 04/2014; 20(4). · 4.13 Impact Factor
  • Der Nervenarzt 04/2014; 85(4):482-4. · 0.86 Impact Factor
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    ABSTRACT: Current neuroimaging research on functional disturbances provides growing evidence for objective neuronal correlates of allegedly psychogenic symptoms, thereby shifting the disease concept from a psychological towards a neurobiological model. Functional dysphagia is such a rare condition, whose pathogenetic mechanism is largely unknown. In the absence of any organic reason for a patient's persistent swallowing complaints, sensorimotor processing abnormalities involving central neural pathways constitute a potential etiology. In this pilot study we measured cortical swallow-related activation in 5 patients diagnosed with functional dysphagia and a matched group of healthy subjects applying magnetoencephalography. Source localization of cortical activation was done with synthetic aperture magnetometry. To test for significant differences in cortical swallowing processing between groups, a non-parametric permutation test was afterwards performed on individual source localization maps. Swallowing task performance was comparable between groups. In relation to control subjects, in whom activation was symmetrically distributed in rostro-medial parts of the sensorimotor cortices of both hemispheres, patients showed prominent activation of the right insula, dorsolateral prefrontal cortex and lateral premotor, motor as well as inferolateral parietal cortex. Furthermore, activation was markedly reduced in the left medial primary sensory cortex as well as right medial sensorimotor cortex and adjacent supplementary motor area (p<0.01). Functional dysphagia - a condition with assumed normal brain function - seems to be associated with distinctive changes of the swallow-related cortical activation pattern. Alterations may reflect exaggerated activation of a widely distributed vigilance, self-monitoring and salience rating network that interferes with down-stream deglutition sensorimotor control.
    PLoS ONE 02/2014; 9(2):e89665. · 3.53 Impact Factor
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    ABSTRACT: Stroke is regularly accompanied by dysphagia and other factors associated with decreased nutritional intake. Dysphagia with aspiration pneumonia and insufficient nutritional intake lead to worse outcome after stroke.This guideline is the first chapter of the guideline "Clinical Nutrition in Neurology" of the German Society for Clinical Nutrition (DGEM) which itself is one part of a comprehensive guideline about all areas of Clinical Nutrition. The thirty-one recommendations of the guideline are based on a systematic literature search and review, last updated December 31, 2011. All recommendations were discussed and consented at several consensus conferences with the entire DGEM guideline group. The recommendations underline the importance of an early screening and assessment of dysphagia and give advice for an evidence based and comprehensive nutritional management to avoid aspiration, malnutrition and dehydration.
    Experimental and Translational Stroke Medicine 12/2013; 5(1):14.
    This article is viewable in ResearchGate's enriched format
  • Sonja Suntrup, Rainer Dziewas
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    ABSTRACT: Swallowing is an essential part of life, whose central neural processing has increasingly been explored over the last two decades. Besides the well-known significance of medullary structures, involvement of a bilateral, widely distributed cortical and subcortical network has been shown. Moreover, the role of distinct brain areas could be related to specific aspects of swallowing control. Stroke is the most frequent reason for swallowing dysfunction. Dysphagia in stroke has a reported incidence of approximately 50% and is associated with increased mortality due to aspiration pneumonia. While 15% of patients suffer from persistent dysphagia, the majority shows fast recovery of swallow function within days to weeks. Thus, stroke constitutes a convenient lesion model to evaluate functional recovery due to spontaneous neuronal plasticity and following therapeutic interventions. The remarkable recovery of stroke-related dysphagia depends on compensatory reorganization in the undamaged hemisphere. The focus of treatment studies is therefore shifting from exercise-based manipulation of swallowing biomechanics towards approaches that modulate the underlying neural systems. By influencing cortical excitability and activity levels these methods are said to promote structural and functional reorganization resulting in clinical improvement. Techniques include those applied to the cortex like transcranial magnetic or direct current stimulation, but also those applied to the periphery, such as pharyngeal electrical stimulation. Some of these techniques have reached a stage of development that makes future use in clinical practice conceivable. Increasing the effect size and duration by further optimizing stimulation protocols will be a crucial issue.
    Klinische Neurophysiologie 11/2013; 44(04):247-256. · 0.33 Impact Factor
  • Der Nervenarzt 08/2013; 84(8):1003. · 0.86 Impact Factor
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    ABSTRACT: : Decisions regarding tracheostomy tube removal after mechanical ventilation often depend on the physician's individual experience because evidence-based practice guidelines are still scarce, especially for critically ill neurologic patients. In these patients, the prevalence of aspiration is high and regarded as an important contributor to decannulation failure. The presence of severe neurological deficits may, however, give clinicians the subjective impression that a tracheostomy tube is still necessary although decannulation may actually be safe. It is therefore crucial to test swallowing function reliably prior to decannulation in this patient population. : Prospective observational study. : University hospital, neurological ICU. : One hundred tracheostomized patients with acute neurologic disease completely weaned from mechanical ventilation. : An endoscopic protocol evaluating readiness for decannulation and a conventional clinical swallowing examination were carried out by separate, experienced practitioners blinded to each other's decisions. Patient management always followed the decision made with endoscopy. : Practitioners' decannulation decisions (yes/no) reached with both assessments were compared. Decannulated patients were monitored throughout their stay for complications related to tube removal. Endoscopy was performed successfully in all subjects without any complications. Following the protocol, the tracheostomy tube was successfully removed in 54 patients, whereas according to the clinical swallowing examination, only 29 patients would have been decannulated at that point. Only one patient needed recannulation due to respiratory problems, resulting in a failure rate of 1.9%. : In neurologic patients, speech-language pathologists' impressions about the patient's state when clinically assessing indirect variables of swallowing function often lead to the unnecessary prolongation of cannulation time. Endoscopic evaluation has the advantage of objectively visualizing the patient's ability to manage secretions directly and allows for faster but, nonetheless, safe decannulation. The endoscopic protocol proposed here is a safe, efficient, and objective bedside tool to guide decannulation decisions.
    Critical care medicine 07/2013; 41(7):1728-32. · 6.15 Impact Factor
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    ABSTRACT: Swallowing is a complex neuromuscular task that is processed within multiple regions of the human brain. Rehabilitative treatment options for dysphagia due to neurological diseases are limited. Because the potential for adaptive cortical changes in compensation of disturbed swallowing is recognized, neuromodulation techniques like transcranial direct current stimulation (tDCS) are currently considered as a treatment option. Here we evaluate the effect of tDCS on cortical swallowing network activity and behavior. In a double-blind crossover study, anodal tDCS (20 min, 1 mA) or sham stimulation was administered over the left or right swallowing motor cortex in 21 healthy subjects in separate sessions. Cortical activation was measured using magnetoencephalography (MEG) before and after tDCS during cued "simple", "fast" and "challenged" swallow tasks with increasing levels of difficulty. Swallowing response times and accuracy were measured. Significant bilateral enhancement of cortical swallowing network activation was found in the theta frequency range after left tDCS in the fast swallow task (p = 0.006) and following right tDCS in the challenged swallow task (p = 0.007), but not after sham stimulation. No relevant behavioral effects were observed on swallow response time, but swallow precision improved after left tDCS (p < 0.05). Anodal tDCS applied over the swallowing motor cortex of either hemisphere was able to increase bilateral swallow-related cortical network activation in a frequency specific manner. These neuroplastic effects were associated with subtle behavioral gains during complex swallow tasks in healthy individuals suggesting that tDCS deserves further evaluation as a treatment tool for dysphagia.
    NeuroImage 06/2013; · 6.13 Impact Factor
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    ABSTRACT: Schluckstörungen finden sich bei ca. 50 % aller Patienten mit einem akuten Schlaganfall, begünstigen das Auftreten von Aspirationspneumonien und gehen mit einer erhöhten Morbidität und Mortalität einher. In Ergänzung zur klinischen Dysphagiediagnostik ermöglicht insbesondere die FEES (,,flexible endoscopic evaluation of swallowing“), dieses Störungsbild mit vertretbarem Aufwand und ohne relevante Gefährdung des Patienten rasch und präzise zu detektieren. In Anbetracht der zunehmenden Verwendung der FEES auf den deutschen Stroke-Units werden in dieser Arbeit Empfehlungen für ihre Etablierung und Durchführung formuliert.Die für die Durchführung der FEES erforderlichen Kenntnisse und Fertigkeiten sollten in einem dreistufigen Prozess erworben werden, der zu Beginn eine strukturierte Fortbildung, anschließend die Untersuchung unter Supervision und schließlich das selbständige Endoskopieren, idealerweise ergänzt durch regelmäßige Besprechungen ausgewählter Befunde, vorsieht. Die FEES sollte im Team von einem Arzt und einem Logopäden (alternativ einem klinischen Linguisten oder einem Sprachtherapeuten) durchgeführt werden. Die Aufgabenverteilung zwischen Arzt und Logopäden kann dabei unter Berücksichtigung des jeweiligen Ausbildungsstandes flexibel erfolgen, keinesfalls ist die Rolle des Logopäden auf reine Assistenztätigkeiten zu reduzieren. Die endoskopische Schweregradeinteilung der schlaganfallbedingten Dysphagie inklusive der zugeordneten therapeutischen Implikationen sollte nach einem in der jeweiligen Einrichtung fest etablierten, standardisierten Schema erfolgen, um so die interprofessionelle Kommunikation zu erleichtern und reibungslose und effiziente Abläufe zu garantieren. Eine zukünftig anzugehende, übergeordnete Aufgabe besteht darin, in Anlehnung an internationale Kriterien und unter Berücksichtigung der spezifischen Belange und Anforderungen deutscher Stroke-Units Ausbildungsstandards der FEES für Ärzte und Logopäden zu erarbeiten
    Der Nervenarzt 06/2013; · 0.86 Impact Factor
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    ABSTRACT: Dysphagia occurs in about 50 % of patients with acute stroke, is strongly related to early complications, such as aspiration pneumonia and is a major cause of increased morbidity and mortality in acute stroke. Flexible endoscopic evaluation of swallowing (FEES) has proven to be an easy to use, non-invasive tool for assessment of dysphagia in acute stroke, significantly adding accuracy to the clinical evaluation of dysphagia. With respect to the growing use of FEES in German stroke units this article summarizes recommendations for implementation and execution.A 3-step process is recommended to acquire the relevant knowledge and skills for carrying out FEES. After a systematic training (first step), swallowing endoscopy should be done under close supervision (second step) which is then followed by independent practice coupled with indirect supervision (third step). In principle, FEES should adopt a team approach involving both neurologists and speech language pathologists (SLP) or alternatively speech therapists. The allocation of responsibilities between these two professions should be kept flexible and should be adjusted to the individual level of education. Reducing the role of the SLP to mere assistance work in particular should be avoided. To enhance interprofessional communication and to allow for a smooth and efficient workflow, endoscopic grading of stroke-related dysphagia should adopt a standardized score that also includes protective and rehabilitative measures as well as nutritional recommendations. A major task for the future is to develop an educational curriculum for FEES that takes the specific needs of stroke unit care into account and is applicable to both physicians and SLPs.
    Der Nervenarzt 05/2013; · 0.86 Impact Factor
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    ABSTRACT: Background Optimal management of physiological parameters in neurological/neurosurgical intensive care units (NICUs) is largely unclear as high-quality evidence is lacking. The aim of this survey was to investigate if standards exist in the use of clinical scores, systemic and cerebral monitoring and the targeting of physiology values and in what way this affects clinical management in German NICUs. Methods National survey, on-line anonymized questionnaire. German departments stating to run a neurological, neurosurgical or interdisciplinary neurological/neurosurgical intensive care unit were identified by a web-based search of all German hospitals and contacted via email. Results Responses from 78 German NICUs were obtained. Of 19 proposed clinical/laboratory/radiological scores only 5 were used regularly by >60 %. Bedside neuromonitoring (NM) predominantly consisted of transcranial Doppler sonography (94 %), electroencephalography (92 %) and measurement of intracranial pressure (ICP) (90 %), and was installed if patients had or were threatened by elevated ICP (86 %), had specific diseases like subarachnoid hemorrhage (51 %) or were comatose (35 %). Although mean trigger values for interventions complied with guidelines or wide-spread customs, individual trigger values varied widely, e.g., for hyperglycemia (maximum blood glucose between 120 and 250 mg/dl) or for anemia (minimum hemoglobin values between 5 and 10 g/dl). Conclusions Although apparently aiming for standardization in neurocritical care, German NICUs show substantial differences in NM and monitoring-associated interventions. In terms of scoring and monitoring methods, German NICUs seem to be quite conservative. These survey results suggest a need of prospective and randomized interventional trials in neurocritical care to help define standards and target values.
    Neurocritical Care 04/2013; 20(2):176-186. · 2.60 Impact Factor
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    ABSTRACT: Dysphagia is a relevant symptom in Parkinson's disease, whose pathophysiology is poorly understood. It is mainly attributed to degeneration of brainstem nuclei. However, alterations in the cortical contribution to deglutition control in the course of Parkinson's disease have not been investigated. Here, we sought to determine the patterns of cortical swallowing processing in patients with Parkinson's disease with and without dysphagia. Swallowing function in patients was objectively assessed with fiberoptic endoscopic evaluation. Swallow-related cortical activation was measured using whole-head magnetoencephalography in 10 dysphagic and 10 non-dysphagic patients with Parkinson's disease and a healthy control group during self-paced swallowing. Data were analysed applying synthetic aperture magnetometry, and group analyses were done using a permutation test. Compared with healthy subjects, a strong decrease of cortical swallowing activation was found in all patients. It was most prominent in participants with manifest dysphagia. Non-dysphagic patients with Parkinson's disease showed a pronounced shift of peak activation towards lateral parts of the premotor, motor and inferolateral parietal cortex with reduced activation of the supplementary motor area. This pattern was not found in dysphagic patients with Parkinson's disease. We conclude that in Parkinson's disease, not only brainstem and basal ganglia circuits, but also cortical areas modulate swallowing function in a clinically relevant way. Our results point towards adaptive cerebral changes in swallowing to compensate for deficient motor pathways. Recruitment of better preserved parallel motor loops driven by sensory afferent input seems to maintain swallowing function until progressing neurodegeneration exceeds beyond the means of this adaptive strategy, resulting in manifestation of dysphagia.
    Brain 03/2013; 136(Pt 3):726-38. · 10.23 Impact Factor

Publication Stats

1k Citations
441.17 Total Impact Points

Institutions

  • 2001–2015
    • University of Münster
      • • Department of Neurology
      • • Institute of Biomagnetism and Biosignalanalysis
      Muenster, North Rhine-Westphalia, Germany
  • 2001–2014
    • Universitätsklinikum Münster
      • Klinik und Poliklinik für Neurologie
      Muenster, North Rhine-Westphalia, Germany
  • 2013
    • University Hospital Essen
      • Institute of Diagnostic and Interventional Radiology and Neuroradiology
      Essen, North Rhine-Westphalia, Germany
  • 2012
    • Universität Heidelberg
      • Clinik of Neurology
      Heidelberg, Baden-Wuerttemberg, Germany
    • Paracelsus Medical University Salzburg
      Salzburg, Salzburg, Austria
  • 2003–2004
    • University of Toronto
      Toronto, Ontario, Canada