Timo Siepmann

Prof. Dr. Timo Siepmann

Department of NeurologyUniversity Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 June 2016 in Neuropsychiatric Disease and Treatment
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Journal Article
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Timo SiepmannTimo Siepmann
Timo Siepmann
PSPeter Markus Spieth
Peter Markus Spieth
AKAnne Sophie Kubasch
Anne Sophie Kubasch
APAna Isabel Penzlin
Ana Isabel Penzlin
BIBen Min-Woo Illigens
Ben Min-Woo Illigens
KBKristian Barlinn
Kristian Barlinn
Randomized controlled trials (RCTs) are the hallmark of evidence-based medicine and form the basis for translating research data into clinical practice. This review summarizes commonly applied designs and quality indicators of RCTs to provide guidance in interpreting and critically evaluating clinical research data. It further reflects on the principle of equipoise and its practical applicability to clinical science with an emphasis on critical care and neurological research. We performed a review of educational material, review articles, methodological studies, and published clinical trials using the databases MEDLINE, PubMed, and ClinicalTrials.gov. The most relevant recommendations regarding design, conduction, and reporting of RCTs may include the following: 1) clinically relevant end points should be defined a priori, and an unbiased analysis and report of the study results should be warranted, 2) both significant and nonsignificant results should be objectively reported and published, 3) structured study design and performance as indicated in the Consolidated Standards of Reporting Trials statement should be employed as well as registration in a public trial database, 4) potential conflicts of interest and funding sources should be disclaimed in study report or publication, and 5) in the comparison of experimental treatment with standard care, preplanned interim analyses during an ongoing RCT can aid in maintaining clinical equipoise by assessing benefit, harm, or futility, thus allowing decision on continuation or termination of the trial.

10 August 2017 in BMC Cancer
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Journal Article
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MHMarkus V Heppt
Markus V Heppt
Timo SiepmannTimo Siepmann
Timo Siepmann
JEJutta Engel
Jutta Engel
GSGabriele Schubert-Fritschle
Gabriele Schubert-Fritschle
RERenate Eckel
Renate Eckel
CBCarola Berking
Carola Berking
Hotspot mutations of the oncogenes BRAF and NRAS are the most common genetic alterations in cutaneous melanoma. Specific inhibitors of BRAF and MEK have shown significant survival benefits in large phase III trials. However, the prognostic significance of BRAF and NRAS mutations outside of clinical trials remains unclear. The mutational status of BRAF (exon 15) and NRAS (exon 2 and 3) was determined in melanoma samples of 217 patients with pyrosequencing and Sanger sequencing. The genotypes were correlated with clinical outcomes and pathologic features of the primary tumors. Time to disease progression was calculated with the cumulative incidence function. Survival analyses were performed with Kaplan-Meier estimates and Cox proportional hazards regression analysis. Relative survival was calculated with the Ederer-II method. Treatment with BRAF and MEK inhibitors and immune checkpoint blockade (ICB) was allowed. Mutations in BRAF and NRAS were identified in 40.1 and 24.4% of cases, respectively. Concurrent mutations in both genes were detected in further 2.3%. The remaining 33.2% were wild type for the investigated exons (WT). BRAF mutations were significantly associated with younger age at first diagnosis (p < 0.001) and truncal localization of the culprit primary (p = 0.002). The nodular subtype was most common in the NRAS cohort. In addition, NRAS-mutant melanoma patients showed a higher frequency of nodal relapse (p = 0.013) and development of metastatic disease (p = 0.021). The time to loco-regional nodal relapse was shortest in NRAS-mutant melanoma (p = 0.002). Presence of NRAS mutation was an independent risk factor for disease progression in multivariate analysis (HR 2.01; 95% CI 1.02 – 3.98). BRAF-mutant melanoma patients showed a tendency for better overall and relative survival. Genotype was not a consistent risk factor in multivariate analysis. Instead, positive sentinel lymph node status (HR 2.65; 95% CI 1.15 – 6.10) and treatment with ICB in stage IV disease (HR 0.17; 95% CI 0.06–0.48) were significant multivariate risk factors. NRAS-mutant tumors tended to behave more aggressively particularly in early stages of the disease in this high-risk melanoma population. Treatment with immune checkpoint blockade improved survival in stage IV disease in a real-world setting.

8 June 2021 in Neurology
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RNRaul G. Nogueira
Raul G. Nogueira
MQMuhammad M. Qureshi
Muhammad M. Qureshi
MAMohamad Abdalkader
Mohamad Abdalkader
SMSheila Ouriques Martins
Sheila Ouriques Martins
HYHiroshi Yamagami
Hiroshi Yamagami
ORon behalf of the SVIN COVID-19 Global Stroke Registry
on behalf of the SVIN COVID-19 Global Stroke Registry
Objective To measure the global impact of COVID-19 pandemic on volumes of IV thrombolysis (IVT), IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1 to June 30, 2020) compared with 2 control 4-month periods. Methods We conducted a cross-sectional, observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases. Results There were 91,373 stroke admissions in the 4 months immediately before compared to 80,894 admissions during the pandemic months, representing an 11.5% (95% confidence interval [CI] −11.7 to −11.3, p < 0.0001) decline. There were 13,334 IVT therapies in the 4 months preceding compared to 11,570 procedures during the pandemic, representing a 13.2% (95% CI −13.8 to −12.7, p < 0.0001) drop. Interfacility IVT transfers decreased from 1,337 to 1,178, or an 11.9% decrease (95% CI −13.7 to −10.3, p = 0.001). Recovery of stroke hospitalization volume (9.5%, 95% CI 9.2–9.8, p < 0.0001) was noted over the 2 later (May, June) vs the 2 earlier (March, April) pandemic months. There was a 1.48% stroke rate across 119,967 COVID-19 hospitalizations. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was noted in 3.3% (1,722/52,026) of all stroke admissions. Conclusions The COVID-19 pandemic was associated with a global decline in the volume of stroke hospitalizations, IVT, and interfacility IVT transfers. Primary stroke centers and centers with higher COVID-19 inpatient volumes experienced steeper declines. Recovery of stroke hospitalization was noted in the later pandemic months.

14 July 2017 in Frontiers in Neurology
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Journal Article
Open access
CRCarina Riediger
Carina Riediger
TSTibor Schuster
Tibor Schuster
KBKristian Barlinn
Kristian Barlinn
SMSarah Maier
Sarah Maier
JWJürgen Weitz
Jürgen Weitz
Timo SiepmannTimo Siepmann
Timo Siepmann
Background: Antidepressants are widely used in the treatment of chronic pain. Applied doses are lower than those needed to unfold an antidepressive effect. While efficacy of antidepressants for chronic pain has been reported in large randomized controlled trials, there is inconsistent data on adverse effects and tolerability. We aimed at synthesizing data from randomized controlled trials to explore adverse effect profiles and tolerability of antidepressants for treatment of chronic pain. Methods: Systematic literature research and meta-analyses were performed regarding side effects and safety of different antidepressants in the treatment of chronic pain according to PRISMA guidelines. The National Center for Biotechnology Information library and MEDLINE were searched. Randomized placebo-controlled trials were included in quantitative data synthesis. Results: Out of 1975 screened articles, 33 papers published between 1995 and 2015 were included in our review and 23 studies were included in the meta-analyses. A higher risk for adverse effects compared to placebo was observed in all antidepressants included in our analyses, except nortriptyline. The most prevalent adverse effects were dry mouth, dizziness, nausea, headache and constipation. Amitriptyline, mirtazapine, desipramine, venlafaxine, fluoxetine and nortriptyline showed the highest placebo effect-adjusted risk of adverse effects. Risk for withdrawal due to adverse effects was highest in desipramine (risk ratio: 4.09, 95%-CI [1.31; 12.82]) followed by milnacipran, venlafaxine and duloxetine. The most common adverse effects under treatment with antidepressants were dry mouth, dizziness, nausea, headache and constipation followed by palpitations, sweating and drowsiness. However, overall tolerability was high. Each antidepressant showed distinct risk profiles of adverse effects. Conclusion: Our synthesized data analysis confirmed overall tolerability of low dose antidepressants for the treatment of chronic pain and revealed drug specific risk profiles. This encompassing characterization of adverse effect profiles might be useful in defining multimodal treatment regimens for chronic pain which also consider patients’ comorbidities and co-medication.

12 April 2019 in Frontiers in Neurology
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JMJosé Javier Mendoza-Velásquez
José Javier Mendoza-Velásquez
JFJuan Francisco Flores-Vázquez
Juan Francisco Flores-Vázquez
EBEvalinda Barrón-Velázquez
Evalinda Barrón-Velázquez
ASAna Luisa Sosa-Ortiz
Ana Luisa Sosa-Ortiz
BIBen-Min Woo Illigens
Ben-Min Woo Illigens
Timo SiepmannTimo Siepmann
Timo Siepmann
The α-synucleinopathies are a group of neurodegenerative diseases characterized by abnormal accumulation of insoluble α-synuclein in neurons and glial cells, comprising Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Although varying in prevalence, symptom patterns, and severity among disorders, all α-synucleinopathies have in common autonomic nervous system dysfunctions, which reduce quality of life. Frequent symptoms among α-synucleinopathies include constipation, urinary and sexual dysfunction, and cardiovascular autonomic symptoms such as orthostatic hypotension, supine hypertension, and reduced heart rate variability. Symptoms due to autonomic dysfunction can appear before motor symptom onset, particularly in MSA and PD, hence, detection and quantitative analysis of these symptoms can enable early diagnosis and initiation of treatment, as well as identification of at-risk populations. While patients with PD, DLB, and MSA show both central and peripheral nervous system involvement of α-synuclein pathology, pure autonomic failure (PAF) is a condition characterized by generalized dysregulation of the autonomic nervous system with neuronal cytoplasmic α-synuclein inclusions in the peripheral autonomic small nerve fibers. Patients with PAF often present with orthostatic hypotension, reduced heart rate variability, anhydrosis, erectile dysfunction, and constipation, without motor or cognitive impairment. These patients also have an increased risk of developing an α-synucleinopathy with central involvement, such as PD, DLB, or MSA in later life, possibly indicating a pathophysiological disease continuum. Pathophysiological aspects, as well as developments in diagnosing and treating dysautonomic symptoms in patients with α-synucleinopathies are discussed in this review.

28 March 2017 in Neurology
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Journal Article
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Timo SiepmannTimo Siepmann
Timo Siepmann
HBHenry Boardman
Henry Boardman
ABAmy Bilderbeck
Amy Bilderbeck
LGLudovica Griffanti
Ludovica Griffanti
YKYvonne Kenworthy
Yvonne Kenworthy
PLPaul Leeson
Paul Leeson
Objective: To determine whether changes in cerebral structure are present after preeclampsia that may explain increased cerebrovascular risk in these women. Methods: We conducted a case control study in women between 5 and 15 years after either a preeclamptic or normotensive pregnancy. Brain MRI was performed. Analysis of white matter structure was undertaken using voxel-based segmentation of fluid-attenuation inversion recovery sequences to assess white matter lesion volume and diffusion tensor imaging to measure microstructural integrity. Voxel-based analysis of gray matter volumes was performed with adjustment for skull size. Results: Thirty-four previously preeclamptic women (aged 42.8 ± 5.1 years) and 49 controls were included. Previously preeclamptic women had reduced cortical gray matter volume (523.2 ± 30.1 vs 544.4 ± 44.7 mL, p < 0.05) and, although both groups displayed white matter lesions, changes were more extensive in previously preeclamptic women. They displayed increased temporal lobe white matter disease (lesion volume: 23.2 ± 24.9 vs 10.9 ± 15.0 μL, p < 0.05) and altered microstructural integrity (radial diffusivity: 538 ± 19 vs 526 ± 18 × 10−6 mm2/s, p < 0.01), which also extended to occipital and parietal lobes. The degree of temporal lobe white matter change in previously preeclamptic women was independent of their current cardiovascular risk profile (p < 0.05) and increased with time from index pregnancy (p < 0.05). Conclusion: A history of preeclampsia is associated with temporal lobe white matter changes and reduced cortical volume in young women, which is out of proportion to their classic cardiovascular risk profile. The severity of changes is proportional to time since pregnancy, which would be consistent with continued accumulation of damage after pregnancy.