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Astner-Rohracher A, Zimmermann G, Avigdor T, Abdallah C, Barot N, Brázdil M, Doležalová I, Gotman J, Hall JA, Ikeda K, Kahane P, Kalss G, Kokkinos V, Leitinger M, Mindruta I, Minotti L, Mizera MM, Oane I, Richardson M, Schuele SU, Trinka E, Urban A, Whatley B, Dubeau F, Frauscher B. Development and Validation of the 5-SENSE Score to Predict Focality of the Seizure-Onset Zone as Assessed by Stereoelectroencephalography. JAMA Neurol 2021; 79:70-79. [PMID: 34870697 PMCID: PMC8649918 DOI: 10.1001/jamaneurol.2021.4405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Importance Stereoelectroencephalography (SEEG) has become the criterion standard in case of inconclusive noninvasive presurgical epilepsy workup. However, up to 40% of patients are subsequently not offered surgery because the seizure-onset zone is less focal than expected or cannot be identified. Objective To predict focality of the seizure-onset zone in SEEG, the 5-point 5-SENSE score was developed and validated. Design, Setting, and Participants This was a monocentric cohort study for score development followed by multicenter validation with patient selection intervals between February 2002 to October 2018 and May 2002 to December 2019. The minimum follow-up period was 1 year. Patients with drug-resistant epilepsy undergoing SEEG at the Montreal Neurological Institute were analyzed to identify a focal seizure-onset zone. Selection criteria were 2 or more seizures in electroencephalography and availability of complete neuropsychological and neuroimaging data sets. For validation, patients from 9 epilepsy centers meeting these criteria were included. Analysis took place between May and July 2021. Main Outcomes and Measures Based on SEEG, patients were grouped as focal and nonfocal seizure-onset zone. Demographic, clinical, electroencephalography, neuroimaging, and neuropsychology data were analyzed, and a multiple logistic regression model for developing a score to predict SEEG focality was created and validated in an independent sample. Results A total of 128 patients (57 women [44.5%]; median [range] age, 31 [13-58] years) were analyzed for score development and 207 patients (97 women [46.9%]; median [range] age, 32 [16-70] years) were analyzed for validation. The score comprised the following 5 predictive variables: focal lesion on structural magnetic resonance imaging, absence of bilateral independent spikes in scalp electroencephalography, localizing neuropsychological deficit, strongly localizing semiology, and regional ictal scalp electroencephalography onset. The 5-SENSE score had an optimal mean (SD) probability cutoff for identifying a focal seizure-onset zone of 37.6 (3.5). Area under the curve, specificity, and sensitivity were 0.83, 76.3% (95% CI, 66.7-85.8), and 83.3% (95% CI, 72.30-94.1), respectively. Validation showed 76.0% (95% CI, 67.5-84.0) specificity and 52.3% (95% CI, 43.0-61.5) sensitivity. Conclusions and Relevance High specificity in score development and validation confirms that the 5-SENSE score predicts patients where SEEG is unlikely to identify a focal seizure-onset zone. It is a simple and useful tool for assisting clinicians to reduce unnecessary invasive diagnostic burden on patients and overutilization of limited health care resources.
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Venard G, Pina Brito V, Eeckhout P, Zimmermann G, Van Petegem S. Quand le parent veut trop bien faire : état de la littérature sur le phénomène de surprotection parentale. PSYCHOLOGIE FRANCAISE 2021. [DOI: 10.1016/j.psfr.2021.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Egger-Rainer A, Hettegger SM, Feldner R, Arnold S, Bosselmann C, Hamer H, Hengsberger A, Lang J, Lorenzl S, Lerche H, Noachtar S, Pataraia E, Schulze-Bonhage A, Staack AM, Trinka E, Unterberger I, Zimmermann G. Do all patients in the epilepsy monitoring unit experience the same level of comfort? A quantitative exploratory secondary analysis. J Adv Nurs 2021; 78:2004-2014. [PMID: 34837405 PMCID: PMC9299695 DOI: 10.1111/jan.15105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 09/22/2021] [Accepted: 11/04/2021] [Indexed: 11/28/2022]
Abstract
Aims To find out which variables may be associated with comfort of patients in an epilepsy monitoring unit. Design Exploratory, quantitative study design. Methods Data were collected from October 2018 to November 2019 in Austria and Southern Germany. A total of 267 patients of 10 epilepsy centres completed the Epilepsy Monitoring Unit Comfort Questionnaire which is based on Kolcaba's General Comfort Questionnaire. Secondary data analysis were conducted by using descriptive statistics and an exploratory model building approach, including different linear regression models and several sensitivity analyses. Results Total comfort scores ranged from 83 to 235 points. Gender, occupation and centre turned out to be possible influential variables. On average, women had a total comfort score 4.69 points higher than men, and retired persons 28.2 points higher than high school students ≥18 years. Comfort scores of younger patients were lower than those of older patients. However, age did not show a statistically significant effect. The same could be observed in marital status and educational levels. Conclusion When implementing comfort measures, nurses must be aware of variables which could influence the intervention negatively. Especially, high school students ≥18 years should be supported by epilepsy specialist nurses, in order to reduce uncertainty, anxiety and discomfort. But, since the identified variables account only for a small proportion of the inter‐individual variability in comfort scores, further studies are needed to find out additional relevant aspects and to examine centre‐specific effects more closely. Impact Nurses ensure patient comfort during a hospital stay. However, there are variables that may impair the effectiveness of the nursing measures. Our study showed that the experience of comfort was highly individual and could be explained by sociodemographic variables only to a limited extent. Nurses must be aware that additional factors, such as the situation in the individual setting, may be relevant.
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Aleksovska K, Kobulashvili T, Costa J, Zimmermann G, Ritchie K, Reinhard C, Vignatelli L, Fanciulli A, Damian M, Pavlakova L, Burgunder JM, Rakusa M, Kovacs N, Erdogan F, Linton L, Copetti M, Lamperti C, Servidei S, Evangelista T, Ayme S, Pareyson D, Sellner J, Kopishinskaya S, Krarup C, De Visser M, Van Den Bergh P, Toscano A, Graessner H, Berger T, Bassetti C, Vidailhet M, Trinka E, Deuschl G, Federico A, Leone M. EAN guidance for developing and reporting clinical practice guidelines on rare neurological diseases. J Neurol Sci 2021. [DOI: 10.1016/j.jns.2021.119938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Konietschke F, Cao C, Gunawardana A, Zimmermann G. Analysis of covariance under variance heteroscedasticity in general factorial designs. Stat Med 2021; 40:4732-4749. [PMID: 34128244 DOI: 10.1002/sim.9092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 11/06/2022]
Abstract
Adjusting for baseline values and covariates is a recurrent statistical problem in medical science. In particular, variance heteroscedasticity is non-negligible in experimental designs and ignoring it might result in false conclusions. Approximate inference methods are developed to test null hypotheses formulated in terms of adjusted treatment effects and regression parameters in general analysis of covariance designs with arbitrary numbers of factors. Variance homoscedasticity is not assumed. The distributions of the test statistics are approximated using Box-type approximation methods. Extensive simulation studies show that the procedures are particularly suitable when sample sizes are rather small. A real data set illustrates the application of the methods.
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Weichselbaum N, Oberladstätter D, Schlimp CJ, Zipperle J, Voelckel W, Grottke O, Zimmermann G, Osuchowski M, Schöchl H. High Interleukin-6 Plasma Concentration upon Admission Is Predictive of Massive Transfusion in Severely Injured Patients. J Clin Med 2021; 10:jcm10112268. [PMID: 34073768 PMCID: PMC8197216 DOI: 10.3390/jcm10112268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/11/2021] [Accepted: 05/18/2021] [Indexed: 11/30/2022] Open
Abstract
Severe bleeding remains a prominent cause of early in-hospital mortality in major trauma patients. Thus, prompt prediction of patients at risk of massive transfusion (MT) is crucial. We investigated the ability of the inflammatory marker interleukin (IL)-6 to forecast MT in severely injured trauma patients. IL-6 plasma levels were measured upon admission. Receiver operating characteristic curves (ROCs) were calculated, and sensitivity and specificity were determined. In this retrospective study, a total of 468 predominantly male (77.8%) patients, with a median injury severity score (ISS) of 25 (17–34), were included. The Youden index for the prediction of MT within 6 and 24 h was 351 pg/mL. Patients were dichotomized into two groups: (i) low-IL-6 < 350 pg/mL and (ii) high-IL-6 ≥ 350 pg/mL. IL-6 ≥ 350 pg/mL was associated with a lower prothrombin time index, a higher activated partial thromboplastin time, and a lower fibrinogen concentration compared with IL-6 < 350 pg/mL (p <0.0001 for all). Thromboelastometric parameters were significantly different between groups (p <0.03 in all). More patients in the high-IL-6 group received MT (p <0.0001). The ROCs revealed an area under the curve of 0.76 vs. 0.82 for the high-IL-6 group for receiving MT in the first 6 and 24 h. IL-6 ≥ 350 pg/mL predicted MT within 6 and 24 h with a sensitivity of 45% and 58%, respectively, and a specificity of 89%. IL-6 ≥ 350 pg/mL appears to be a reasonable early predictor for coagulopathy and MT within the first 6 and 24 h intervals. Large-scale prospective studies are warranted to confirm these findings.
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Pilz J, Hehenwarter L, Zimmermann G, Rendl G, Schweighofer-Zwink G, Beheshti M, Pirich C. Feasibility of equivalent performance of 3D TOF [ 18F]-FDG PET/CT with reduced acquisition time using clinical and semiquantitative parameters. EJNMMI Res 2021; 11:44. [PMID: 33934218 PMCID: PMC8088415 DOI: 10.1186/s13550-021-00784-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/23/2021] [Indexed: 11/24/2022] Open
Abstract
Background High-performance time-of-flight (TOF) positron emission tomography (PET) systems have the capability for rapid data acquisition while preserving diagnostic image quality. However, determining a reliable and clinically applicable cut-off of the acquisition time plays an important role in routine practice. This study aimed to assess the diagnostic equivalence of short acquisition time of 57 with routine 75 seconds per bed position (s/BP) of [18F]-fluoro-deoxy-glucose (FDG) PET. Phantom studies applying EARL criteria suggested the feasibility of shortened acquisition time in routine clinical imaging by 3D TOF PET/CT scanners. Ninety-six patients with melanoma, lung or head and neck cancer underwent a standard whole-body, skull base-to-thigh or vertex-to-thigh [18F]-FDG PET/CT examination using the 3D TOF Ingenuity TF PET/CT system (Philips, Cleveland, OH). The [18F]-FDG activity applied was equal to 4MBq per kg body weight. Retrospectively, PET list-mode data were used to calculate a second PET study per patient with a reduced acquisition time of 57 s instead of routine 75 s/BP. PET/CT data were reconstructed using a 3D OSEM TOF algorithm. Blinded patient data were analysed by two nuclear medicine physicians. The number of [18F]-FDG-avid lesions per body region (head&neck, thorax, abdomen, bone, extremity) and image quality (grade 1–5) were evaluated. Semiquantitative analyses were performed by standardized uptake value (SUV) measurements using 3D volume of interests (VOI). The visual and semiquantitative diagnostic equivalence of 214 [18F]-FDG-avid lesions were analysed in the routine standard (75 s/BP) as well as the calculated PET/CT studies with short acquisition time. Statistical analyses were performed by equivalence testing and Bland–Altman plots. Results Lesion detection rate per patient’s body region agreed in > 98% comparing 57 s/BP and 75 s/BP datasets. Overall image quality was determined as equal or superior to 75 s in 80% and 69%, respectively. In the semiquantitative lesion-based analyses, a significant equivalence was found between the 75 s/BP and 57 s/BP PET/CT images both for SUVmax (p = 0.004) and SUVmean (p = 0.003). Conclusion The results of this study demonstrate significant clinical and semiquantitative equivalence between short acquisition time of 57 s/BP and standard 75 s/BP 3D TOF [18F]-FDG PET/CT scanning, which may improve the patient’s workflow in routine practice.
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Kiesslich T, Beyreis M, Zimmermann G, Traweger A. Citation inequality and the Journal Impact Factor: median, mean, (does it) matter? Scientometrics 2020. [DOI: 10.1007/s11192-020-03812-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AbstractSkewed citation distribution is a major limitation of the Journal Impact Factor (JIF) representing an outlier-sensitive mean citation value per journal The present study focuses primarily on this phenomenon in the medical literature by investigating a total of n = 982 journals from two medical categories of the Journal Citation Report (JCR). In addition, the three highest-ranking journals from each JCR category were included in order to extend the analyses to non-medical journals. For the journals in these cohorts, the citation data (2018) of articles published in 2016 and 2017 classified as citable items (CI) were analysed using various descriptive approaches including e.g. the skewness, the Gini coefficient, and, the percentage of CI contributing 50% or 90% of the journal’s citations. All of these measures clearly indicated an unequal, skewed distribution with highly-cited articles as outliers. The %CI contributing 50% or 90% of the journal’s citations was in agreement with previously published studies with median values of 13–18% CI or 44–60% CI generating 50 or 90% of the journal’s citations, respectively. Replacing the mean citation values (corresponding to the JIF) with the median to represent the central tendency of the citation distributions resulted in markedly lower numerical values ranging from − 30 to − 50%. Up to 39% of journals showed a median citation number of zero in one medical journal category. For the two medical cohorts, median-based journal ranking was similar to mean-based ranking although the number of possible rank positions was reduced to 13. Correlation of mean citations with the measures of citation inequality indicated that the unequal distribution of citations per journal is more prominent and, thus, relevant for journals with lower citation rates. By using various indicators in parallel and the hitherto probably largest journal sample, the present study provides comprehensive up-to-date results on the prevalence, extent and consequences of citation inequality across medical and all-category journals listed in the JCR.
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Leitinger M, Poppert KN, Mauritz M, Rossini F, Zimmermann G, Rohracher A, Kalss G, Kuchukhidze G, Höfler J, Bosque Varela P, Kreidenhuber R, Volna K, Neuray C, Kobulashvili T, Granbichler CA, Siebert U, Trinka E. Status epilepticus admissions during the COVID-19 pandemic in Salzburg-A population-based study. Epilepsia 2020; 61:e198-e203. [PMID: 33140437 PMCID: PMC7756208 DOI: 10.1111/epi.16737] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/30/2020] [Accepted: 09/30/2020] [Indexed: 12/15/2022]
Abstract
Several emergencies were admitted less frequently to the hospital during the coronavirus disease 2019 (COVID‐19) pandemic. To investigate whether this also occurred with status epilepticus (SE) we compared admissions due to first SE from March to April 2020 (“Time of COVID,” TOC) with January to February 2020 (“pre‐COVID,” preCOV). We also compared admission numbers in TOC and preCOV with the respective 2‐month periods in 2018 and 2019 in a retrospective cohort analysis. Two investigators independently searched the hospital patient database for various forms of SE. There was no significant change in the 2‐month incidences of first SE in the city of Salzburg from preCOV of 6.1 (95% confidence interval [CI] 2.9‐12.3) to TOC of 6.9/100 000 adults (95% CI 3.4‐13.3). Admission numbers did not differ significantly from previous years. Estimated adjusted incidence was in line with a recent 5‐year epidemiological study in Salzburg. However, a trend toward less‐frequent nonconvulsive SE (NCSE) and loss of female predominance were indirect hints of underdiagnosing SE. In contrast to other medical conditions, SE most often presents clinically with impaired consciousness, which may promote admission to emergency departments even in times of lock‐down. Further research of medical support of women and patients with NCSE during pandemic‐related restrictions is warranted.
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Zimmermann G, Trinka E. Accounting for individual variability in baseline seizure frequencies when planning randomized clinical trials remains challenging. Epilepsia 2020; 61:2321-2322. [PMID: 32996125 DOI: 10.1111/epi.16676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 08/04/2020] [Indexed: 11/27/2022]
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Leitinger M, Trinka E, Zimmermann G, Granbichler CA, Kobulashvili T, Siebert U. Epidemiology of status epilepticus in adults: Apples, pears, and oranges - A critical review. Epilepsy Behav 2020; 103:106720. [PMID: 31902646 DOI: 10.1016/j.yebeh.2019.106720] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 11/02/2019] [Accepted: 11/13/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Status epilepticus (SE) is a severe neurologic condition associated with high morbidity and mortality. Population-based studies in adults have found a wide range of incidences in various regions in the world. Although the incidence of SE increases almost exponentially in the elderly, data on census-based population statistics in these studies are scarce. This study provides a critical review with an emphasis on census-based population statistics and study characteristics in adults. METHODS We performed a systematic search of population-based studies on SE in adults in PubMed using "status epilepticus" in combination with "epidemiology", "population", and "incidence" as search terms, and also screened references. For each identified study, we assessed and extracted the respective population pyramids of study and reference population, and study characteristics. RESULTS We identified 22 population-based studies (eleven from Europe, six from North America, three from Asia, one from Africa, and one from Australasia). Incidence rates of patients with SE ranged from 1.29 to 73.7/100,000 adults (95% confidence interval (CI): 76.6-80.3) and of SE episodes up to 81.1/100,000 adults (95% CI: 75.8-87.0). The proportions of elderly and very old patients varied by a factor of 2.6 and 8.5, respectively, depending on study period and place. Further major reasons for heterogeneity were retrospective or prospective study design, definition of time to diagnose SE, variable detection of nonconvulsive SE (NCSE), different etiologies, inclusion of children, recurrent episodes, postanoxic patients, exclusion of patients with preexisting epilepsy or patients identified outside the emergency department, and choice of reference population for age- and gender adjustment. The most recent definition and classification of SE by the International League Against Epilepsy (ILAE) 2015 was used in two studies. Four studies (18.2%) reported incidences per ten-year age strata necessary for age adjustment to various reference populations. CONCLUSIONS This critical review reveals a marked heterogeneity among population-based studies on SE in adults. It provides comprehensive details on census-based population statistics in study and reference populations and various study designs and characteristics essential for direct comparisons between studies. Reporting on these essential key features should be improved in population-based studies on SE.
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Happ M, Zimmermann G, Brunner E, Bathke AC. Pseudo-Ranks: How to Calculate Them Efficiently in R. J Stat Softw 2020. [DOI: 10.18637/jss.v095.c01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Leitinger M, Trinka E, Zimmermann G, Beniczky S. Salzburg criteria for nonconvulsive status epilepticus: Details matter. Epilepsia 2019; 60:2334-2336. [PMID: 31595496 PMCID: PMC6972514 DOI: 10.1111/epi.16361] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 08/23/2019] [Indexed: 12/04/2022]
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Grassner L, Wutte C, Zimmermann G, Grillhösl A, Schmid K, Weiβ T, Maier W, Hauck S, Hollerith T, Vogel M, Bierschneider M, Vastmans J, Thomé C, Gonschorek O, Strowitzki M. Influence of Preoperative Magnetic Resonance Imaging on Surgical Decision Making for Patients with Acute Traumatic Cervical Spinal Cord Injury: A Survey Among Experienced Spine Surgeons. World Neurosurg 2019; 131:e586-e592. [PMID: 31404692 DOI: 10.1016/j.wneu.2019.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Early decompression after acute spinal cord injury (SCI) is recommended. Acute care is crucial, but optimal management is unclear. The aim of this study was to investigate the role of preoperative magnetic resonance imaging (MRI) in addition to computed tomography (CT) in surgical decision making for acute cervical SCI. METHODS All patients with cervical SCI between 2008 and 2016 who had preoperative CT and MRI (n = 63) at the Trauma Center Murnau, Germany, were included. We administered a survey to 10 experienced spine surgeons (5 neurosurgeons, 5 trauma surgeons) regarding the surgical management. First, the surgeons were shown clinical information and CT scans. Two months later, the survey was repeated with additional MRI. Corresponding percentages of change and agreement were obtained for each rater and survey item. Finally, results from both parts of the survey were compared with the definitive treatment option (i.e., real-world decision). RESULTS MRI modified surgical timing in a median of 41% of patients (interquartile range 38%-56%). In almost every fifth patient (17%), no surgery would have been indicated with CT alone. The advocated surgical approach was changed in almost half of patients (median 48%, interquartile range 33%-49%). Surgically addressed levels were changed in a median of 57% of patients (interquartile range 56%-60%). MRI led to higher agreement with the real-world decision concerning addressed levels (median 35% vs. 73%), timing (median 51% vs. 57%), and approach (median 44% vs. 65%). CONCLUSIONS Preoperative MRI influenced surgical decision making substantially in our cohort and has become a new standard for patients with cervical SCI in our institution if medically possible.
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Zimmermann G, Bolter L, Sluka R, Höller Y, Bathke AC, Thomschewski A, Leis S, Lattanzi S, Brigo F, Trinka E. Sample sizes and statistical methods in interventional studies on individuals with spinal cord injury: A systematic review. J Evid Based Med 2019; 12:200-208. [PMID: 31231977 PMCID: PMC6771853 DOI: 10.1111/jebm.12356] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 05/12/2019] [Indexed: 12/13/2022]
Abstract
AIM Prevalence and incidence of spinal cord injury (SCI) are low. However, sample sizes have not been systematically examined yet, although this might represent useful information for study planning and power considerations. Therefore, our objective was to determine the median sample size in clinical trials on SCI individuals. Moreover, within small-sample size studies, statistical methods and awareness of potential problems regarding small samples were examined. METHODS We systematically reviewed all studies on human SCI individuals published between 2014 and 2015, where the effect of an intervention on one or more health-related outcomes was assessed by means of a hypothesis test. If at least one group had a size <20, the study was classified as a small sample size study. PubMed was searched for eligible studies; subsequently, data on sample sizes and statistical methods were extracted and summarized descriptively. RESULTS Out of 8897 studies 207 were included. Median total sample size was 18 (range 4-582). Small sample sizes were found in 167/207 (81%) studies, resulting limitations and implications for statistical analyses were mentioned in 109/167 (65%) studies. CONCLUSIONS Although most recent SCI trials have been conducted with small samples, the consequences on statistical analysis methods and the validity of the results are rarely acknowledged.
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Zimmermann G, Kieser M, Bathke AC. Sample size calculation and blinded recalculation for analysis of covariance models with multiple random covariates. J Biopharm Stat 2019; 30:143-159. [PMID: 31327284 DOI: 10.1080/10543406.2019.1632871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
When testing for superiority in a parallel-group setting with a continuous outcome, adjusting for covariates is usually recommended. For this purpose, the analysis of covariance is frequently used, and recently several exact and approximate sample size calculation procedures have been proposed. However, in case of multiple covariates, the planning might pose some practical challenges and pitfalls. Therefore, we propose a method, which allows for blinded re-estimation of the sample size during the course of the trial. Simulations confirm that the proposed method provides reliable results in many practically relevant situations, and applicability is illustrated by a real-life data example.
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Schraml M, Sommer F, Pur B, Köhler W, Zimmermann G, Witusiewicz VT, Sturz L. Measurement of non-isothermal transport coefficients in a near-eutectic succinonitrile/(d)camphor mixture. J Chem Phys 2019; 150:204508. [PMID: 31153215 DOI: 10.1063/1.5098879] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have determined nonisothermal diffusive transport coefficients of a succinonitrile-(d)camphor mixture with a composition of c = 0.239 wt.-frac. (d)camphor at a temperature of 318.2 K, which is close to the eutectic point. The employed experimental techniques are optical beam deflection in a Soret cell and photon correlation spectroscopy. The diffusion coefficient is D = (1.43 ± 0.04) × 10-10 m2 s-1, the thermodiffusion coefficient is DT = (2.00 ± 0.06) × 10-12 m2 s-1 K-1, and the Soret coefficient is ST = (1.40 ± 0.02) × 10-2 K-1. Camphor migrates toward the lower and succinonitrile migrates toward the higher temperatures. While the diffusion coefficient is in good agreement with the literature, the Soret coefficient has been determined for the first time. Our analysis shows that a significant concentration shift can be established in the liquid mixture in the presence of a temperature gradient. The mixture has a negative separation ratio, which leads to convective instabilities if heated from above.
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Zimmermann G, Pauly M, Bathke AC. Small-sample performance and underlying assumptions of a bootstrap-based inference method for a general analysis of covariance model with possibly heteroskedastic and nonnormal errors. Stat Methods Med Res 2019; 28:3808-3821. [PMID: 30600769 DOI: 10.1177/0962280218817796] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It is well known that the standard F test is severely affected by heteroskedasticity in unbalanced analysis of covariance models. Currently available potential remedies for such a scenario are based on heteroskedasticity-consistent covariance matrix estimation (HCCME). However, the HCCME approach tends to be liberal in small samples. Therefore, in the present paper, we propose a combination of HCCME and a wild bootstrap technique, with the aim of improving the small-sample performance. We precisely state a set of assumptions for the general analysis of covariance model and discuss their practical interpretation in detail, since this issue may have been somewhat neglected in applied research so far. We prove that these assumptions are sufficient to ensure the asymptotic validity of the combined HCCME-wild bootstrap analysis of covariance. The results of our simulation study indicate that our proposed test remedies the problems of the analysis of covariance F test and its heteroskedasticity-consistent alternatives in small to moderate sample size scenarios. Our test only requires very mild conditions, thus being applicable in a broad range of real-life settings, as illustrated by the detailed discussion of a dataset from preclinical research on spinal cord injury. Our proposed method is ready-to-use and allows for valid hypothesis testing in frequently encountered settings (e.g., comparing group means while adjusting for baseline measurements in a randomized controlled clinical trial).
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Leitinger M, Trinka E, Giovannini G, Zimmermann G, Florea C, Rohracher A, Kalss G, Neuray C, Kreidenhuber R, Höfler J, Kuchukhidze G, Granbichler C, Dobesberger J, Novak HF, Pilz G, Meletti S, Siebert U. Epidemiology of status epilepticus in adults: A population-based study on incidence, causes, and outcomes. Epilepsia 2018; 60:53-62. [PMID: 30478910 PMCID: PMC7380005 DOI: 10.1111/epi.14607] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/24/2018] [Accepted: 10/24/2018] [Indexed: 11/28/2022]
Abstract
Objective In 2015, the International League Against Epilepsy (ILAE) proposed a new definition of status epilepticus (SE): 5 minutes of ongoing seizure activity to diagnose convulsive SE (CSE, ie, bilateral tonic–clonic SE) and 10 minutes for focal SE and absence SE, rather than the earlier criterion of 30 minutes. Based on semiology, several types of SE with prominent motor phenomena at any time (including CSE) were distinguished from those without (ie, nonconvulsive SE, NCSE). We present the first population‐based incidence study applying the new 2015 ILAE definition and classification of SE and report the impact of the evolution of semiology and level of consciousness (LOC) on outcome. Methods We conducted a retrospective population‐based incidence study of all adult patients with SE residing in the city of Salzburg between January 2011 and December 2015. Patients with hypoxic encephalopathy were excluded. SE was defined and classified according to the ILAE 2015. Results We identified 221 patients with a median age of 69 years (range 20‐99 years). The age‐ and sex‐adjusted incidence of a first episode of SE, NCSE, and SE with prominent motor phenomena (including CSE) was 36.1 (95% confidence interval [CI] 26.2‐48.5), 12.1 (95% CI 6.8‐20.0), and 24.0 (95% CI 16.0‐34.5; including CSE 15.8 [95% CI 9.4‐24.8]) per 100 000 adults per year, respectively. None of the patients whose SE ended with or consisted of only bilateral tonic–clonic activity died. In all other clinical presentations, case fatality was lower in awake patients (8.2%) compared with patients with impaired consciousness (33%). Significance This first population‐based study using the ILAE 2015 definition and classification of SE found an increase of incidence of 10% compared to previous definitions. We also provide epidemiologic evidence that different patterns of status evolution and LOCs have strong prognostic implications.
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Kobulashvili T, Kuchukhidze G, Brigo F, Zimmermann G, Höfler J, Leitinger M, Dobesberger J, Kalss G, Rohracher A, Neuray C, Wakonig A, Ernst F, Braun KPJ, Mouthaan BE, Van Eijsden P, Ryvlin P, Cross JH, Trinka E. Diagnostic and prognostic value of noninvasive long-term video-electroencephalographic monitoring in epilepsy surgery: A systematic review and meta-analysis from the E-PILEPSY consortium. Epilepsia 2018; 59:2272-2283. [PMID: 30511441 DOI: 10.1111/epi.14598] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 10/16/2018] [Accepted: 10/17/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The European Union-funded E-PILEPSY network (now continuing within the European Reference Network for rare and complex epilepsies [EpiCARE]) aims to harmonize and optimize presurgical diagnostic procedures by creating and implementing evidence-based guidelines across Europe. The present study evaluates the current evidence on the diagnostic accuracy of long-term video-electroencephalographic monitoring (LTM) in identifying the epileptogenic zone in epilepsy surgery candidates. METHODS MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov were searched for relevant articles. First, we used random-effects meta-analytical models to calculate pooled estimates of sensitivity and specificity with respect to postsurgical seizure freedom. In a second phase, we analyzed individual patient data in an exploratory fashion, assessing diagnostic accuracy within lesional and nonlesional temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE) patients. We also evaluated seizure freedom rate in the presence of "localizing" or "nonlocalizing" LTM within each group. The quality of evidence was assessed using the QUADAS-2 tool and the GRADE approach. RESULTS Ninety-four studies were eligible. Forty-four were included in sensitivity meta-analysis and 34 in specificity meta-analysis. Pooled sensitivity was 0.70 (95% confidence interval [CI] = 0.60-0.80) and specificity was 0.40 (95% CI = 0.27-0.54). Subgroup analysis was based on individual data of 534 patients (41% men). In lesional TLE patients, sensitivity was 0.85 (95% CI = 0.81-0.89) and specificity was -0.19 (95% CI = 0.13-0.28). In lesional ETLE patients, a sensitivity of 0.47 (95% CI = 0.36-0.58) and specificity of 0.35 (95% CI = 0.21-0.53) were observed. In lesional TLE, if LTM was localizing and concordant with resection site, the seizure freedom rate was 247 of 333 (74%), whereas in lesional ETLE it was 34 of 56 (61%). The quality of evidence was assigned as "very low." SIGNIFICANCE Long-term video-electroencephalographic monitoring is associated with moderate sensitivity and low specificity in identification of the epileptogenic zone. Sensitivity is remarkably higher in lesional TLE compared to lesional ETLE. Substantial heterogeneity across the studies indicates the need for improved design and quality of reporting.
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Schmid E, Thomschewski A, Taylor A, Zimmermann G, Kirschner M, Kobulashvili T, Brigo F, Rados M, Helmstaedter C, Braun K, Trinka E. Diagnostic accuracy of functional magnetic resonance imaging, Wada test, magnetoencephalography, and functional transcranial Doppler sonography for memory and language outcome after epilepsy surgery: A systematic review. Epilepsia 2018; 59:2305-2317. [PMID: 30374948 DOI: 10.1111/epi.14588] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/27/2018] [Indexed: 12/01/2022]
Abstract
OBJECTIVE The European Union-funded E-PILEPSY project was launched to develop guidelines and recommendations for epilepsy surgery. In this systematic review, we aimed to assess the diagnostic accuracy of functional magnetic resonance imaging (fMRI), Wada test, magnetoencephalography (MEG), and functional transcranial Doppler sonography (fTCD) for memory and language decline after surgery. METHODS The literature search was conducted using PubMed, Embase, and CENTRAL. The diagnostic accuracy was expressed in terms of sensitivity and specificity for postoperative language or memory decline, as determined by pre- and postoperative neuropsychological assessments. If two or more estimates of sensitivity or specificity were extracted from a study, two meta-analyses were conducted, using the maximum ("best case") and the minimum ("worst case") of the extracted estimates, respectively. RESULTS Twenty-eight papers were eligible for data extraction and further analysis. All tests for heterogeneity were highly significant, indicating large between-study variability (P < 0.001). For memory outcomes, meta-analyses were conducted for Wada tests (n = 17) using both memory and language laterality quotients. In the best case, meta-analyses yielded a sensitivity estimate of 0.79 (95% confidence interval [CI] = 0.67-0.92) and a specificity estimate of 0.65 (95% CI = 0.47-0.83). For the worst case, meta-analyses yielded a sensitivity estimate of 0.65 (95% CI = 0.48-0.82) and a specificity estimate of 0.46 (95% CI = 0.28-0.65). The overall quality of evidence, which was assessed using Grading of Recommendations Assessment, Development, and Evaluation methodology, was rated as very low. Meta-analyses concerning diagnostic accuracy of fMRI, fTCD, and MEG were not feasible due to small numbers of studies (fMRI, n = 4; fTCD, n = 1; MEG, n = 0). This also applied to studies concerning language outcomes (Wada test, n = 6; fMRI, n = 2; fTCD, n = 1; MEG, n = 0). SIGNIFICANCE Meta-analyses could only be conducted in a few subgroups for the Wada test with low-quality evidence. Thus, more evidence from high-quality studies and improved data reporting are required. Moreover, the large between-study heterogeneity underlines the necessity for more homogeneous and thus comparable studies in future research.
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Schneider AM, Weghuber D, Hetzer B, Entenmann A, Müller T, Zimmermann G, Schütz S, Huber WD, Pichler J. Vedolizumab use after failure of TNF-α antagonists in children and adolescents with inflammatory bowel disease. BMC Gastroenterol 2018; 18:140. [PMID: 30219028 PMCID: PMC6139155 DOI: 10.1186/s12876-018-0868-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 09/03/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Vedolizumab is safe and effective in adult patients with Crohn's disease (CD) and ulcerative colitis (UC); however, data in children with inflammatory bowel disease (IBD) are scarce. Therefore, we evaluated vedolizumab use in a cohort of Austrian paediatric patients with IBD. METHODS Twelve patients (7 female; 7 CD; 5 UC), aged 8-17 years (median, 15 years), with severe IBD who received vedolizumab after tumour necrosis factor α antagonist treatment were retrospectively analysed. Clinical activity scores, relevant laboratory parameters, and auxological measures were obtained at infusion visits. RESULTS In the CD group, 1/7 patient discontinued therapy due to a severe systemic allergic reaction; 1/7 and 2/7 patients achieved complete and partial response, respectively, at week 14; and 3/7 patients discontinued therapy due to a primary non-response or loss of response. In the UC group, complete clinical remission was achieved at weeks 2, 6, and 14 in 2/5, 1/5 and 1/5 patients respectively; partial response was observed in one patient at week 2. CD activity scores did not significantly change from baseline to week 38 (median 47.5 vs. 40 points, p = 1,0), while median UC activity scores changed from 70 to 5 points (p < 0,001). Substantial weight gain and increased albumin and haemoglobin levels were observed in both groups. CONCLUSION These results demonstrate that vedolizumab can be an effective treatment for individual paediatric patients with IBD who are unresponsive, intolerant, or experience a loss of efficacy in other therapies. However, vedolizumab appears to be more effective in paediatric UC than in paediatric CD.
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Rohracher A, Zimmermann G, Villanueva V, Garamendi I, Sander JW, Wehner T, Shankar R, Ben-Menachem E, Brodie MJ, Pensel MC, Di Gennaro G, Maurousset A, Strzelczyk A, Rheims S, Rácz A, Menzler K, Bertol-Alegre V, García-Morales I, López-González FJ, Toledo M, Carpenter KJ, Trinka E. Perampanel in routine clinical use across Europe: Pooled, multicenter, observational data. Epilepsia 2018; 59:1727-1739. [DOI: 10.1111/epi.14520] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/02/2018] [Indexed: 12/28/2022]
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Dobesberger J, Höfler J, Leitinger M, Kuchukhidze G, Zimmermann G, Thomschewski A, Unterberger I, Walser G, Kalss G, Rohracher A, Neuray C, Kobulashvili T, Höller Y, Trinka E. Personalized safety measures reduce the adverse event rate of long-term video EEG. Epilepsia Open 2018; 2:400-414. [PMID: 29588971 PMCID: PMC5862109 DOI: 10.1002/epi4.12078] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2017] [Indexed: 11/07/2022] Open
Abstract
Objective Safety in epilepsy monitoring units (EMUs) has become an increasing concern because adverse events occur in up to 10% of patients undergoing long‐term video EEG in EMUs. The aim of this study was to assess the effectiveness of a specific safety protocol in an EMU. Methods We retrospectively assessed the adverse event rates in a group without (group 1, 84‐month period, Innsbruck, Austria) and a group with (group 2, 33‐month period, Salzburg, Austria) personalized safety measures utilizing a standardized protocol for long‐term epilepsy monitoring in high‐risk patients. Differences in adverse event rates during and after long‐term video EEG between the two groups were calculated and compared. Results In group 1, 44/507 (9%, 95% confidence interval [CI] 6.5–11.5%) patients experienced 53 adverse events: 20/507 (4%, 95% CI 2.6–6.0%) patients had psychiatric events, 15/507 (3%, 95% CI 1.8–4.8%) patients sustained a total of 19 injuries during seizures, and 10/507 (2%, 95% CI 1.1–3.6%) patients had 13 episodes of status epilepticus; one adverse event was treatment‐related (valproic acid–induced encephalopathy; 1/507, 0.2%, 95% CI 0.0–1.1%). By using the new safety protocol in group 2, the adverse event rate was only 5% (95% CI 3.4–7.6%; 30 adverse events in 26/491; 45% reduction; p = 0.036), in contrast. These events included 13 psychiatric complications in 13/491 (2%, 95% CI 1.6–4.5%, p = 0.252) patients, 12 seizure‐related injuries in 9/491 (2%, 95% CI 1.0–3.4%, p = 0.250) patients, and 5 episodes of status epilepticus in 4/491 (1%, 95% CI 0.3–2.1%, p = 0.120) patients. Significance Implementation of personalized safety measures in high‐risk patients resulted in a clinically relevant reduction of adverse events in the EMU. Safety protocols are a valid tool to reduce the occurrence of adverse events in EMUs.
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