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NeuroImage. Clinical 2022Voxelwise disconnection mapping is a novel approach to disclose lesion-symptom relationships for symptoms caused by white matter disconnection. It uses MRI-based fiber...
Voxelwise disconnection mapping is a novel approach to disclose lesion-symptom relationships for symptoms caused by white matter disconnection. It uses MRI-based fiber tracking in healthy subjects seeded from patient's focal brain lesions. Resulting individual disconnection maps can then be statistically associated with symptoms. Despite increasing use in the recent years, the validity of this approach remains to be investigated. In this study, we validated both, our own implementation and the implementation provided within BCBtoolkit. For technical validation, we used simulated symptoms based on overlap of 70 real stroke lesions with tracts from a white matter atlas. For clinical validation, paresis scores and lesions from 316 patients with stroke were used. We found that voxelwise disconnection mapping is technically valid and outperforms the standard voxel-based lesion-symptom mapping approach for symptoms caused by white matter disconnection. Supporting its clinical validity and utility, we were able to reproduce the known association between corticospinal tract damage and contralateral hemiparesis. In addition, we demonstrate that the validity can be substantially diminished by relatively minor methodological changes. Based on these results, we derive methodological recommendations for the future use of voxelwise disconnection mapping. Our study highlights the importance of validating novel methodological approaches in the rapidly evolving field of neuroimaging.
Topics: Brain; Brain Mapping; Humans; Magnetic Resonance Imaging; Neuroimaging; Pyramidal Tracts; Stroke; White Matter
PubMed: 36002968
DOI: 10.1016/j.nicl.2022.103132 -
Journal of Surgical Education 2014The purpose of this study is to (1) systematically review all the literature pertaining to microsurgical training models and to (2) determine which of these are specific... (Review)
Review
OBJECTIVES
The purpose of this study is to (1) systematically review all the literature pertaining to microsurgical training models and to (2) determine which of these are specific to and validated for microsurgery training.
DESIGN
PubMed, MEDLINE (OVID/EBSCO), Google Scholar, and Cochrane Central Register of Controlled Trials were searched using preset terms. The last search date was in July 2012. Articles of all languages, years of publication, sample sizes, and model types pertaining to microsurgery were included. The eligibility criteria included the use of a microsurgical training model on a subject group with statistical analysis and measures of validation. Two assessors independently reviewed the articles and their references.
RESULTS
Of the 238 articles reviewed, 9 articles met the criteria. Those excluded were predominantly model descriptions that had not been validated in a set of learners. The 9 models whose performances were assessed in a group of learners included an online curriculum, nonliving prosthetics and biologics, and the live rat femoral artery model. Each model was evaluated for content, construct, face, and criterion (concurrent and predictive) validity, as well as selection and observation/expectant bias. Content, construct, concurrent, and face validities were consistently demonstrated for all 9 models. Selection bias was also reliably well controlled with random allocation of participants to each study group. Observation/expectant bias was controlled in 6 of the 8 papers. Predictive validity, an arguably more difficult factor to measure, was only present in 1 article.
CONCLUSIONS
Despite a plethora of papers describing microsurgical learning tools, only 9 were discovered that provided validation of the proposed method of microsurgical skills acquisition. This review depicts the need for basic, yet well-designed studies that substantiate the effectiveness of microsurgical training models by using a subject group and demonstrating a statistical improvement with employment of the model. Ease of access, cost, and assessment tools used also require attention.
Topics: Animals; Microsurgery; Models, Animal; Models, Theoretical
PubMed: 24797848
DOI: 10.1016/j.jsurg.2013.09.008 -
Chronic Diseases and Injuries in Canada Feb 2014Despite the widespread use of deprivation indices in public health, they are rarely explicitly or extensively validated, owing to the complex nature of the exercise. (Review)
Review
INTRODUCTION
Despite the widespread use of deprivation indices in public health, they are rarely explicitly or extensively validated, owing to the complex nature of the exercise.
METHODS
Based on the proposals of British researchers, we sought to validate Quebec's material and social deprivation index using criteria of validity (content, criterion and construct validity), reliability and responsiveness, as well as other properties relevant to public health (comprehensibility, objectivity and practicality).
RESULTS
We reviewed the international literature on deprivation indices, as well as publications and uses of the Quebec index, to which we added factual data.
CONCLUSION
Based on the review, it appears that the Quebec index responds favourably to the proposed validation criteria and properties. However, additional validations are required to better identify the contextual factors associated with the index.
Topics: Female; Health Status Disparities; Humans; Male; Needs Assessment; Poverty; Psychosocial Deprivation; Public Health; Quebec; Reproducibility of Results; Risk Assessment; Small-Area Analysis; Socioeconomic Factors
PubMed: 24618377
DOI: No ID Found -
Validation and validity of diagnoses in the General Practice Research Database: a systematic review.British Journal of Clinical Pharmacology Jan 2010To investigate the range of methods used to validate diagnoses in the General Practice Research Database (GPRD), to summarize findings and to assess the quality of these... (Review)
Review
AIMS
To investigate the range of methods used to validate diagnoses in the General Practice Research Database (GPRD), to summarize findings and to assess the quality of these validations.
METHODS
A systematic literature review was performed by searching PubMed and Embase for publications using GPRD data published between 1987 and April 2008. Additional publications were identified from conference proceedings, back issues of relevant journals, bibliographies of retrieved publications and relevant websites. Publications that reported attempts to validate disease diagnoses recorded in the GPRD were included.
RESULTS
We identified 212 publications, often validating more than one diagnosis. In total, 357 validations investigating 183 different diagnoses met our inclusion criteria. Of these, 303 (85%) utilized data from outside the GPRD to validate diagnoses. The remainder utilized only data recorded in the database. The median proportion of cases with a confirmed diagnosis was 89% (range 24-100%). Details of validation methods and results were often incomplete.
CONCLUSIONS
A number of methods have been used to assess validity. Overall, estimates of validity were high. However, the quality of reporting of the validations was often inadequate to permit a clear interpretation. Not all methods provided a quantitative estimate of validity and most methods considered only the positive predictive value of a set of diagnostic codes in a highly selected group of cases. We make recommendations for methodology and reporting to strengthen further the use of the GPRD in research.
Topics: Algorithms; Clinical Competence; Databases, Factual; Diagnostic Errors; Family Practice; Humans; Reproducibility of Results; Research; Surveys and Questionnaires
PubMed: 20078607
DOI: 10.1111/j.1365-2125.2009.03537.x -
Current Clinical Pharmacology May 2007The International Conference of Harmonisation (ICH) Guideline E9 Statistics Principles for Clinical Trials recommends that surrogate endpoints in clinical trials be... (Review)
Review
BACKGROUND
The International Conference of Harmonisation (ICH) Guideline E9 Statistics Principles for Clinical Trials recommends that surrogate endpoints in clinical trials be validated using either (1) the sensitivity-specificity approach or (2) regression analysis. The problem with (1) is that an overall level of validity is hard to achieve, and with (2) is that a significant correlation between the surrogate and true endpoint is not enough to indicate that the surrogate is a valid predictor.
OBJECTIVE
To provide for a nonmathematical readership, procedures that avoid the above two problems.
RESULTS AND CONCLUSIONS
1. Instead of the sensitivity-specificity approach, we used an overall validity level, expressed as the percentage of patients with a true surrogate test, either positive or negative. We calculated confidence intervals of this estimate, and assessed whether they were entirely within the prespecified interval of validity. If so, the surrogate marker was validated for use in subsequent trials. 2. For validating continuous surrogate variables, regression analysis was used, accounting for both the correlation between the surrogate and true endpoints, and the associations between these two variables and the treatment modalities to be tested. If the proportion of variability in the surrogate endpoint explained the true endpoint by 70% or more, the surrogate test was validated. A wrong conclusion here would be to accept validity if the surrogate endpoint was an independent determinant of the true endpoint, but not of the treatment modality. It is to be hoped that this paper will affect the validity of future clinical trials constructed with surrogate endpoints.
Topics: Clinical Trials as Topic; Endpoint Determination; Humans; Models, Statistical; Regression Analysis; Reproducibility of Results; Research Design; Sample Size; Terminology as Topic
PubMed: 18690859
DOI: 10.2174/157488407780598126 -
Applied Biosafety : Journal of the... Mar 2021Part 1 of this two-part series describes the use of hydrogen peroxide as a fumigant and compares it with other fumigants on the market. Technical requirements are... (Review)
Review
Part 1 of this two-part series describes the use of hydrogen peroxide as a fumigant and compares it with other fumigants on the market. Technical requirements are outlined while considering physical and biological limitations of the system. This second part focuses primarily on the use of process controls to verify and validate hydrogen peroxide fumigations. Finally, a model encompassing the entire fumigation process is presented. Part 2 of the series focuses on the authors' long-time personal experiences in room and filter fumigation using various fumigation systems and is supplemented with relevant literature searches. The reader is introduced to the planning and implementation of fumigation process validations. Biological indicators help users develop safe and efficient processes. Chemical indicators can be used as process controls, while measuring physical parameters will help avoid condensation of hydrogen peroxide. How many biological and chemical indicators and what type should be applied for cycle development are additionally explained. It is important to consider numerous technical requirements when planning to implement hydrogen peroxide fumigation at an institution. Also, considerable thought needs to go into the verification and validation of the fumigation process. Part 1 of this series presents an overview of different fumigation systems based on hydrogen peroxide on the market and their technical requirements. Part 2 focuses on validation and verification of hydrogen peroxide fumigation while considering the entire fumigation process. The two parts together will serve users as a guide to establishing hydrogen peroxide fumigations at their facilities.
PubMed: 36033965
DOI: 10.1089/apb.21.921099 -
Neurogastroenterology and Motility Sep 2012In the absence of a clear biomarker for irritable bowel syndrome (IBS), clinical criteria are used. In this study, we conduct a systematic review to examine the... (Review)
Review
BACKGROUND
In the absence of a clear biomarker for irritable bowel syndrome (IBS), clinical criteria are used. In this study, we conduct a systematic review to examine the validation and utilization of IBS criteria.
METHODS
A systematic review was performed in two stages. The first was a review of literature from 1978 validating IBS diagnostic criteria. The second stage of review was to select studies published in IBS between 1992 and 2011. This time period was divided into three segments (Rome I era from 1992 to 1999, Rome II era from 2000 to 2006, and Rome III era from 2007 to 2011). The number and type of study (RCT or other) and criteria used were evaluated for each era.
KEY RESULTS
The first stage of the systematic review identified only 14 published studies validating diagnostic tests for IBS (with three studies evaluating more than one criterion). There were eight validations for Manning, three validations for Kruis, four validations for Rome I, three validations for Rome II, and no validation for Rome III. In the second review of utilization of Rome criteria, only 25.7% of published IBS papers used Rome III criteria during the Rome III era (Rome II was used most in 64.8% of studies).
CONCLUSIONS & INFERENCES
This review identified that comparator groups varied widely between studies making comparison of criteria impossible. Manning criteria are the most valid and accurate criteria. More importantly, Rome III is not validated and is poorly adopted in clinical research trial enrollment.
Topics: Guideline Adherence; Humans; Irritable Bowel Syndrome; Reproducibility of Results
PubMed: 22632582
DOI: 10.1111/j.1365-2982.2012.01943.x -
The Journal of Nursing Administration May 1997The goal of this study was to develop a method to scientifically create and validate a coordinated care path for use within any hospital setting.
OBJECTIVE
The goal of this study was to develop a method to scientifically create and validate a coordinated care path for use within any hospital setting.
BACKGROUND
In an attempt to reduce the costs associated with high-volume and high-risk diagnosis, attention was focused on reducing patients' length of stay in the hospital. A method to reduce length of stay uses a coordinated care path. A path is a guideline used to manage the clinical care of selected patients. The literature is relatively silent regarding studies that have scientifically validated the use of these paths.
METHODS
This project used a content validity method to validate the care path. Using current research findings, best practice standards both locally and nationally, a transdisciplinary team developed practice guidelines that included sequencing, timing of interventions, and expected patient outcomes. The path was rated by local and national experts using a four-point rating scale. Using Lynn's proportion of experts table computations, the validity of the path and each of its components was determined.
RESULTS
Of 161 items on the care path, 10 were not validated. The experts validated the instrument as a whole. Of the 161 items, 151 were validated. This is an instrument validation rate of 0.94. No additional changes or modifications to the path were suggested by the experts. The transdisciplinary team addressed the nonvalidated items. This method can be used to develop other coordinated paths for other diagnostic groups.
Topics: Critical Pathways; Evidence-Based Medicine; Hospitalization; Humans; Patient Care Team; Practice Guidelines as Topic; Reproducibility of Results; Schizophrenia; United States
PubMed: 9159613
DOI: 10.1097/00005110-199705000-00009 -
Journal of Chromatography. B,... Nov 1996Validations of analytical methods are important for the generation of data for bioavailability, bioequivalence and pharmacokinetic studies. It is essential to use well... (Review)
Review
Validations of analytical methods are important for the generation of data for bioavailability, bioequivalence and pharmacokinetic studies. It is essential to use well defined and fully validated analytical methods to obtain reliable results that can be satisfactorily interpreted. This manuscript is intended to provide guiding principles for the evaluation of a method's overall performance. For this purpose, all of the variables of the method are considered, including sampling procedure, sample preparation, chromatographic separation, detection and data evaluation. The criteria considered are as follows: stability, selectivity, limits of quantification and of detection, accuracy, precision, linearity, recovery and ruggedness. Models used for analytical calibration curves are explained in term of validity and limitations, along with a presentation of the most common statistical considerations used to validate the model. Appropriate means of testing precision and accuracy, the most important factors in assessing method quality, are presented. Other issues, such as re-validation, cross-validation, partial sample volume, endogenous drugs and biological matrix of limited availability, are also discussed.
Topics: Calibration; Chromatography, Gas; Chromatography, Liquid; Pharmacokinetics; Quality Control; Reproducibility of Results; Sensitivity and Specificity
PubMed: 8953186
DOI: 10.1016/s0378-4347(96)00088-6 -
Depression and Anxiety 2008Generalized anxiety disorder (GAD) has undergone a series of revisions in its diagnostic criteria that has moved it, nosologically, away from its original affiliation... (Review)
Review
Generalized anxiety disorder (GAD) has undergone a series of revisions in its diagnostic criteria that has moved it, nosologically, away from its original affiliation with panic disorder (PD) and closer to major depressive disorder (MDD). This, together with its high comorbidity and putative shared genetic risk with MDD, has brought into question its place in future psychiatric nosology, prompting the planners of Diagnostic and Statistical Manual-V (DSM-V) and International Classification of Diseases-11 (ICD-11) to set up a workgroup tasked to better understand the relationship between GAD and MDD. This review attempts to summarize the extant data to compare GAD and MDD on a series of research validators to explore this relationship. Although insufficient data currently exist for GAD in several key validator classes, tentative conclusions can be drawn on the diagnostic status of GAD in relation to MDD. Although GAD possesses substantial overlap with MDD in the areas of genetics, childhood environment, demographics, and personality traits, this tends to hold true for other anxiety disorders (ADs) as well, with the strongest evidence for PD. Data from life events, personality disorders, biology, comorbidity, and pharmacology are mixed, showing some areas of similarity between GAD and MDD but some clear differences, again with a moderate degree of nonspecificity. Thus, although the bulk of evidence supports a close underlying relationship between them, the relatively nonspecific nature of these findings provides little more reason to question the nosologic validity of GAD in relation to MDD than that of some other anxiety disorders.
Topics: Anxiety Disorders; Comorbidity; Depressive Disorder, Major; Diagnostic and Statistical Manual of Mental Disorders; Humans; Panic Disorder
PubMed: 18412057
DOI: 10.1002/da.20491