Against coefficient of variation for estimation of intraindividual variability with accuracy measures

Previous studies have shown that intraindividual variability (iV) in performance is an important indicator of individual's cognitive functioning and neurological integrity. While most experiments have examined iV of performance using Reaction Time data (RTs), few studies have considered it with accuracy measures (e.g. number / percentage of correct responses). For these two types of measures, intraindividual standard deviation (iSD) or intraindividual coefficient of variation (iCV; intraindividual standard deviation divided by the individual mean) were used as indicators of iV in performance. However, because accuracy data have a lower and an upper bound (in contrast to RTs), we illustrate both formally and with simulated data, that the iCV cannot be used with accuracy measures. We also show that the coefficient iCV is influenced by the number of items which is an issue when dealing with missing data. We further provide formulas that may help researchers to visualize and correctly interpret their data using any spreadsheet software. The current article finally proposes an alternative coefficient (zeta) to examine iV in performance with accuracy measures that shows similar behaviour as does iCV with RTs data

Against coefficient of variation for estimation of intraindividual variability with accuracy measures

Previous studies have shown that intraindividual variability (iV) in performance is an important indicator of individuals cognitive functioning and neurological integrity. While most experiments have examined iV of performance using Reaction Time data (RTs), few studies have considered it with accuracy measures (e.g. number or percentage of correct responses). For these two types of measures, intraindividual standard deviation (iSD) or intraindividual coefficient of variation (iCV; intraindividual standard deviation divided by the individual mean) were used as indicators of iV in performance. However, because accuracy data have a lower and an upper bound (in contrast to RTs), we illustrate both formally and with simulated data, that the iCV cannot be used with accuracy measures. We also show that the coefficient iCV is influenced by the number of items which is an issue when dealing with missing data. We further provide formulas that may help researchers to visualize and correctly interpret their data using any spreadsheet software. The current article finally proposes an alternative coefficient (zeta) to examine iV in performance with accuracy measures that shows similar behaviour as does iCV with RTs data

Cohort Profile: The Swiss Eosinophilic Esophagitis Cohort Study (SEECS).

The prospective, observational Swiss Eosinophilic Esophagitis Cohort Study (SEECS) was set up in 2015 with the following goals in mind: (1) to provide up-to-date epidemiologic data; (2) to assess the appropriateness of care; (3) to evaluate the psychosocial impact; and (4) to foster translational research projects. Data capture relies on validated instruments to assess disease activity and focuses on epidemiologic variables and biosamples (esophageal biopsies and blood specimens). An annual inclusion of 70 new patients with eosinophilic esophagitis (EoE) or proton pump inhibitor-responsive esophageal eosinophilia (PPI-REE) is intended. We herein describe the SEECS cohort profile. The SEECS includes adult patients (age ≥18 years) with EoE or PPI-REE diagnosed according to published criteria. After inclusion, the patients are typically seen once a year for a clinical and endoscopic/histologic follow-up examination. Data are captured using validated questionnaires. Biosamples from patients with gastroesophageal reflux disease (GERD) and controls with a healthy esophagus are collected as well. From January 2016 to July 2017, a total of 111 patients with EoE and 10 patients with PPI-REE were recruited. In addition, esophageal biopsies and blood samples from 11 patients with GERD and 20 controls with a healthy esophagus were collected. The mean age of the patients with EoE and those with PPI-REE was 39.6 ± 12.9 and 44.6 ± 15.6 years, respectively. A male predominance was found among both the patients with EoE (77.5%) and those with PPI-REE (70%). Concomitant allergic disorders were found in 79.3% of the patients with EoE and 90% of the patients with PPI-REE. At inclusion, the EoE patients were treated with the following therapeutic regimens: no therapy (0.9%), PPI (36%), swallowed topical corticosteroids (82.9%), elimination diets (15.3%), and esophageal dilation (19.8%). The SEECS is the first national cohort study of patients with EoE or PPI-REE. The SEECS will provide up-to-date epidemiologic data and foster translational research projects

Somatic mosaicism and common genetic variation contribute to the risk of very-early-onset inflammatory bowel disease

Very-early-onset inflammatory bowel disease (VEO-IBD) is a heterogeneous phenotype associated with a spectrum of rare Mendelian disorders. Here, we perform whole-exome-sequencing and genome-wide genotyping in 145 patients (median age-at-diagnosis of 3.5 years), in whom no Mendelian disorders were clinically suspected. In five patients we detect a primary immunodeficiency or enteropathy, with clinical consequences (XIAP, CYBA, SH2D1A, PCSK1). We also present a case study of a VEO-IBD patient with a mosaic de novo, pathogenic allele in CYBB. The mutation is present in ~70% of phagocytes and sufficient to result in defective bacterial handling but not life-threatening infections. Finally, we show that VEO-IBD patients have, on average, higher IBD polygenic risk scores than population controls (99 patients and 18,780 controls; P < 4 × 10-10), and replicate this finding in an independent cohort of VEO-IBD cases and controls (117 patients and 2,603 controls; P < 5 × 10-10). This discovery indicates that a polygenic component operates in VEO-IBD pathogenesis