Nicole R. Karcher

Bio: Nicole R. Karcher is an academic researcher from Washington University in St. Louis. The author has contributed to research in topics: Medicine & Psychology. The author has an hindex of 12, co-authored 43 publications receiving 595 citations. Previous affiliations of Nicole R. Karcher include University of Missouri & College of William & Mary.

Cognitive Deficits in Psychotic Disorders: A Lifespan Perspective.

Abstract: Individuals with disorders that include psychotic symptoms (i.e. psychotic disorders) experience broad cognitive impairments in the chronic state, indicating a dimension of abnormality associated with the experience of psychosis. These impairments negatively impact functional outcome, contributing to the disabling nature of schizophrenia, bipolar disorder, and psychotic depression. The robust and reliable nature of cognitive deficits has led researchers to explore the timing and profile of impairments, as this may elucidate different neurodevelopmental patterns in individuals who experience psychosis. Here, we review the literature on cognitive deficits across the life span of individuals with psychotic disorder and psychotic-like experiences, highlighting the dimensional nature of both psychosis and cognitive ability. We identify premorbid generalized cognitive impairment in schizophrenia that worsens throughout development, and stabilizes by the first-episode of psychosis, suggesting a neurodevelopmental course. Research in affective psychosis is less clear, with mixed evidence regarding premorbid deficits, but a fairly reliable generalized deficit at first-episode, which appears to worsen into the chronic state. In general, cognitive impairments are most severe in schizophrenia, intermediate in bipolar disorder, and the least severe in psychotic depression. In all groups, cognitive deficits are associated with poorer functional outcome. Finally, while the generalized deficit is the clearest and most reliable signal, data suggests specific deficits in verbal memory across all groups, specific processing speed impairments in schizophrenia and executive functioning impairments in bipolar disorder. Cognitive deficits are a core feature of psychotic disorders that provide a window into understanding developmental course and risk for psychosis.

Associations between Prenatal Cannabis Exposure and Childhood Outcomes: Results from the ABCD Study

Abstract: Importance In light of increasing cannabis use among pregnant women, the US Surgeon General recently issued an advisory against the use of marijuana during pregnancy. Objective To evaluate whether cannabis use during pregnancy is associated with adverse outcomes among offspring. Design, Setting, and Participants In this cross-sectional study, data were obtained from the baseline session of the ongoing longitudinal Adolescent Brain and Cognitive Development Study, which recruited 11 875 children aged 9 to 11 years, as well as a parent or caregiver, from 22 sites across the United States between June 1, 2016, and October 15, 2018. Exposure Prenatal cannabis exposure prior to and after maternal knowledge of pregnancy. Main Outcomes and Measures Symptoms of psychopathology in children (ie, psychotic-like experiences [PLEs] and internalizing, externalizing, attention, thought, and social problems), cognition, sleep, birth weight, gestational age at birth, body mass index, and brain structure (ie, total intracranial volume, white matter volume, and gray matter volume). Covariates included familial (eg, income and familial psychopathology), pregnancy (eg, prenatal exposure to alcohol and tobacco), and child (eg, substance use) variables. Results Among 11 489 children (5997 boys [52.2%]; mean [SD] age, 9.9 [0.6] years) with nonmissing prenatal cannabis exposure data, 655 (5.7%) were exposed to cannabis prenatally. Relative to no exposure, cannabis exposure only before (413 [3.6%]) and after (242 [2.1%]) maternal knowledge of pregnancy were associated with greater offspring psychopathology characteristics (ie, PLEs and internalizing, externalizing, attention, thought and, social problems), sleep problems, and body mass index, as well as lower cognition and gray matter volume (all |β| > 0.02; all false discovery rate [FDR]–correctedP 0.02; all FDR-correctedP 0.02; FDR-correctedP .70). Conclusions and Relevance This study suggests that prenatal cannabis exposure and its correlated factors are associated with greater risk for psychopathology during middle childhood. Cannabis use during pregnancy should be discouraged.

Assessment of the prodromal questionnaire-brief child version for measurement of self-reported psychoticlike experiences in childhood

Abstract: Importance Childhood psychoticlike experiences (PLEs) are associated with greater odds of a diagnosis of a psychotic disorder during adulthood. However, no known, well-validated self-report tools have been designed to measure childhood PLEs. Objective To examine the construct validity and psychometric properties of a measure of PLEs, the Prodromal Questionnaire–Brief Child Version (PQ-BC). Design, Setting, and Participants This validation study used data from the first wave of the Adolescent Brain and Cognitive Development (ABCD) Study, a prospective longitudinal study aimed at assessing risk factors associated with adverse physical and mental health outcomes from ages 9 to 10 years into late adolescence and early adulthood. The population-based sample of 3984 children within the ABCD data set was recruited from 20 research sites across the United States. Data for this study were collected from June 1, 2016, through August 31, 2017. Main Outcomes and Measures The PQ-BC Total and Distress scores were analyzed for measurement invariance across race/ethnicity and sex, their associations with measures of PLEs, and their associations with known correlates of PLEs, including internalizing and externalizing symptoms, neuropsychological test performance, and developmental milestones. Results The study analyses included 3984 participants (1885 girls [47.3%] and 2099 boys [52.7%]; mean [SE] age, 10.0 [0.01] years). The results demonstrated measurement invariance across race/ethnicity and sex. A family history of psychotic disorder was associated with higher mean (SE) PQ-BC Total (3.883 [0.352]; β = 0.061; 95% CI, 0.027-0.094) and Distress (10.210 [1.043]; β = 0.051; 95% CI, 0.018-0.084) scores, whereas a family history of depression or mania was not. Higher PQ-BC scores were associated with higher rates of child-rated internalizing symptoms (Total score: β range, 0.218 [95% CI, 0.189-0.246] to 0.273 [95% CI, 0.245-0.301]; Distress score: β range, 0.248 [95% CI, 0.220-0.277] to 0.310 [95% CI, 0.281-0.338]), neuropsychological test performance deficits such as working memory (Total score: β = −0.042 [95% CI, −0.077 to −0.008]; Distress score: β = −0.051 [95% CI, −0.086 to −0.017]), and motor and speech developmental milestone delays (Total score: β = 0.057 [95% CI, 0.026-0.086] for motor; β = 0.042 [95% CI, 0.010-0.073] for speech; Distress score: β = 0.048 [95% CI, 0.017-0.079] for motor; β = 0.049 [95% CI, 0.018-0.081] for speech). Conclusions and Relevance These results provide support for the construct validity and demonstrate adequate psychometric properties of a self-report instrument designed to measure childhood PLEs, providing evidence that the PQ-BC may be a useful measure of early risk for psychotic disorders. Furthermore, these data suggest that PLEs at school age are associated with many of the same familial, cognitive, and emotional factors associated with psychotic symptoms in older populations, consistent with the dimensionality of psychosis across the lifespan.

An Introduction To The Event Related Potential Technique

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Reproducible brain-wide association studies require thousands of individuals

Abstract: Magnetic resonance imaging (MRI) has transformed our understanding of the human brain through well-replicated mapping of abilities to specific structures (for example, lesion studies) and functions1-3 (for example, task functional MRI (fMRI)). Mental health research and care have yet to realize similar advances from MRI. A primary challenge has been replicating associations between inter-individual differences in brain structure or function and complex cognitive or mental health phenotypes (brain-wide association studies (BWAS)). Such BWAS have typically relied on sample sizes appropriate for classical brain mapping4 (the median neuroimaging study sample size is about 25), but potentially too small for capturing reproducible brain-behavioural phenotype associations5,6. Here we used three of the largest neuroimaging datasets currently available-with a total sample size of around 50,000 individuals-to quantify BWAS effect sizes and reproducibility as a function of sample size. BWAS associations were smaller than previously thought, resulting in statistically underpowered studies, inflated effect sizes and replication failures at typical sample sizes. As sample sizes grew into the thousands, replication rates began to improve and effect size inflation decreased. More robust BWAS effects were detected for functional MRI (versus structural), cognitive tests (versus mental health questionnaires) and multivariate methods (versus univariate). Smaller than expected brain-phenotype associations and variability across population subsamples can explain widespread BWAS replication failures. In contrast to non-BWAS approaches with larger effects (for example, lesions, interventions and within-person), BWAS reproducibility requires samples with thousands of individuals.

Reproducible brain-wide association studies require thousands of individuals

Abstract: Magnetic resonance imaging (MRI) has transformed our understanding of the human brain through well-replicated mapping of abilities to specific structures (for example, lesion studies) and functions1-3 (for example, task functional MRI (fMRI)). Mental health research and care have yet to realize similar advances from MRI. A primary challenge has been replicating associations between inter-individual differences in brain structure or function and complex cognitive or mental health phenotypes (brain-wide association studies (BWAS)). Such BWAS have typically relied on sample sizes appropriate for classical brain mapping4 (the median neuroimaging study sample size is about 25), but potentially too small for capturing reproducible brain-behavioural phenotype associations5,6. Here we used three of the largest neuroimaging datasets currently available-with a total sample size of around 50,000 individuals-to quantify BWAS effect sizes and reproducibility as a function of sample size. BWAS associations were smaller than previously thought, resulting in statistically underpowered studies, inflated effect sizes and replication failures at typical sample sizes. As sample sizes grew into the thousands, replication rates began to improve and effect size inflation decreased. More robust BWAS effects were detected for functional MRI (versus structural), cognitive tests (versus mental health questionnaires) and multivariate methods (versus univariate). Smaller than expected brain-phenotype associations and variability across population subsamples can explain widespread BWAS replication failures. In contrast to non-BWAS approaches with larger effects (for example, lesions, interventions and within-person), BWAS reproducibility requires samples with thousands of individuals.

" Experimental and quasi-experimental designs for research on teaching ", de Donald T. Campbell & Julian C. Stanley, (1963).

Abstract: Il est de nombreuses problematiques qui ne peuvent pas etre explorees au moyen des methodes recommandees par Ronald Fischer en raison de leur nature ou des circonstances du terrain. Ceci n'est pas pour autant suffisant pour abandonner toute rigueur scientifique. C'est pourquoi dans un esprit fisherien, de nombreuses reflexions ont ete entreprises dans des domaines varies. Un des terrains les plus feconds a ete celui de la recherche dans le domaine de l'education comme l'illustre le dernier texte traduit dans cette partie qui est extrait d'un des chapitres d'un ouvrage sur ce sujet [11]. Ses auteurs, Julian C. Stanley (1918-2005) et Donald T. Campbell (1916-1996), sont des figures marquantes des sciences sociales americaines de la deuxieme moitie du xxe siecle. A la fin des annees 1960, Stanley a realise plusieurs recherches concernant les differences de performances scolaires selon le genre ou la race, recherches conduites sans craindre le reductionnisme ou le determinisme genetique de l'intelligence, ce qui lui a valu de faire l'objet d'assez vives critiques. Donald Campbell, lui, a ete forme initialement comme psychologue, mais fut connu d'abord en vertu de ses travaux methodologiques, mais aussi pour sa conception evolutionniste de l'epistemologie, de l'ethique et de l'anthropologie, et son positionnement fort en terme d'ethique academique, mefiante vis-a-vis des disciplines et favorisant l'heterodoxie theorique, la dissidence et le sens critique. Leur notoriete est probablement due au chapitre traduit ici qui a ete de nombreuses fois reedite (300 000 copies) et qui fait partie des textes parmi les plus cites dans le domaine des sciences sociales (plusieurs milliers de citations). Ce texte, fruit d'une collaboration relativement breve entre ces deux auteurs, est a replacer dans le mouvement reformateur qui, a la sortie de la seconde guerre mondiale, imposait aux programmes d'assistance sociale et aux politiques publiques l'utilisation de methodes leur permettant d'evaluer leur efficacite. On trouve trace a la fois d'une approche behavioriste parfois reductionniste et de cette ethique de l'impersonnalite, defendant la valeur morale d'une evaluation independante ecartant tout arbitraire. Ces methodologies vont se generaliser et ensuite se raffiner et le texte traduit ici represente un premier jalon dans la mise en place des methodes rationnelles d'evaluation qui ont aujourd'hui pris une place quasi-hegemonique dans les sciences humaines et sociales. Sont particulierement notables, outres les reflexions d'epistemologie sur la methode experimentale et l'induction, la conceptualisation des notions de biais et des notions correlatives de validite interne et externe. Dans ce texte apparait egalement l'idee selon laquelle la plus ou moins grande susceptibilite aux differentes sources de biais est une des caracteristiques des plans experimentaux et que par consequent la credibilite d'un resultat depend de la methodologie selon laquelle il a ete produit. Cette idee selon laquelle il y a des 'niveaux de preuve' deviendra structurante pour la pedagogie et l'analyse critique des resultats des differentes experiences menees notamment en medecine dans le cadre de la medecine appuyee sur des preuves (EBM).