Longitudinal evolution of diffusion metrics after left hemisphere ischaemic stroke.

White matter is often severely affected after human ischaemic stroke. While animal studies have suggested that various factors may contribute to white matter structural damage after ischaemic stroke, the characterization of damaging processes to the affected hemisphere after human stroke remains poorly understood. Thus, the present study aims to thoroughly describe the longitudinal pattern of evolution of diffusion magnetic resonance imaging metrics in different parts of the ipsilesional white matter after stroke. We acquired diffusion and anatomical images in 17 patients who had suffered from a single left hemisphere ischaemic stroke, at 24-72 h, 8-14 days and 6 months post-stroke. For each patient, we created three regions of interest: (i) the white matter lesion; (ii) the perilesional white matter; and (iii) the remaining white matter of the left hemisphere. We extracted diffusion metrics (fractional anisotropy, mean, axial and radial diffusivities) for each region and conducted two-way repeated measures ANOVAs with stage post-stroke (acute, subacute and chronic) × regions of interest (white matter lesion, perilesional white matter and remaining white matter). Fractional anisotropy values stayed consistent across time-points, with significantly lower values in the white matter lesion compared to the perilesional white matter and remaining white matter tissue. Fractional anisotropy values of the perilesional white matter were also significantly lower than that of the remaining white matter. Mean, axial and radial diffusivities in the white matter lesion were all decreased in the acute stage compared to perilesional white matter and remaining white matter, but significantly increased in both the subacute and chronic stages. Significant increases in mean and radial diffusivities in the perilesional white matter were seen in the later stages of stroke. Our findings suggest that various physiological processes are at play in the acute, subacute and chronic stages following ischaemic stroke, with the infarct territory and perilesional white matter affected by ischaemia at different rates and to different extents throughout the stroke recovery stages. The examination of multiple diffusivity metrics may inform us about the mechanisms occurring at different time-points, i.e. focal swelling, axonal damage or myelin loss.

Picture Description of the Western Aphasia Battery Picnic Scene: Reference Data for the French Canadian Population.

PURPOSE: The main aim of this study is to provide French Canadian reference data for quantitative measures extracted from connected speech samples elicited by the Western Aphasia Battery-Revised picnic scene, a discourse task frequently used in clinical assessment of acquired language disorders. METHOD: Our sample consisted of 62 healthy French Canadian adults divided in two age groups: a 50- to 69-year-old group and a 70- to 90-year-old group. RESULTS: High interrater reliability scores were obtained for most of the variables. Most connected speech variables did not demonstrate an age effect. However, the 70- to 90-year-old group produced more repetitions than the 50- to 69-year-old group and displayed reduced communication efficiency (number of information content units per minute). CONCLUSION: These findings contribute to building a reference data set to analyze descriptive discourse production in clinical settings.

Word-finding in confrontation naming and picture descriptions produced by individuals with early post-stroke aphasia.

Objective: The present study aims to assess the relationship between quantitative measures of connected speech production and performance in confrontation naming in early post-stroke aphasia (8-14 days post-stroke). Method: We collected connected speech samples elicited by a picture description task and administered a confrontation naming task to 20 individuals with early post-stroke aphasia and 20 healthy controls. Transcriptions were made in compliance with the CHAT format guidelines. Several micro- (i.e. duration, total number of words, words per minute, mean length of utterances, ratio of open- to closed-class words and noun-to-verb ratio, VOC-D, repetitions, self-corrections, and phonological and semantic errors) and macrolinguistic (i.e. informativeness and efficiency) measures were extracted. Results: We provide evidence for the presence of impairments in an array of micro- and macrolinguistic measures of speech in individuals with early post-stroke aphasia. We show that in the patient group, confrontation naming abilities most strongly relate to informativeness in a picture description task. Conclusion: Our findings contribute to a better understanding of the relationship between performance in confrontation naming and in connected speech production in the first days after stroke onset and also suggest that discourse analysis may provide unique, possibly more complex information.

Predicting and preventing symptom onset and relapse in schizophrenia-A metareview of current empirical evidence.

The stress-vulnerability-protective factors model is often used to explain the etiology and known risk and protective factors of initial psychotic symptoms and symptomatic relapses. Over the past 40 years since its initial conception, the model has evolved and gathered a plethora of evidence of varying quality for its different components. The objective of this metareview is to analyze the quality of the evidence and the effect sizes for each component of the model not previously reviewed. Recent meta-analyses covering each component of the model in relation to the onset of psychotic symptoms or symptomatic relapse in schizophrenia were reviewed with the grading of recommendations, assessment, development, and evaluation system. Thirty-one meta-analyses were kept, from 3,044 papers reviewed. We did not add to previous metareviews in terms of obstetric/prenatal or genetic vulnerabilities. For stressors, moderate to strong research evidence was found for childhood adversity, cannabis, methamphetamine abuse, and expressed emotions as triggers of psychotic relapse or as linked to the onset of psychotic symptoms. For protective factors, moderate to strong evidence was found for antipsychotic medication in adults, family interventions, social skills training, as well as interventions focusing on recovery management skills. Poor evidence or no evidence (i.e., absence of meta-analyses) were found for the other components of the model. More rigorous studies and systematic reviews are needed in order to validate the various components of the model in regard to symptom onset and relapse. (PsycINFO Database Record (c) 2019 APA, all rights reserved).