The longitudinal trajectory of discourse from the hyperacute to the chronic phase in mild to moderate poststroke aphasia recovery: A case series study.

BACKGROUND: Discourse analysis has recently received much attention in the aphasia literature. Even if post-stroke language recovery occurs throughout the longitudinal continuum of recovery, very few studies have documented discourse changes from the hyperacute to the chronic phases of recovery. AIMS: To document a multilevel analysis of discourse changes from the hyperacute phase to the chronic phase of post-stroke recovery using a series of single cases study designs. METHODS & PROCEDURES: Four people with mild to moderate post-stroke aphasia underwent four assessments (hyperacute: 0-24 h; acute: 24-72 h; subacute: 7-14 days; and chronic: 6-12 months post-onset). Three discourse tasks were performed at each time point: a picture description, a personal narrative and a story retelling. Multilevel changes in terms of macro- and microstructural aspects were analysed. The results of each discourse task were combined for each time point. Individual effect sizes were computed to evaluate the relative strength of changes in an early and a late recovery time frame. OUTCOMES & RESULTS: Macrostructural results revealed improvements throughout the recovery continuum in terms of coherence and thematic efficiency. Also, the microstructural results demonstrated linguistic output improvement for three out of four participants. Namely, lexical diversity and the number of correct information units/min showed a greater gain in the early compared with the late recovery phase. CONCLUSIONS & IMPLICATIONS: This study highlights the importance of investigating all discourse processing levels as the longitudinal changes in discourse operate differently at each phase of recovery. Overall results support future longitudinal discourse investigation in people with post-stroke aphasia. WHAT THIS PAPER ADDS: What is already known on the subject Multi-level discourse analysis allows for in-depth analysis of underlying discourse processes. To date, very little is known on the longitudinal discourse changes from aphasia onset through to the chronic stage of recovery. This study documents multi-level discourse features in four people with mild to moderate aphasia in the hyperacute, acute, subacute and chronic stage of post-stroke aphasia recovery. What this paper adds to existing knowledge The study found that most discourse variables demonstrated improvement throughout time. Macrostructural variables of coherence and thematic units improved throughout the continuum whereas microstructural variables demonstrated greater gains in the early compared to the late period of recovery. What are the potential or actual clinical implications of this work? This study suggests that multilevel discourse analysis will allow a better understanding of post-stroke aphasia recovery, although more research is needed to determine the clinical utility of these findings. Future research may wish to investigate longitudinal discourse recovery in a larger sample of people with aphasia with heterogenous aphasia profiles and severities.

Neuroanatomical correlates of macrostructural receptive abilities in narrative discourse in unilateral left hemisphere stroke: A behavioural and voxel-based morphometry study.

BACKGROUND: Little is known about story retelling and comprehension abilities in groups with lower levels of education and socio-economic status (SES). A growing body of evidence suggests the role of an extended network supporting narrative comprehension, but few studies have been conducted in clinical populations, even less in developing countries. AIMS: To extend our knowledge of the impact of a stroke on macrostructural aspects of discourse processes, namely main and complementary information, in individuals with middle-low to low SES and low levels of education. Relationships were tested between the performance in story retell and comprehension and reading and writing habits (RWH). Also, the associations between retelling and comprehension measures and their structural grey matter (GM) correlates were explored. METHODS & PROCEDURES: A total of 17 adults with unilateral left hemisphere (LH) chronic ischaemic stroke without the presence of significant aphasia and 10 matched (age, education and SES) healthy controls (HC) participated in the study. Retell and comprehension tasks were performed after listening or reading narrative stories. Voxel-based morphometry (VBM) analysis was conducted on a subgroup of nine individuals with LH stroke and the 10 matched controls using structural magnetic resonance imaging (MRI). OUTCOMES & RESULTS: Retelling and comprehension abilities were not significantly different between LH and HC, nonetheless quantitively lower in LH. Exploratory correlations showed that retelling and comprehension abilities in both written and auditory modalities were correlated with naming abilities. At the neural level, written comprehension positively correlated with GM density of the LH, including areas in the temporal pole, superior and middle temporal gyrus as well as the orbitofrontal cortex, precentral and postcentral gyri. Auditory narrative comprehension was associated with GM density of the lingual gyrus in the right hemisphere. CONCLUSIONS & IMPLICATIONS: The present results suggest that retelling and comprehension of auditory and written narratives are relatively well-preserved in individuals with a LH stroke without significant aphasia, but poorer than in HC. The findings replicate previous studies conducted in groups with higher levels of education and SES both at the behavioural and neural levels. Considering that naming seems to be associated with narrative retell and comprehension in individuals with lower SES and education, this research provides evidence on the importance of pursuing further studies including larger samples with and without aphasia as well as with various SES and education levels. WHAT THIS PAPER ADDS: What is already known on this subject Story retell and comprehension of auditory and written discourse have been shown to be affected after stroke, but most studies have been conducted on individuals with middle to high SES and high educational levels. What this paper adds to existing knowledge The study reports on narrative retell and comprehension in both auditory and written modalities in groups of HC and individuals with LH brain damage, with low-to-middle SES and lower levels of education. What are the potential or actual clinical implications of this work? This study highlights the importance of taking into consideration the sociodemographic and RWH of patients when assessing discourse retell and comprehension in both auditory and written modalities. It also underlines the importance of including patients without significant aphasia following LH stroke to look at the effect of both stroke and aphasia on narrative comprehension and story retelling.

Reliability of the picture description task of the Western Aphasia Battery - revised in Laurentian French persons without brain injury.

Objective: Limited normative data (including psychometric properties) are currently available on discourse tasks in non-dominant languages such as Laurentian (Quebec) French. The lack of linguistic and cultural adaptation has been identified as a barrier to discourse assessment. The main aim of this study is to document inter-rater and test-retest reliability properties of the picnic scene of the Western Aphasia Battery - Revised (WAB-R), including the cultural adaptation of an information content unit (ICU) list, and provide a normative reference for persons without brain injury (PWBI). Method: To do so, we also aimed to adapt an ICU checklist culturally and linguistically for Laurentian French speakers. Discourse samples were collected from 66 PWBI using the picture description task of the WAB-R. The ICU list was first adapted into Laurentian French. Then, ICUs and thematic units (TUs) were extracted manually, and microstructural variables were extracted using CLAN. Inter-rater reliability and test-retest reliability were determined. Results: Excellent inter-rater reliability was obtained for ICUs and TUs, as well as for all microstructural variables, except for mean length of utterance, which was found to be good. Conversely, test-retest reliability ranged from poor to moderate for all variables. Conclusion: The present study provides a validated ICU checklist for clinicians and researchers working with Laurentian French speakers when assessing discourse with the picnic scene of the WAB-R. It also addresses the gap in available psychometric data regarding inter-rater and test-retest reliability in PWBI.

Adaptation and Reliability of the Cinderella Story Retell Task in Canadian French Persons Without Brain Injury.

PURPOSE: Main concept (MC) analysis is a well-documented method of discourse analysis in adults with and without brain injury. This study aims to develop a MC checklist that is culturally and linguistically adapted for Canadian French speakers and examine its reliability. We also documented microstructural properties and provide a normative reference in persons not brain injured (PNBIs). METHOD: Discourse samples from 43 PNBIs were collected. All participants completed the Cinderella story retell task twice. Manual transcription was performed for all samples. The 34 MCs for the Cinderella story retell task were adapted into Canadian French and used to score all transcripts. In addition, microstructural variables were extracted using Computerized Language Analysis (CLAN). Intraclass correlation coefficients were computed to assess interrater reliability for MC codes and microstructural variables. Test-retest reliability was assessed using intraclass correlations, Spearman's rho correlations, and the Wilcoxon signed-ranks test. Bland-Altman plots were used to examine the agreement of the discourse measures between the two sessions. RESULTS: The MC checklist for the Cinderella story retell task adapted for Canadian French speakers is provided. Good-to-excellent interrater reliability was obtained for most MC codes; however, reliability ranged from poor to excellent for the "inaccurate and incomplete" code. Microstructural variables demonstrated excellent interrater reliability. Test-retest reliability ranged from poor to excellent for all variables, with the majority falling between moderate and excellent. Bland-Altman plots illustrated the limits of agreement between test and retest. CONCLUSIONS: This study provides the MC checklist for clinicians and researchers working with Canadian French speakers when assessing discourse with the Cinderella story retell task. It also addresses the gap in available psychometric data regarding test-retest reliability in PNBIs. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.24171087.

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.

Validation of Videoconference Administration of Picture Description From the Western Aphasia Battery-Revised in Neurotypical Canadian French Speakers.

PURPOSE: During the COVID-19 pandemic, clinicians and researchers have increasingly used remote online assessments to pursue their activities, but mostly with tests not validated for videoconference administration. This study aims to validate the remote online administration of picture description in Canadian French neurotypical speakers and to explore the thematic unit (TU) checklist recently developed. METHOD: Spoken discourse elicited through the picture description task of the Western Aphasia Battery-Revised (WAB-R) was collected from Canadian French neurotypical speakers from Québec aged between 50 and 79 years old. Forty-seven participants completed the task in person, and 49 participants completed the task by videoconference. Videos of each discourse sample were transcribed using CHAT conventions. Microstructural variables were extracted using the CLAN (Computerized Language ANalysis) program, whereas thematic informativeness was scored for each sample using TUs. Chi-square tests were conducted to compare both groups on each TU; t tests were also performed on the total score of TUs and microstructural variables. RESULTS: Groups were matched on sex, age, and education variables. The t tests revealed no intergroup difference for the total TU score and for the microstructural variables (e.g., mean length of utterances and number of words per minute). Chi-square tests showed no significant intergroup difference for all 16 TUs. CONCLUSIONS: These findings support remote online assessment of the picnic scene of the WAB-R picture description in Canadian French neurotypical speakers. These results also validate the 16 TUs most consistently produced. The use of videoconference could promote and improve the recruitment of participants who are usually less accessible, such as people using assistive mobility technologies. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21476961.

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.

Macrostructural Aspects in Oral Narratives in Brazilian Portuguese by Left and Right Hemisphere Stroke Patients With Low Education and Low Socioeconomic Status.

OBJECTIVE: Individuals with a stroke in either the left hemisphere (LH) or the right hemisphere (RH) often present macrostructural impairments in narrative abilities. Understanding the potential influence of low education and low socioeconomic status (SES) is critical to a more effective assessment of poststroke language. The first aim was to investigate macrostructural processing in low-education and low-SES individuals with stroke in the LH or RH or without brain damage. The second aim was to verify the relationships between macrolinguistic, neuropsychological, and sociodemographic variables. METHOD: Forty-seven adults with LH (n = 15) or RH (n = 16) chronic ischemic stroke and 16 matched (age, education, and SES) healthy controls produced three oral picture-sequence narratives. The macrostructural aspects analyzed were cohesion, coherence, narrativity, macropropositions, and index of lexical informativeness and were compared among the three groups. Then, exploratory correlations were performed to assess associations between sociodemographic (such as SES), neuropsychological, and macrostructural variables. RESULTS: Both the LH and the RH presented impairments in the local macrostructural aspect (cohesion), whereas the RH also presented impairments in more global aspects (global coherence and macropropositions). All five macrostructural variables correlated with each other, with higher correlations with narrativity. Naming was correlated with all macrostructural variables, as well as prestroke reading and writing habits (RWH), showing that higher naming accuracy and higher RWH are associated with better macrostructural skills. CONCLUSIONS: The present results corroborate the role of the LH in more local processing and that of the RH in more global aspects of discourse. Moreover, this study highlights the importance of investigating discourse processing in healthy and clinical populations of understudied languages such as Brazilian Portuguese, with various levels of education, SES, and RWH.

Neuroanatomical Correlates of Macrolinguistic Aspects in Narrative Discourse in Unilateral Left and Right Hemisphere Stroke: A Voxel-Based Morphometry Study.

Background A growing body of literature has demonstrated the importance of discourse assessment in patients who suffered from brain injury, both in the left and right hemispheres, as discourse represents a key component of functional communication. However, little is known about the relationship between gray matter density and macrolinguistic processing. Purpose This study aimed to investigate this relationship in a group of participants with middle-low to low socioeconomic status. Method Twenty adults with unilateral left hemisphere (n = 10) or right hemisphere (n = 10) chronic ischemic stroke and 10 matched (age, education, and socioeconomic status) healthy controls produced three oral narratives based on sequential scenes. Voxel-based morphometry analysis was conducted using structural magnetic resonance imaging. Results Compared to healthy controls, the left hemisphere group showed cohesion impairments, whereas the right hemisphere group showed impairments in coherence and in producing macropropositions. Cohesion positively correlated with gray matter density in the right primary sensory area (PSA)/precentral gyrus and the pars opercularis. Coherence, narrativity, and index of lexical informativeness were positively associated with the left PSA/insula and the superior temporal gyrus. Macropropositions were mostly related to the left PSA/insula and superior temporal gyrus, left cingulate, and right primary motor area/insula. Discussion Overall, the present results suggest that both hemispheres are implicated in macrolinguistic processes in narrative discourse. Further studies including larger samples and with various socioeconomic status should be conducted. Supplemental Material https://doi.org/10.23641/asha.14347550.

Predicting Early Post-stroke Aphasia Outcome From Initial Aphasia Severity.

Background: The greatest degree of language recovery in post-stroke aphasia takes place within the first weeks. Aphasia severity and lesion measures have been shown to be good predictors of long-term outcomes. However, little is known about their implications in early spontaneous recovery. The present study sought to determine which factors better predict early language outcomes in individuals with post-stroke aphasia. Methods: Twenty individuals with post-stroke aphasia were assessed <72 h (acute) and 10-14 days (subacute) after stroke onset. We developed a composite score (CS) consisting of several linguistic sub-tests: repetition, oral comprehension and naming. Lesion volume, lesion load and diffusion measures [fractional anisotropy (FA) and axial diffusivity (AD)] from both arcuate fasciculi (AF) were also extracted using MRI scans performed at the same time points. A series of regression analyses were performed to predict the CS at the second assessment. Results: Among the diffusion measures, only FA from right AF was found to be a significant predictor of early subacute aphasia outcome. However, when combined in two hierarchical models with FA, age and either lesion load or lesion size, the initial aphasia severity was found to account for most of the variance (R 2 = 0.678), similarly to the complete models (R 2 = 0.703 and R 2 = 0.73, respectively). Conclusions: Initial aphasia severity was the best predictor of early post-stroke aphasia outcome, whereas lesion measures, though highly correlated, show less influence on the prediction model. We suggest that factors predicting early recovery may differ from those involved in long-term recovery.