The importance of thematic informativeness in narrative discourse recovery in acute post-stroke aphasia

Abstract

Background: Discourse analysis allows the examination of functional and ecological language impairment in post-stroke aphasia. Given its complexity, various methods of analysis have been developed to measure the multiple components of discourse. Clinical assessment usually includes discourse analysis, but how clinicians should assess recovery of discourse, particularly in acute care settings, is still a matter of debate. Aims: This study aimed to measure improvements in discourse production in early post-stroke aphasia recovery. Methods & Procedure: Twenty-three persons with aphasia following a first left middle cerebral artery stroke were recruited in the stroke unit of Hôpital du Sacré-Coeur de Montréal (May 2015-July 2018). Patients treated with thrombolysis (n=10) and untreated patients underwent two aphasia assessments (0 to 72 hours, 7 to 14 days post-onset). Discourse assessment consisted of the picture description task from the Western Aphasia Battery (Kertesz, 2006). Changes in microlinguistic and thematic informativeness measures between the two assessment periods were analyzed. Outcomes & Results: In-depth microlinguistic analyses showed no significant difference between the initial and follow-up assessments. Conversely, some thematic informativeness variables improved significantly during the same time period. Patients treated with thrombolysis produced more thematic units than untreated patients at both assessments, but the change between the two groups was not significant. Conclusions & Implications: This study suggests that thematic informativeness variables are sensitive to language improvement in early post-stroke aphasia recovery whereas no microlinguistic variables improved significantly in the same period. In contrast to previous evidence, the difference between patients treated with thrombolysis and untreated patients was not evident over time. The results suggest that thematic informativeness constitutes an interesting path to explore as NARRATIVE DISCOURSE RECOVERY Aphasiology (accepted) 4 a routine clinical assessment in acute-care settings because it is time-efficient, simple to conduct and reliable in assessing early changes in the discourse production of individuals with aphasia in the acute post-stroke phase.

A longitudinal study of narrative discourse in post-stroke aphasia

“…Despite the growing importance of spoken discourse analysis in post-stroke aphasia, little is known about the longitudinal changes on these microstructural measures. Previous findings suggest that they do not evolve as much as expected in the acute and sub-acute phases of recovery (Brisebois et al, 2020), or even when language therapy is provided (Carlomagno et al, 2001;Larfeuil & Le Dorze, 1997;Marini et al, 2007).…”

“…For instance, impairments in informativeness have been reported in severe aphasia (e.g., Ulatowska et al, 1983), whereas other studies identified no such impairment in people with mild or moderate aphasia (e.g., Yorkston & Beukelman, 1980). However, recent research (e.g., Alyahya et al, 2020;Brisebois et al, 2020) has demonstrated that informativeness impairment affects PWA with various language impairment severities in acute, subacute and chronic stages of recovery.…”

“…This type of analysis is particularly appropriate to assess discourse performance on a picture description task since the performance on such a task relies primarily on the patient's abilities to interpret the stimulus and formulate a message representing that stimulus (Kong, 2016). This type of analysis has also been of particular interest because a determined set of information units allows for an easier comparison of the discourse performance between people with chronic aphasia and healthy speakers (Dalton & Richardson, 2015) and within groups of people with aphasia over time (Brisebois et al, 2020).…”

“…Our team also recently reported on the early changes in informativeness in the picture description of the Western Aphasia Battery Revised (Kertesz, 2006) in a group of 23 PWA with different types of aphasia and severity (i.e., ranging from mild to severe) (Brisebois et al, 2020). We calculated informativeness in terms of macro-structural units which consisted of a specific list of thematic units previously identified based on the production of healthy speakers (as described in .…”

“…The main goal of the present study is, thus, to measure changes in spoken production of French-Canadian speaking individuals with post-stroke aphasia using the picture description task of the WAB-R (Kertesz, 2006) To do so, micro-structural variables that have been reported to be sensitive to language impairment (namely number of words per minute and mean length of utterance) Andreetta & Marini, 2015;Fergadiotis & Wright, 2015;Fromm et al, 2016) were collected to document in-depth linguistic aspects of discourse production. Thematic informativeness variables (Brisebois et al, 2020) were also collected as they refer to broader discourse metrics that represent semantic content and linguistic form but are also are easy to implement in clinical settings and can be scored rapidly. Based on previous longitudinal studies, (e.g., Furlanis et al, 2018), and also on the fact that language recovery continues for a long period after stroke (Bernhardt et al, 2017;Pedersen et al, 2004), we expect positive changes over the course of time.…”