Verbal and nonverbal cognitive control functions in post-stroke nonfluent aphasia

ABSTRACTBackground: Although studies show that different facets of cognitive control are impaired in persons with aphasia (PWA), the question how they impact language abilities in different types of aphasia remains open.Aims: Following the hypothesis that diminished attention contributes to language impairments in aphasia, we predicted that both fluent and non-fluent PWA would perform worse than neurologically intact individuals on verbal and non-verbal cognitive control tasks. Also, testing the view that linguistic disturbances in fluent and non-fluent PWA dissociate, we predicted differential relationships in performance on cognitive control tasks and language impairment.Methods & Procedures: Fluent PWA (N = 17) and non-fluent PWA (N = 14) were compared to unimpaired speakers (N = 21) on the non-verbal Flanker task tapping domain-general cognitive control, and Stroop task measuring verbal cognitive control, as well as subtests from the Russian version of the Birmingham Cognitive Screen, namely the Auditory Control task tapping verbal cognitive control and the Rule Finding task measuring domain-general cognitive control. All PWA completed picture naming and language comprehension tasks.Outcomes & Results: All PWA were more impaired on the Stroop and Auditory Control tasks, with no impairment on the non-verbal Flanker task compared to the controls. Non-fluent PWA also performed significantly worse on the Rule Finding that requires forming and updating non-verbal relational representations. Differences between aphasia groups were found on the Auditory Control task only, where non-fluent PWA were more vulnerable to task demands. Correlation analyses found that verbal and non-verbal cognitive control performance was correlated for the non-fluent group, whereas only correlations between verbal cognitive control tasks were significant for the fluent group. For all PWA, non-verbal cognitive control indexed by Flanker interference scores was related to language comprehension, whereas verbal cognitive control was related to picture naming. However, non-verbal relational reasoning as indexed by the Rule Finding task was significantly related to language comprehension in the non-fluent group only.Conclusions: All PWA had diminished verbal cognitive control. Non-fluent PWA demonstrated higher vulnerability to domain-general cognitive control deficits compared to fluent PWA. Performance on verbal and non-verbal cognitive control tasks significantly overlapped in the non-fluent group only. Both groups recruited non-verbal cognitive control during language comprehension and verbal cognitive control during picture naming. Only non-fluent PWA relied on domain-general relational reasoning during language comprehension. These findings reinforce the importance of cognitive assessment in aphasia.

Cognitive control in older Minnan-Mandarin and Hakka-Mandarin bidialectal adults: Advantages in Stroop-type tasks

Background: Recent studies imply that executive functions (EF) are closely related to our ability to comprehend and produce language. A number of findings suggest that functional communication and language recovery in aphasia depend not only on intact language abilities but on EF as well. Some patients with transcortical motor aphasia (TMA) show language deficits only in tasks in which conflicting representations must be resolved by executive processes. In line with these results, others have proposed that TMA should be referred to as “dysexecutive aphasia”. EF in aphasia have mostly been studied using neuropsychological tests, therefore there is a need for systematic experimental investigations of these skills.Aims: 1. To investigate EF in TMA, and to test whether executive dysfunctions are specific to TMA. 2. To experimentally measure different components of EF: updating working memory representations and inhibition of prepotent responses.Methods & Procedures: Five individuals with TMA, five patients with conduction aphasia and ten healthy controls participated. We designed four nonverbal tasks: to measure updating of working memory representations, we used a visual and an auditory n-back task. To assess inhibition of prepotent responses, we designed a Stop-signal and a nonverbal Stroop task. All tasks involved within-subject baseline conditions.Outcomes & Results: We found certain EF deficits in both groups of individuals with aphasia as compared to healthy controls. Individuals with TMA showed impaired inhibition as indexed by the Stop-signal and the nonverbal Stroop tasks, as well as a deficit of updating of working memory representations as indexed by the auditory n-back task. Participants with conduction aphasia had difficulties in only one of the tasks measuring inhibition, but no clear evidence for impairment of updating of working memory representations was found.Conclusions: Although the results show different patterns of EF deficits in the groups with aphasia, the findings clearly demonstrate that EF deficits are not specific to participants with TMA. Based on these results, and on earlier data highlighting the role of executive processes in functional communication and language recovery, we suggest that tests of EF should be an inherent part of clinical aphasia assessment.

Cognitive control refers to the ability to perform goal-directed behaviors in the presence of other compelling actions or in the face of habitual practices. Cognitive control functions play a critical role in children's language processing and literacy development. In recent years, many clinicians have expanded their assessment and treatment to target specific cognitive skills. Our goal is to provide a review of recent findings on cognitive control functions in children with different language status (i.e., monolingual and bilingual children with and without language impairment). While children with language impairment show performance deficits in specific cognitive functions (e.g., working memory updating and interference control), typically developing bilingual children often outperform their monolingual peers in cognitive control tasks. However, the relationship between bilingualism and cognitive control has been controversial. Several factors that influence these variations are discussed. Given the findings on the joint impact of bilingualism and language impairment on cognitive control functions, we identify conditions in which bilingualism attenuates the negative effects of the language deficit and conditions in which language impairment has a stronger effect than bilingualism. Critical issues of bilingual assessment, suggestions, and future directions are discussed.

Event Abstract Back to Event A comparison of processing load during non-verbal decision-making in two individuals with aphasia Salima Suleman1*, Esther S. Kim1 and Tammy Hopper1 1 University of Alberta, Canada INTRODUCTION A growing body of evidence suggests people with aphasia (PWA) can have impairments to cognitive functions such as attention, working memory and executive functions.(1-5) Such cognitive impairments have been shown to negatively affect the decision-making (DM) abilities adults with neurological damage. (6,7) However, little is known about DM abilities of PWA.(8) Pupillometry is “the measurement of changes in pupil diameter”.(9;p.1) Researchers have reported a positive relationship between processing load and phasic pupil size (i.e., as processing load increases, pupil size increases).(10) Thus pupillometry has the potential to be a useful tool for investigating processing load during DM in PWA. AIMS The primary aim of this study was to establish the feasibility of using pupillometry during a non-verbal DM task with PWA. The secondary aim was to explore non-verbal DM performance in PWA and determine the relationship between DM performance and processing load using pupillometry. METHOD DESIGN. A single-subject case-study design with two participants was used in this study. PARTICIPANTS. Two adult males with anomic aphasia participated in this study. Participants were matched for age and education. Both participants were independent, able to drive, and had legal autonomy. MEASURES. PERFORMANCE ON A DM TASK. We used a computerized risk-taking card game called the Iowa Gambling Task (IGT) as our non-verbal DM task.(11) In the IGT, participants made 100 selections (via eye gaze) from four decks of cards presented on the computer screen with the goal of maximizing their overall hypothetical monetary gain. PROCESSING LOAD. The EyeLink 1000+ eye tracking system was used to collect pupil size measures while participants deliberated before each deck selection during the IGT. For this analysis, we calculated change in pupil size as a measure of processing load. RESULTS P1. P1 made increasingly advantageous decisions as the task progressed (Fig.1). When asked to rank order the decks, P1 consistently identified the advantageous decks as the best decks after block two. We found a significant negative non-parametric correlation between trial and change in pupil size (rs = - 0.481, n = 100, p < 0.0001). P2. P2 made increasingly disadvantageous decisions as the task progressed (Fig. 1). When asked to rank the decks, P2 was unable to accurately and consistently identify advantageous decks at the end of the task. At the end of block five, P2 stated “I didn’t have the sense of ‘that was going to be the good one’”. We found a significant negative correlation between change in pupil size and trial number (rs = - 0.379, n = 100, p < 0.0001). DISCUSSION Two participants with similar aphasia demonstrated disparate DM performance. P1 quickly determined the way to maximize his gain, while P2 was unable to discern the best way to maximize his gain and made more disadvantageous decisions as the task progressed. Both participants showed decreasing changes in pupil size related to processing load. These results demonstrate the feasibility of using pupillometry in a computerized DM task with PWA. Further, we know that even when language profiles are similar, DM abilities may be differentially affected in aphasia. These preliminary data will be used to inform a subsequent, larger study of DM in PWA. Figure 1 References

Assessing spoken discourse during aphasia clinical examination is crucial for diagnostic and rehabilitation purposes. Recent approaches have been developed to quantify content word fluency (CWF) and informativeness of spoken discourse without the need to perform time-consuming transcription and coding. However, the accuracy of these approaches has not been examined in real-time clinical settings, and they have been developed and validated mainly in English and thus cannot be applied to other languages. For the first time: (i) to create and validate CWF checklists and main concept (MC) lists in Arabic; (ii) to examine the application of these two approaches in real-time clinical settings with people with aphasia (PWA) while they are performing the task; and (iii) to investigate whether these two approaches can differentiate discourse responses produced by PWA versus neurotypical adults. The Arabic Discourse Assessment Tool (ADAT) was used to collect discourse responses on three tasks (composite picture description, storytelling narrative, and procedural discourse) from 70 neurotypical control adults and 50 PWA matched to the control group in age and education. The discourse samples were transcribed, and analysed. For each task, CWF checklists and MC lists were developed and validated using discourse reponses from the control group. Afterwards, the application of these two approaches in real-time clinical settings was examined with the aphasia groups. The psychometric properties of CWF and MC approches were examined. Novel Arabic CWF checklists and MC lists were successfully developed, validated, and applied clinically for three discourse tasks. The analysis showed significant high accuracy between CWF scores obtained in real-time clinical settings and those identified using the traditional approach of transcribing and analysing discourse samples across all three discourse tasks (ICC = 0.88 to 0.94). Furthermore, significant excellent reliability (ICC = 0.917 to 0.994) were found for the three tasks in both groups. Most of the MCs were produced accurately and completely by neurotypical control adults, whereas they were mostly absent in PWA. CWF checklists and MC lists showed significant high validity in distinguishing spoken discourse produced by PWA from those produced by neurotypical adults at p < 0.001. This is the first study to develop and validate novel Arabic CWF checklists and MC lists. Furthermore, this study demonstrated that the CWF approach and main concept analysis (MCA) can be applied clinically in real-time with PWA. These transcription-less approaches can be used as part of the routine aphasia clinical examination to provide quick but accurate assessments of CWF (microlinguistics) and informativeness (macrolinguistics) of spoken discourse in PWA. These approaches also provide a significant resource for Arabic speakers with aphasia, that will lead to accurate aphasia assessments and better clinical management. What is already known on the subject Conversations between people rely heavily on producing relevant and informative spoken discourse. Thus, there has been increased interest in the application of discourse tasks in clinical practice to enable a comprehensive assessment of expressive language and functional communication. However, utilising discourse tasks in clinical settings is impractical because their administration and scoring are time-consuming, labour-heavy, and must be completed after the session has ended. Therefore, transcription-less, efficient, and accurate approaches to analyse discourse responses have been developed and validated in English. However, no study has investigated the application of these approaches in real-time clinical settings with people with aphasia (PWA). What this study adds To our knowledge, this is the first study to (i) develop and validate content word fluency (CWF) checklists and main concept (MC) lists in Arabic. These were created for three discourse tasks (composite picture description, storytelling narratives, and procedural discourse) using discourse responses from a neurotypical control group; and (ii) examine the application of these valid, transcription-less, efficient, and accurate approaches to assess CWF and informativeness of spoken discourse in PWA in real-time clinical settings. What are the potential or actual clinical implications of this work? The transcription-less, efficient, and accurate discourse assessment approaches that have been developed and validated in this study allow clinicians to objectively assess discourse responses produced by Arabic speakers with aphasia during clinical examinations while the person is speaking without the need for offline transcription, analyses, and scoring. The reliable application of these approaches in real-time clinical settings encourages clinicians to incorporate discourse tasks as part of their routine clinical examination with PWA to be used (i) for a comprehensive assessment of expressive language skills beyond words and sentences, (ii) to guide the development of personalised therapy goals and strategies to improve functional communication, and (iii) as outcome measurements to monitor spontaneous recovery and changes in response to interventions.

Bilingual children often exhibit superior speed of processing compared to monolingual peers in cognitive control tasks (e.g., Bialystok, 2010). In this chapter, we focus on the interactions among processing speed, cognitive control, age, and bilingualism. Individual differences in speed of processing reflect variation in participants’ skills and in task complexity. The more complex a task, the more cognitive control is involved (Cepeda, Blackwell, &amp; Munakata, 2013). Age also interacts with speed of processing and cognitive control; the same speed of processing task may require more and/or different cognitive control processes at different ages. Furthermore, in bilingual children, speed of processing and cognitive control are associated with different components of their bilingual experience, such as language proficiency and age of acquisition. The cognitive control account (Cohen, 2017) provides a useful framework for studying information processing in bilingual children because it emphasizes the flexibility and adaptation of the cognitive system in response to changing contexts.

In the present preregistered study, we evaluated the possibility of a shared cognitive mechanism during verbal and non-verbal tasks and therefore the implication of domain-general cognitive control during language comprehension. We hypothesized that a behavioral cost will be observed during a dual-task including both verbal and non-verbal difficult processing. Specifically, to test this claim, we designed a dual-task paradigm involving: an auditory language comprehension task (sentence comprehension) and a non-verbal Flanker task (including congruent and incongruent trials). We manipulated sentence ambiguity and evaluated if the ambiguity effect modified behavioral performances in the non-verbal Flanker task. Under the assumption that ambiguous sentences induce a more difficult process than unambiguous sentences, we expected non-verbal flanker task performances to be impaired only when a simultaneous difficult language processing is performed. This would be specifically reflected by a performance cost during incongruent Flanker items only during ambiguous sentence presentation. Conversely, we observed a facilitatory effect for the incongruent Flanker items during ambiguous sentence suggesting better non-verbal inhibitory performances when an ambiguous sentence was simultaneously processed. Exploratory data analysis suggests that this effect is not only related to a more difficult language processing but also to the previous (n-1) Flanker item. Indeed, results showed that incongruent n-1 Flanker items led to a facilitation of the incongruent synchronized Flanker items only when ambiguous sentences were conjointly presented. This result, even if it needs to be corroborated in future studies, suggests that the recruitment of executive control mechanisms facilitates subsequent executive control implication during difficult language processing. The present study suggests a common executive control mechanism during difficult verbal and non-verbal tasks.

Background Prosody is essential for effective communication, serving both linguistic and non-linguistic functions. While prosodic processing is thought to be lateralized in the brain based on functions, domains, and acoustic cues, lesion studies have produced heterogeneous results. A quantitative synthesis of existing research on prosodic perception in people with aphasia (PWA) is needed to clarify the severity and patterns of prosodic impairments linked to left-hemisphere damage. Aims This meta-analysis examines prosodic perception in PWA in comparison with neurotypical individuals across different prosodic functions (linguistic and emotional), domains (word, sentence, and discourse), and cues (spectral and temporal). Methods & Procedures We conducted a systematic literature search across three electronic databases, focusing on studies that compared prosodic perception in PWA to that of neurotypical controls with accuracy and/or response times measures. A multi-level meta-analysis was performed to estimate both the overall severity and specific patterns of prosodic impairment in PWA. Meta-regression analyses were conducted to identify potential moderating factors related to participant characteristics and experimental design. Outcomes & Results Sixty-two studies assessed prosodic perception in PWA (n = 446) compared to neurotypical controls (n = 518). The meta-analysis revealed that PWA exhibited significantly lower accuracy and longer response times across all prosodic functions and cues. However, the degree of impairment varied by prosodic domains. PWA showed pronounced difficulties in word- and sentence-level prosodic perception, while their perception of discourse-level prosody appeared relatively preserved. Meta-regression analyses identified several key moderators of prosodic performance, including age, aphasia type, response modality, and stimulus type. Larger effect sizes were associated with older age, a higher proportion of non-fluent aphasia, the use of visual symbol choices as task responses, and semantically meaningful stimuli. Conclusion The results confirmed a significant deficit in prosodic perception in PWA; however, the severity of this impairment varied across linguistic domains. The domain-dependent pattern offers important insights into the hemispheric organization of prosodic processing. These results have meaningful implications for both the theoretical understanding of language processing and the clinical assessment and rehabilitation of aphasia.

There is a general agreement that speaking requires attention at least for conceptual and lexical processes of utterance production. However, conflicting results have been obtained with dual-task paradigms using either repetition tasks or more generally tasks involving limited loading of lexical selection. This study aimed to investigate whether post-lexical processes recruit attentional resources. We used a new dual-task paradigm in a set of experiments where a continuous verbal production task involved either high or low demand on lexical selection processes. Experiment 1 evaluates lexical and post-lexical processes with a semantic verbal fluency task, whereas Experiments 2 and 3 focus on post-lexical processes with a non-propositional speech task. In each experiment, two types of non-verbal secondary tasks were used: processing speed (simple manual reaction times) or inhibition (Go/No-go). In Experiment 1, a dual-task cost was observed on the semantic verbal fluency task and each non-verbal task. In Experiment 2, a dual-task cost appeared on the non-verbal tasks but not on the speech task. The same paradigm was used with older adults (Experiment 3), as increased effort in post-lexical processes has been associated with ageing. For older adults, a dual-task cost was also observed on the non-propositional verbal task when speech was produced with the inhibition non-verbal task. The results suggest an attentional cost on post-lexical processes and strategic effects in the resolution of the dual-task.

Aphasia is often accompanied by impairment of non-language cognitive functions. Assessment of cognitive capacity in people with aphasia (PWA) with standard neuropsychological methods may be problematic due to their language difficulties. Numerous experimental studies indicate that P300 may be considered as an index of cognitive capacity in both healthy and clinical samples. Accordingly, the measurement of event-related potentials enables the investigation of behaviourally non-observable mental processes underlying the cognitive functions that are assessed with neuropsychological tests. To investigate in PWA the relationship between P300 parameters and cognitive function efficiency measured with neuropsychological methods. A total of 25 PWA after left-hemispheric stroke participated in the study. Electrophysiological (EEG) signals were recorded during the performance of a visual Go-No Go task. P300 was identified on nine electrodes, which were then pooled in three lines: left (F3, C3, P3), central (Fz, Cz, Pz) and right (F4, C4, P4). The neuropsychological assessment of cognitive functions included mental speed, short-term memory, divided attention, executive functions, auditory language comprehension and expression. P300 latency correlated with indices of several cognitive functions: temporal resolution, psychomotor speed, spatial short-term memory, planning, word and sentence comprehension, as well as verbal fluency. Shorter P300 latencies were accompanied by greater efficiency of the abovementioned functions. In contrast, significant correlations between P300 amplitudes and cognitive measures were fragmentary. In PWA, P300 latency might be related to cognitive functioning, especially to measures that rely heavily on the speed of information processing. However, P300 seems to be unrelated to more complex cognitive functions. P300 latency may be used as a neurophysiological correlate of cognitive efficiency in PWA and might have potential applications in monitoring the effects of therapeutic interventions in this patient group. What is already known on the subject P300 parameters have been reported to be associated with cognitive performance in both healthy individuals and clinical groups (e.g., patients with Alzheimer's disease). Previous studies show that the presence of P300 at the early post-stroke stage may be a predictor of better recovery of comprehension in PWA. What this paper adds to existing knowledge Our results show for the first time that P300 may be used as a neurophysiological correlate of cognitive efficiency in PWA. In our study, P300 latency was associated with several languages and non-language cognitive functions, especially with those whose effectiveness depends mainly on processing speed. In PWA, shorter latency corresponded to more efficient cognitive functioning. What are the potential or actual clinical implications of this work? P300 measurement may be potentially useful in assessing the efficiency of certain cognitive functions in PWA. It may be also used to monitor the recovery process of PWA and to verify the effects of therapeutic interventions.

People with aphasia (PWA) can experience functional numeracy difficulties, that is, problems understanding or using numbers in everyday life, which can have numerous negative impacts on their daily lives. There is growing interest in designing functional numeracy interventions for PWA; however, there are limited suitable assessments available to monitor the impact of these interventions. Existing functional numeracy assessments lack breadth and are not designed to be accessible for PWA, potentially confounding their performance. Additionally, they do not include real-life demands, such as time pressure, which may affect their ecological validity. Thus, there is a crucial need for a new assessment to facilitate further research of PWA's functional numeracy. To develop, validate and pilot a wide-ranging, aphasia-friendly functional numeracy assessment to investigate how functional numeracy is impacted by aphasia severity and time pressure demands, and to explore predictors of PWA's functional numeracy. To develop the Functional Numeracy Assessment (FNA), 38 items inspired by the General Health Numeracy Test (GHNT) and Excellence Gateway were adapted for suitability for PWA and entered in a computerized psychometric-style test. The final 23 items (FNA23) were selected based on 213 neurotypical controls' performance, and controlled for difficulty, response modality and required numeracy skills. Aphasia-friendly adaptations of the GHNT and Subjective Numeracy Scale were used to examine the FNA23's concurrent validity. Internal consistency reliability and interrater reliability (for spoken responses) were also examined. A novel Time Pressure Task was created by slight adaptation of seven FNA23 questions to explore the effects of time pressure on functional numeracy performance. A total of 20 PWA and 102 controls completed all measures on an online testing platform. The FNA23 demonstrated acceptable internal consistency reliability (KR-20 = 0.81) and perfect interrater reliability (for spoken responses). FNA23 and GHNT scores were positively associated, suggesting satisfactory concurrent validity. PWA demonstrated poorer functional numeracy than controls and took longer to complete assessments, indicating that aphasia impacts functional numeracy. Time pressure did not significantly impact performance. PWA demonstrated a wide range of functional numeracy abilities, with some performing similarly to controls. The FNA23 is a wide-ranging, valid and reliable assessment which, with further development, will be a useful tool to identify and monitor PWA's functional numeracy difficulties in research and clinical practice. Considering PWA's widespread functional numeracy difficulties evidenced by this study, all PWA would likely benefit from routine evaluation for functional numeracy difficulties as part of their neurorehabilitation journeys. What is already known on this subject Few studies have investigated functional numeracy difficulties in PWA. No published functional numeracy assessments exist that have been specifically designed to be accessible for PWA. What this paper adds to existing knowledge The newly developed FNA23 is a valid and reliable tool to extensively assess PWA's functional numeracy. This study confirmed previous findings of widespread functional numeracy difficulties in PWA that are related to their aphasia severity. What are the potential or actual clinical implications of this work? The FNA23 can be used to assess PWA's functional numeracy to inform areas of strengths and difficulties to target in intervention, and to monitor progress towards achieving intervention objectives. All PWA should be routinely evaluated for functional numeracy difficulties.

People with aphasia (PWA) typically exhibit deficits in spoken discourse. Discourse analysis is the gold standard approach to assess language deficits beyond sentence level. However, the available discourse assessment tools are biased towards English and European languages and Western culture. Additionally, there is a lack of consensus on which discourse measures to use and limited evidence of the psychometric properties of published discourse measurements. (1) To develop a standardized, norm-referenced, culturally and linguistically appropriate Arabic Discourse Assessment Tool (ADAT); and (2) to examine the psychometric properties of content and construct validity and interrater reliability of different discourse measures elicited using three discourse genres (descriptive, narrative and procedural) in neurotypical control adults and matched PWA. Discourse samples were collected using three novel discourse stimuli that are sensitive to the Arabic language and culture from 70 neurotypical control adults and a matched group of 50 PWA. Transcription agreement was assessed. A standard approach was used to evaluate construct validity and interrater reliability for 16 discourse measures that assess fluency, language productivity, information content, lexical-semantics, lexical diversity, grammatical category, grammatical structure and syntactic complexity. Strong measures were identified based on their psychometric properties, and normative data were established on these measures. Discourse performance of PWA was then examined using the newly developed tool (ADAT). Transcription agreement was extremely high for all discourse stimuli in both groups. Eight discourse measures were proven to have consistently very high construct validity and consistently very good to excellent reliability across the three stimuli in both neurotypical control and aphasia groups: lexical information units, content information units, words per minute, discourse duration, number of different words, number of complete sentences and proportion of open and closed class words. Norms were established on these measures, and cut-off scores of impairments were determined. Other measures showed low construct validity and variable or poor reliability across the two groups. The newly developed, standardized, and norm-referenced tool(ADAT) consist of three discourse stimuli and eight high-quality discourse measures that assess multiple aspects of spoken discourse and were able to differentiate PWA from neurotypical adults consistently. ADAT also includes normative data and cut-off impairment scores. The tool has great potential to enhance clinical practice and research with Arabic speakers. Evidence was provided that not all discourse measures are of high quality, as some are vulnerable to differences between raters, discourse stimuli and groups. Clinicians and researchers can use ADAT for accurate aphasia assessments, better management plans and to monitor therapy effectiveness. ADAT can be further validated in other clinical populations with language impairments. What is already known on the subject Discourse analysis is the gold standard approach to assess language deficits beyond sentence level. However, existing discourse assessment tools are biased towards English and European languages and Western culture. Additionally, there is a lack of consensus on which discourse measures to use in aphasia, and limited evidence of the psychometric properties of published discourse measurements. What this paper adds to existing knowledge A novel, standardized, norm-referenced Arabic Discourse Assessment Tool (ADAT) was developed and validated in this study. ADAT was further validated among PWA. The study provides evidence that not all discourse measures are of high quality and thus should not be used with confidence. Specific measures are vulnerable to the type of stimuli, the rater and/or the tested group. On the other hand, eight discourse measures were identified to be reliable between different raters and across different stimuli for the two groups, and they were able to differentiate the discourse performance of PWA from neurotypical control adults. Normative data derived from neurotypical control adults were established on these strong measures, and the performance of PWA was classified as impaired based on these norms. What are the potential or actual clinical implications of this work? The present study provides a novel, standardized, norm-referenced, validated discourse assessment tool that is culturally and linguistically appropriate for use by Arabic speakers (ADAT). ADAT holds immense potential to enhance clinical practice and research with Arabic speakers. The study also identified strong discourse measures that can be used to assess language productivity, information content, lexical-semantics, lexical diversity, grammatical category, and syntactic complexity for accurate and comprehensive assessments. This will lead to better rehabilitation management by guiding the development of tailored client-centred interventions. ADAT can be utilized in clinical and research settings in PWA and has the potential to be further validated with other clinical populations.

Objective: The goal of this study was to determine whether the regions of the prefrontal and parietal cortices showing abnormal activation among individuals with schizophrenia during working memory tasks are associated with either 1) phonological coding processes that may be specific to verbal tasks (i.e., ventral prefrontal and parietal cortices) or 2) domain-general executive processes engaged by verbal and nonverbal tasks (i.e., dorsal prefrontal and parietal cortices). Method: The participants were 57 medicated individuals with schizophrenia and 120 healthy subjects. Functional magnetic resonance imaging was used to scan all participants during performance of verbal and nonverbal 2-back working memory tasks. Results: In the healthy subjects there was similar bilateral dorsal prefrontal and inferior parietal cortex activation for both the verbal and nonverbal working memory tasks, but greater left ventral prefrontal and parietal cortex activation during verbal compared to nonverbal working memory. Individuals with schizophrenia showed bilateral deficits in dorsal frontal and parietal activation during both verbal and nonverbal working memory tasks. They also demonstrated the typical pattern of greater activity for verbal, as compared to nonverbal, working memory in ventral prefrontal and parietal regions, although they showed less verbal superiority in a left ventral prefrontal region. Conclusions: These results support the hypothesis that working memory deficits in individuals with schizophrenia reflect deficits in activation of brain regions associated with the central executive components of working memory rather than domain-specific storage buffers.

The goal of this study was to determine whether the regions of the prefrontal and parietal cortices showing abnormal activation among individuals with schizophrenia during working memory tasks are associated with either 1) phonological coding processes that may be specific to verbal tasks (i.e., ventral prefrontal and parietal cortices) or 2) domain-general executive processes engaged by verbal and nonverbal tasks (i.e., dorsal prefrontal and parietal cortices). The participants were 57 medicated individuals with schizophrenia and 120 healthy subjects. Functional magnetic resonance imaging was used to scan all participants during performance of verbal and nonverbal 2-back working memory tasks. In the healthy subjects there was similar bilateral dorsal prefrontal and inferior parietal cortex activation for both the verbal and nonverbal working memory tasks, but greater left ventral prefrontal and parietal cortex activation during verbal compared to nonverbal working memory. Individuals with schizophrenia showed bilateral deficits in dorsal frontal and parietal activation during both verbal and nonverbal working memory tasks. They also demonstrated the typical pattern of greater activity for verbal, as compared to nonverbal, working memory in ventral prefrontal and parietal regions, although they showed less verbal superiority in a left ventral prefrontal region. These results support the hypothesis that working memory deficits in individuals with schizophrenia reflect deficits in activation of brain regions associated with the central executive components of working memory rather than domain-specific storage buffers.