Resting state correlates of picture description informativeness in left vs. right hemisphere chronic stroke.

Introduction: Despite a growing emphasis on discourse processing in clinical neuroscience, relatively little is known about the neurobiology of discourse production impairments. Individuals with a history of left or right hemisphere stroke can exhibit difficulty with communicating meaningful discourse content, which implies both cerebral hemispheres play a role in this skill. However, the extent to which successful production of discourse content relies on network connections within domain-specific vs. domain-general networks in either hemisphere is unknown. Methods: In this study, 45 individuals with a history of either left or right hemisphere stroke completed resting state fMRI and the Cookie Theft picture description task. Results: Participants did not differ in the total number of content units or the percentage of interpretative content units they produced. Stroke survivors with left hemisphere damage produced significantly fewer content units per second than individuals with right hemisphere stroke. Intrinsic connectivity of the left language network was significantly weaker in the left compared to the right hemisphere stroke group for specific connections. Greater efficiency of communication of picture scene content was associated with stronger left but weaker right frontotemporal connectivity of the language network in patients with a history of left hemisphere (but not right hemisphere) stroke. No significant relationships were found between picture description measures and connectivity of the dorsal attention, default mode, or salience networks or with connections between language and other network regions. Discussion: These findings add to prior behavioral studies of picture description skills in stroke survivors and provide insight into the role of the language network vs. other intrinsic networks during discourse production.

Core lexicon in aphasia: A longitudinal study.

Background: General consensus exists between clinicians as to the incorporation of discourse outcome measures into language assessment for persons with aphasia (PWA). The development of core lexicon measures (CoreLex) has enabled clinicians to reduce time and labor intensive preparatory work for discourse analysis, which has been considered as an alternative measure to quantify word retrieval ability in discourse in a clinical context. Although previous studies have investigated the quality of the measure, CoreLex has rarely been longitudinally explored. Aims: We aimed to investigate the adequacy of CoreLex to document linguistic changes in PWA over time. Specifically, we examined (1) whether natural language recovery from acute to chronic stages is manifested differentially by tasks and (2) the extent to which the ability to retrieve words in isolation predicts the ability to retrieve words in context. Methods: A total of 19 PWA participated in the study. They completed a language assessment including confrontation naming tasks (Boston Naming Test [BNT] and Hopkins Action Naming Assessment [HANA]) and a picture description task using the Cookie Theft picture at acute and chronic stages. Discourse samples from the picture description task were quantified using CoreLex. Results: We found significant differences across tasks and time-points by PWA. Moderate correlations between the confrontation naming tasks and CoreLex were found at the acute stage but not at the chronic stage. Additionally, McNemar's tests demonstrated a significant difference in PWA's performance in CoreLex from the acute to the chronic stages. Conclusions: Our findings show that performance by PWA improves over time on all tasks, but language gains are manifested differentially by tasks. Performance in confrontation naming moderately predicts word retrieval in context acutely. However, lack of correlations between confrontation naming tasks and CoreLex later endorse inadequacy of using confrontation naming tasks as a proxy measure for discourse-level performance and improvement for PWA.

An Analysis of Right Hemisphere Stroke Discourse in the Modern Cookie Theft Picture.

PURPOSE: Adults with right hemisphere damage demonstrate differences in connected speech compared to controls, but systematic, quantitative methods to capture these differences are lacking. The current study aimed to (a) investigate if measures using the Modern Cookie Theft picture description would identify discourse differences in acute right hemisphere stroke, and (b) examine if discourse differences were associated with documented cognitive impairment. METHOD: Eighty-four participants completed the Modern Cookie Theft picture description within 5 days of right hemisphere stroke. Descriptions were analyzed for multiple microlinguistic characteristics. Medical charts were retrospectively reviewed for documented presence of cognitive impairment. RESULTS: Individuals with acute right hemisphere stroke produced fewer content units, total syllables, and lower left-right content unit ratios compared to controls, indicating a paucity of informativeness. Presence of cognitive impairment was associated with fewer content units produced. CONCLUSIONS: Multiple measures of microlinguistic discourse characteristics differentiated adults with right hemisphere stroke from controls, highlighting variations in both the quantity and quality of connected speech. Findings continue to underscore the contribution and correlation between cognitive skills and discourse performance. Future work is needed to assess the relationship between particular cognitive domains and discourse production as well as to investigate longitudinal changes to discourse production during stroke recovery. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.20778541.

Differences in linguistic cohesion within the first year following right and left hemisphere lesions.

BACKGROUND: Characterizing productive language deficits following lesions to the right (RH) or left hemispheres (LH) is valuable in identifying appropriate therapeutic goals. While damage to the LH classically is associated with deficits in language, RH lesions also result in changed communication beyond prosody due to cognitive-linguistic effects. Cohesion, reference to introduced content across sentences within discourse, relies on a listener's clear and unambiguous understanding that a reference has occurred. To date, we are not aware of any prior work that has compared patterns of cohesive strategy between RH and LH lesioned individuals with cohesion deficits. AIMS: The purpose of the present study is to determine whether individuals with communication deficits following RH and LH lesions differ in the inclusion and clarity of cohesive markers. METHODS & PROCEDURES: Seventy-six RH samples and 145 LH samples were used for comparison of cohesion performance in a Cookie Theft picture description task. Cohesive ties were assessed following the protocol outlined in Liles and Coelho (1998). It was hypothesized that individuals with LH lesions would present a different pattern of cohesion behaviour than RH lesioned individuals when considered both acutely and chronically. OUTCOMES & RESULTS: Overall, samples from LH and RH groups did not differ in word counts or cohesive marker usage. However, the patterns of markers they chose to employ were different. LH samples used conjunctions and personal pronouns more frequently and used lexical cohesive markers less frequently than RH samples. Acutely, patterns of cohesive marker use between LH and RH samples were more similar. Chronically, LH samples contained more personal pronouns and the differences in lexical cohesive markers remained unchanged. When cohesion was unsuccessful, LH and RH damage were associated with different patterns of error. LH samples tended to omit information needed to clarify the intended referent, resulting in incomplete cohesion errors. RH samples tended to sustain breakdowns in cohesion from sentence to sentence, not resolving incorrectly chosen pronouns or ambiguities left in their samples. CONCLUSIONS: LH and RH lesions resulted in differing patterns of chosen cohesive markers and errors when cohesion was unsuccessful. This was particularly true in lexical cohesion, which has been far less studied than closed-class cohesive markers like referential pronouns. It was also noted that cohesive behavior did not appear to "recover" for either group, suggesting spontaneous recovery is minimal and present strategies for language therapy may not effectively address this linguistic function.

Stealing Cookies in the Twenty-First Century: Measures of Spoken Narrative in Healthy Versus Speakers With Aphasia.

Purpose Our goal was to evaluate an updated version of the "Cookie Theft" picture by obtaining norms based on picture descriptions by healthy controls for total content units (CUs), syllables per CU, and the ratio of left-right CUs. In addition, we aimed to compare these measures from healthy controls to picture descriptions obtained from individuals with poststroke aphasia and primary progressive aphasia (PPA) to assess whether these measures can capture impairments in content and efficiency of communication. Method Using an updated version of this picture, we analyzed descriptions from 50 healthy controls to develop norms for numbers of syllables, total CUs, syllables per CU, and left-right CU. We provide preliminary data from 44 individuals with aphasia (19 with poststroke aphasia and 25 with PPA). Results A total of 96 CUs were established based on the written transcriptions of spoken picture descriptions of the 50 control participants. There was a significant effect of group on total CUs, syllables, syllables per CU, and left-right CUs. The poststroke participants produced significantly fewer total CU and syllables than those with PPA. Each aphasic group produced significantly fewer total CUs, fewer syllables, more syllables per CU, and lower left-right CUs (indicating a right-sided bias) compared to controls. Conclusions Results show that the measures of numbers of syllables, total CUs, syllables per CU, and left-right CUs can distinguish language output of individuals with aphasia from controls and capture impairments in content and efficiency of communication. A limitation of this study is that we evaluated only 44 individuals with aphasia. In the future, we will evaluate other measures, such as CUs per minute, lexical variability, grammaticality, and ratio of nouns to verbs. Supplemental Material https://doi.org/10.23641/asha.7015223.