Changes in discourse structure over time following traumatic brain injury

The Relationship Between Executive Functioning and Narrative Language Abilities in Aphasia

PURPOSE

Although individuals with aphasia commonly exhibit challenges in executive functioning (EF) and spoken discourse, there is limited research exploring connections between these abilities within this specific population. Therefore, this study investigated the relationship between verbal and nonverbal EF and narrative productions in aphasia using a multilevel linguistic approach.

METHOD

Participants included 22 persons with aphasia (PWA) and 24 age- and education-matched, neurologically healthy controls (NHC). All participants completed assessments for EF and a story retelling task. Narrative samples were analyzed for microlinguistic (productivity, lexical and syntactic features, semantic content, word and sentence errors) and macrolinguistic (coherence, informational content, organization, and language use) characteristics. Correlational analyses were employed to explore the relationships among narrative variables. EF factors, extracted from principal component analysis, were used as predictive variables in hierarchical stepwise regression analyses to evaluate their role in predicting narrative performances of PWA and NHC.

RESULTS

Relative to NHC, PWA exhibited impaired narrative performance affecting both microlinguistic and macrolinguistic levels. Breakdowns at the structural level (i.e., reduced productivity, syntax, lexical retrieval, and diversity) correlated with impaired story completeness, organization, and connectedness; this relationship was more prominent for PWA. Three EF factors representing (1) verbal EF, (2) verbal and nonverbal fluency, and (3) nonverbal EF were extracted. Factors 1 and 2 largely predicted narrative performance, whereas Factor 3 (i.e., nonverbal EF) contributed prominently to predicting macrolinguistic discourse performance in both groups although accounting for less variance in the data. Overall, lower EF scores, particularly verbal EF variables, predicted poor narrative performance in both groups.

CONCLUSIONS

Our results indicate that both linguistic and extralinguistic cognitive abilities play a role in story retelling performances among PWA. Notably, both verbal and nonverbal EF skills were found to be correlated with narrative abilities. However, the extent of their contributions varied depending on the discourse levels assessed. These findings provide a significant contribution to our understanding of the cognitive factors associated with breakdowns in discourse among PWA and highlight the importance of comprehensive assessment of EF and discourse within this population.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26485627.

Attentional Orienting and Disfluency-Related Memory Boost Are Intact in Adults With Moderate-Severe Traumatic Brain Injury

PURPOSE

Traumatic brain injury (TBI) is associated with a range of cognitive-communicative deficits that interfere with everyday communication and social interaction. Considerable effort has been directed at characterizing the nature and scope of cognitive-communication disorders in TBI, yet the underlying mechanisms of impairment are largely unspecified. The present research examines sensitivity to a common communicative cue, disfluency, and its impact on memory for spoken language in TBI.

METHOD

Fifty-three participants with moderate-severe TBI and 53 noninjured comparison participants listened to a series of sentences, some of which contained disfluencies. A subsequent memory test probed memory for critical words in the sentences.

RESULTS

Participants with TBI successfully remembered the spoken words (b = 1.57, p < .0001) at a similar level to noninjured comparison participants. Critically, participants with TBI also exhibited better recognition memory for words preceded by disfluency compared to words from fluent sentences (b = 0.57, p = .02).

CONCLUSIONS

These findings advance mechanistic accounts of cognitive-communication disorder by revealing that, when isolated for experimental study, individuals with moderate-severe TBI are sensitive to attentional orienting cues in speech and exhibit enhanced recognition of individual words preceded by disfluency. These results suggest that some aspects of cognitive-communication disorders may not emerge from an inability to perceive and use individual communication cues, but rather from disruptions in managing (i.e., attending, weighting, integrating) multiple cognitive, communicative, and social cues in complex and dynamic interactions. This hypothesis warrants further investigation.

Analysis of Discourse Production to Assess Cognitive Communication Deficits Following Mild Traumatic Brain Injury With and Without Posttraumatic Stress

PURPOSE

Cognitive communication deficits can be difficult to assess in individuals with mild traumatic brain injury (mTBI). However, the use of discourse analysis as a direct and sensitive metric of cognitive communication skills has shown promising clinical utility for other TBI severity levels. This exploratory study investigated discourse production in service members and veterans (SMVs) with uncomplicated mTBI with and without posttraumatic stress disorder (PTSD) and SMVs with neither mTBI or PTSD.

METHOD

Fifteen SMVs with mTBI and PTSD, 26 with mTBI, and 25 controls with no brain injury (NBI) and without PTSD were given a wordless picture story to elicit spontaneous discourse. Discourse samples were analyzed for global coherence, word count, the use of negative emotion words, cognitive process words, nonfluencies, and story completeness.

RESULTS

Results revealed a significant difference between the mTBI (Mdn = 3.33) and NBI (Mdn = 3.50) groups, χ²(3) = 6.044, p = .017, ε² = .03, for global coherence. Word count differed significantly between the mTBI + PTSD (Mdn = 135) and NBI (Mdn = 195) groups, χ²(3) = 7.968, p = .006, ε² = .06. No other group differences were observed.

DISCUSSION

Structural features of discourse production may serve as potential markers of cognitive communication deficits in mTBI. Furthermore, PTSD may contribute to verbal fluency deficits in individuals with mTBI. Additional research is needed to develop discourse-related measures that are more sensitive to the effects of mTBI and PTSD.

Main Concept, Sequencing, and Story Grammar Analyses of Cinderella Narratives in a Large Sample of Persons with Aphasia

Recently, a multilevel analytic approach called Main Concept, Sequencing, and Story Grammar (MSSG) was presented along with preliminary normative information. MSSG analyses leverage the strong psychometrics and rich procedural knowledge of both main concept analysis and story grammar component coding, complementing it with easy-to-obtain sequencing information for a rich understanding of discourse informativeness and macrostructure. This study is the next critical step for demonstrating the clinical usefulness of MSSG’s six variables (main concept composite, sequencing, main concept+sequencing, essential story grammar components, total episodic components, and episodic complexity) for persons with aphasia (PWAs). We present descriptive statistical information for MSSG variables for a large sample of PWAs and compare their performance to a large sample of persons not brain injured (PNBIs). We observed significant differences between PWAs and PNBIs for all MSSG variables. These differences occurred at the omnibus group level and for each aphasia subtype, even for PWAs with very mild impairment that is not detected with standardized aphasia assessment. Differences between PWAs and PNBIs were also practically significant, with medium to large effect sizes observed for nearly all aphasia subtypes and MSSG variables. This work deepens our understanding of discourse informativeness and macrostructure in PWAs and further develops an efficient tool for research and clinical use. Future research should investigate ways to expand MSSG analyses and to improve sensitivity and specificity.