Jennifer Mozeiko

Discourse production following injury to the dorsolateral prefrontal cortex.

Individuals with damage to the prefrontal cortex, and the dorsolateral prefrontal cortex (DLPFC) in particular, often demonstrate difficulties with the formulation of complex language not attributable to aphasia. The present study employed a discourse analysis procedure to characterize the language of individuals with left (L) or right (R) DLPFC lesions. All participants were 30-35 years post-onset of injury and presented with persistent discourse impairments. The discourse performance of the R DLPFC group was not significantly different from either the L DLPFC group or the non-injured comparison group. Individuals from the L DLPFC group demonstrated specific difficulties with narrative coherence and inclusion of critical story components. Both measures were significantly different from the comparison group. The discourse ability of the DLPFC groups was significantly correlated with measures of working memory. Findings support the use of discourse analysis for examining language impairments in individuals with PFC lesions.

The relationship of story grammar and executive function following TBI

Background: Story grammar is a super-structural measure of discourse performance that has shown to be sensitive to the deficits seen following traumatic brain injury (TBI). Narrative organisation and identification of logical relationships between events and characters are key components of story grammar. Reports of significant correlations for measures of story grammar and scores from various tests of executive functioning for individuals with TBI are thought to reflect executive control of cognitive and linguistic organisational processes. Aims: The purpose of the present study was to re-examine the relationship between story grammar and executive functions (EF) in a large group of participants with severe TBI secondary to diverse penetrating head wounds. It was hypothesised that participants with TBI would have significantly lower story grammar scores than a comparison group without TBI, and that story grammar performance of the group with TBI would be significantly correlated with their EF scores. Methods & Procedures: A total of 167 participants with TBI and a comparison group of 46 adults without TBI were asked to retell a 16-frame story. Transcripts of each story retelling were broken into T-units and were analysed for story grammar. Outcomes & Results: Results of MANOVA showed significant effect of group on the discourse measures. Univariate tests showed significant differences between the group with TBI and the comparison group for each of the story grammar measures. Story grammar measures were significantly correlated with executive function (EF) scores. Conclusions: Results indicated that the participants with TBI demonstrated significantly poorer performance on measures of story grammar abilities, lending support to earlier reports of story grammar impairments resulting from closed head injury (CHI). The present study also found significant correlations for measures of story grammar and the Sorting Test. Cognitive skills such as mental flexibility, required for successful performance on this card sorting task are likely the same as those required for episode generation. These findings have clinical implications for the management of cognitive-communication disorders in individuals with TBI. First, story grammar warrants inclusion in analyses of discourse. Second, discourse deficits following brain injury do not resolve spontaneously and persist as social barriers.

Measuring goodness of story narratives: Implications for traumatic brain injury

Background: This study examined the utility of story “goodness”, a measure of organisation and completeness, in quantifying narrative discourse deficits following traumatic brain injury (TBI). In an initial study, the story goodness measure demonstrated sensitivity and reliability in distinguishing individuals who had TBI from those who were non-brain-injured. Aims: The purpose of the current study was to validate previous findings of the story goodness index, specifically in discriminating performance between groups and identifying performance subgroups, in a larger sample of participants with TBI. Methods & Procedures: A total of 46 non-brain-injured adults and 171 adults with TBI participated. Story retellings were analysed for story grammar and story completeness. The two discourse scores were then plotted as coordinates, which allowed for quantification of story goodness. Statistical analyses included a multivariate analysis of variance and calculation of Pearson correlation coefficients for the discourse measures. Outcomes & Results: Results indicated that participants’ scores clustered differentially across quadrants between groups and discriminated groups into four distinct categories of story “goodness”. Conclusions: Findings paralleled those found in the initial study, suggesting that story goodness is a sensitive measure for examining the discourse of individuals with TBI. The story goodness has potential clinical utility and may have implications for investigation of discourse impairments in other clinical populations and treatment of discourse deficits.

Does Brain Volume Loss Predict Cognitive and Narrative Discourse Performance Following Traumatic Brain Injury

PURPOSE In this study, the authors investigated the relationship between brain volume loss and performance on cognitive measures, including working memory, immediate memory, executive functions, and intelligence, and a narrative discourse production task. An underlying goal was to examine the prognostic potential of a brain lesion metric for discourse outcomes. It was hypothesized that brain volume loss would correlate with and predict cognitive and narrative discourse measures and have prognostic value for discourse outcomes. METHOD One hundred sixty-seven individuals with penetrating head injury participated. Correlational and regression analyses were performed for the percentages of total brain and hemispheric volume loss and scores on 4 cognitive measures (WMS-III Working Memory and Immediate Memory primary indexes, D-KEFS Sorting Test, and WAIS-III Full Scale IQ) and 7 narrative discourse measures (T-units, grammatical complexity, cohesion, local and global coherence, story completeness, and story grammar). RESULTS The volumetric measures had significant small-to-moderate correlations with all cognitive measures but only one significant correlation with the discourse measures. Findings from regression analyses were analogous but revealed several models that approached significance. CONCLUSION Findings suggest that an overall measure of brain damage may be more predictive of general cognitive status than of narrative discourse ability. Atrophy measures in specific brain regions may be more informative.

Discourse characteristics of closed-head-injured and non-brain-injured adults misclassified by discriminant function analyses

Background: In a previous study, discriminant function analyses (DFA) were employed to determine the accuracy of various story narrative and conversational discourse measures in classifying non-brain-injured (NBI) and closed-head-injured (CHI) adults (Coelho, Youse, Le, & Feinn, 2003). The DFAs correctly predicted group membership with 70–81% accuracy.Aims: The present study re-examined the performance of the CHI and NBI participants who were incorrectly classified in an effort to determine what aspects of their discourse performance contributed to the misclassifications. It was hypothesised that the misclassifications were due to the relatively broad range in performance on the discourse measures, resulting in considerable overlap between the NBI and CHI participants.Methods & Procedures: Scores for the story narrative and conversational discourse measures that made the largest contribution to the correct classification of the two participant groups were re-examined for the CHI and NBI participants who were misclassified by the DFA in the previous study (Coelho et al., 2003).Outcomes & Results: Results indicated that there was considerable overlap in the discourse performance of the two participant groups for several of the story narrative and conversational discourse measures.Conclusions: The performance overlaps occurred on many of the same discourse measures that were noted to be fairly good discriminators of CHI versus NBI discourse performance in the original study. Consequently, recommendations regarding elimination of certain measures to streamline the discourse analysis procedure could not be made. Other factors such as sampling discourse acontextually and specific participant characteristics undoubtedly influenced these findings as well. In addition, the DFA procedure utilised in the original study did not take into account the heterogeneity of discourse data. Nonparametric procedures such as classification and regression trees (CART) (Breiman, Friedman, Olshen, & Stone, 1984; Johnson & Wichern, 2002) may be better suited for the classification of non-homogeneous populations such as individuals with CHI.

The role of intensity in constraint-induced language therapy for people with chronic aphasia

Background: Studies of intensive aphasia treatments vary widely in terms of treatment focus, in patient population and, in particular, in definition of what is considered “intensive”. Variability makes it difficult to compare among studies and to definitively determine whether more treatment is actually better. Constraint-induced language therapy (CILT) is one treatment that has been successfully replicated at approximately the same dosage with generally positive results. Aims: The current study used a modified multiple baseline design across participants to investigate the administration of CILT at the standard intensive dosage of 30 hours over 2 weeks (CILT-I) compared to a more distributed dosage of 30 hours over 10 weeks (CILT-D). Methods & Procedures: Eight participants with chronic aphasia participated in either CILT-I or CILT-D. Standardised and discourse measures were taken pre- and post-treatment and also 4 weeks after the completion of treatment. Discourse probes were administered after every 6 hours of treatment to assess change in productivity and efficiency over time. Outcomes & Results: All of the participants who received CILT-I and CILT-D showed either an increased effect size on a discourse measure, a clinically significant change on a standardised battery or both. Gains were maintained in nearly all cases. Conclusions: CILT administered in both intensive and distributed dosages resulted in positive changes in aphasia severity and discourse. This study adds evidence to the still inconclusive role of intensity to CILT.

Changes in discourse structure over time following traumatic brain injury

ABSTRACT The objective of the present study was to investigate structural changes in the narrative discourse of individuals with penetrating traumatic brain injury (pTBI) following immediate and delayed story retellings. Additionally, the potential influence of immediate memory, working memory, and executive functions on narrative discourse performance were examined. The narrative discourse of two groups, 123 with pTBI and 44 non‐brain injured (NBI), was sampled. Participants were asked to retell a wordless picture story immediately after viewing it and again 30‐min later. Story narratives were analyzed using a variety of microlinguistic and macrostructural measures. Results revealed significant group differences of both microlinguistic and macrostructural measures following the immediate retell, but not following the delayed retell. Regression analyses revealed that immediate memory accounted for a modest degree of the explained variance for the production of critical content during narrative discourse. The observed deficits were relatively stable over a short delay (30 min) and appeared attributable, in part, to difficulty with the encoding and consolidation of story content. HighlightsTraumatic brain injury can result in discourse deficits.Discourse deficits reflect disruptions to cognitive‐linguistic processing.Discourse deficits are observed at both microlinguistic and macrostructural levels.Immediate memory influences critical content production during narrative discourse.Encoding and memory consolidation appear linked to critical content production.

Increased connectivity following intensive reading and language treatment for mild, chronic aphasia

Background: Resting state MRI (rsfMRI) is a method of functional brain imaging that can be used to evaluate regional functional connectivity (FC) when a participant is at rest, not responding to task demands. Following stroke, altered connections from lesion to distal brain areas have the potential to change in response to treatment, leading to better recovery. If specific FC patterns are identified as effective in compensating for damaged networks, future treatments may be designed to facilitate these patterns. Little is known about altered network connectivity in people with aphasia (PWA). In 10 rsfMRI studies that examined the language network in PWA, Klingbeil, Wawrzyniak, Stockert, and Saur (2017) reported reduced interhemispheric, ipsilesional, or contralesional intrahemispheric rsFC as a consequence of stroke. In the four studies that have reported results of rsFC following aphasia treatment, improved behavioral performance was correlated with ipsilesional intra-hemispheric and/or inter-hemispheric changes in rsFC. Aims: (1) Better understand the nature of neural recovery in PWA. (2) Assess feasibility of rsFC as a treatment outcome measure.

Reading comprehension treatment in aphasia: a systematic review

ABSTRACT Background: Reading difficulties often present as a consequence of aphasia. The specific nature of reading deficits varies widely in manifestation, and the cause of these deficits may be the result of a phonological, lexical semantic, or cognitive impairment. Several treatments have been developed to address a range of impairments underlying reading difficulty. Aims: The purpose of this review is to describe the current research on reading comprehension treatments for persons with aphasia, assess the quality of the research, and summarize treatment outcomes. Methods & Procedures: A systematic review of the literature was conducted based on a set of a priori questions, inclusion/exclusion criteria, and pre-determined search parameters. Results were summarized according to treatment type, methodologic rigor, and outcomes. Outcomes & Results: Fifteen studies meeting criteria were identified. A variety of reading comprehension treatments was implemented including: oral reading, strategy-based, cognitive treatment, and hierarchical reading treatments. Quality ratings were highly variable, ranging from 3 to 9 (on a 12-point scale). Overall, 14 of the 18 individuals for whom individual data were provided demonstrated some degree of improvement (oral reading 4/5 participants, strategy based 4/6, and cognitive treatment 6/7). Gains were also evident for hierarchical reading treatment administered to participant groups via computer; however, the degree to which improvement reached statistical significance varied among studies. Conclusions: Reading comprehension treatments have the potential to improve reading comprehension ability in persons with aphasia; however, outcomes were variable within and among treatment methods. We suggest focusing future research on factors such as participant candidacy and treatment intensity using increased methodological rigor.