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

Apragmatism: The renewal of a label for communication disorders associated with right hemisphere brain damage

BACKGROUND

Right hemisphere communication disorders are neither consistently labelled nor adequately defined. Labels associated with right hemisphere brain damage (RHD) are broad and fail to capture the essence of communication challenges needed for stroke-related service provisions. Determination of rehabilitation needs and best-practice guidelines for the education, management and functional improvement of communication disorders after RHD are all predicated on an apt diagnostic label and disorder characteristics.

AIMS

In this paper apragmatism is proposed as a potential communication-specific diagnostic label for the impairments in communication that occur after RHD. In particular, the researchers aimed: (1) to establish an operational definition of apragmatism; and (2) to describe the linguistic, paralinguistic and extralinguistic communication deficits under the umbrella term apragmatism.

METHODS & PROCEDURES

An international collaborative of researchers with expertise in RHD followed a multilevel approach to consider the utility of apragmatism as a diagnostic label. Adopting the relational approach to concept mapping, the researchers engaged in a series of group meetings to complete four levels of mapping: (1) identify and review, (2) define, (3) expert discussion and (4) label determination.

MAIN CONTRIBUTION

Apragmatism was established as a suitable diagnostic label for the impairments in communication associated with RHD. The paper offers an operational definition and description of the linguistic, paralinguistic and extralinguistic features of apragmatism through evidence summaries and examples from people with RHD retrieved from the RHDBank.

CONCLUSIONS & IMPLICATIONS

The adoption of the term apragmatism offers an opportunity to capture the hallmark of RHD communication deficits. The use of the term is recommended when referencing the pragmatic language impairments in this population. Apragmatism, which may co-occur with or be exacerbated by cognitive impairments, can interfere with the ability to interpret and convey intended meaning and impact the lives of right hemisphere stroke survivors and their families.

WHAT THIS PAPER ADDS

What is already known on the subject RHD results in a heterogeneous group of deficits that range in cognitive-communicative complexity. Many of the deficits are subsumed under pragmatics. For example, adults with RHD may demonstrate tangential or verbose communication, insensitivity to others' needs and feelings, prosodic changes, minimal gesture use and facial expression, and more. While descriptions of pragmatic impairments pervade the literature, there is no consistently used diagnostic label. The clinical consequences of this absence include difficulty with inter- and intra-disciplinary communication about these patients, difficulty consolidating findings across research studies, and challenges in communicating about these pragmatic changes with patients, families and other stakeholders. What this paper adds to existing knowledge The term apragmatism is proposed as a diagnostic label to consistently describe pragmatic communication changes after RHD. Apragmatism is characterized using three components of pragmatics: linguistic, paralinguistic and extralinguistic. Descriptions and examples of these three components are provided with supplemental transcripts retrieved from the RHDBank. What are the potential or actual clinical implications of this work? Adoption of the term apragmatism by speech and language therapists and other medical and rehabilitation professionals has the potential to provide consistency in describing the abilities and challenges experienced by people following a right hemisphere stroke. Such improvements may help drive the development of evidence-based assessments and treatments for this population.

The longitudinal trajectory of discourse from the hyperacute to the chronic phase in mild to moderate poststroke aphasia recovery: A case series study

BACKGROUND

Discourse analysis has recently received much attention in the aphasia literature. Even if post-stroke language recovery occurs throughout the longitudinal continuum of recovery, very few studies have documented discourse changes from the hyperacute to the chronic phases of recovery.

AIMS

To document a multilevel analysis of discourse changes from the hyperacute phase to the chronic phase of post-stroke recovery using a series of single cases study designs.

METHODS & PROCEDURES

Four people with mild to moderate post-stroke aphasia underwent four assessments (hyperacute: 0-24 h; acute: 24-72 h; subacute: 7-14 days; and chronic: 6-12 months post-onset). Three discourse tasks were performed at each time point: a picture description, a personal narrative and a story retelling. Multilevel changes in terms of macro- and microstructural aspects were analysed. The results of each discourse task were combined for each time point. Individual effect sizes were computed to evaluate the relative strength of changes in an early and a late recovery time frame.

OUTCOMES & RESULTS

Macrostructural results revealed improvements throughout the recovery continuum in terms of coherence and thematic efficiency. Also, the microstructural results demonstrated linguistic output improvement for three out of four participants. Namely, lexical diversity and the number of correct information units/min showed a greater gain in the early compared with the late recovery phase.

CONCLUSIONS & IMPLICATIONS

This study highlights the importance of investigating all discourse processing levels as the longitudinal changes in discourse operate differently at each phase of recovery. Overall results support future longitudinal discourse investigation in people with post-stroke aphasia.

WHAT THIS PAPER ADDS

What is already known on the subject Multi-level discourse analysis allows for in-depth analysis of underlying discourse processes. To date, very little is known on the longitudinal discourse changes from aphasia onset through to the chronic stage of recovery. This study documents multi-level discourse features in four people with mild to moderate aphasia in the hyperacute, acute, subacute and chronic stage of post-stroke aphasia recovery. What this paper adds to existing knowledge The study found that most discourse variables demonstrated improvement throughout time. Macrostructural variables of coherence and thematic units improved throughout the continuum whereas microstructural variables demonstrated greater gains in the early compared to the late period of recovery. What are the potential or actual clinical implications of this work? This study suggests that multilevel discourse analysis will allow a better understanding of post-stroke aphasia recovery, although more research is needed to determine the clinical utility of these findings. Future research may wish to investigate longitudinal discourse recovery in a larger sample of people with aphasia with heterogenous aphasia profiles and severities.

Verbosity with retelling: Narrative discourse production in temporal lobe epilepsy

To examine micro- and macrolinguistic underpinnings of circumstantiality in temporal lobe epilepsy (TLE), we examined the elicited narrative output of 15 individuals with TLE and 14 controls. To replicate and extend Field and colleagues' (2000) work, participants were asked to produce five immediately consecutive elicitations of an eight-frame cartoon "Cowboy Story" (Joanette et al., 1986). Following transcription and coding, detailed multi-level discourse analysis demonstrated a typical pattern of compression in controls. The narratives produced by individuals with TLE were less fluent, cohesive, and coherent across trials: producing fewer novel units and more repetitive and extraneous content. Significant group by trial interactions in sample length, spontaneous duration, and statements, were not explained by seizure burden, age, or lexical retrieval deficits. These findings suggest that they do not benefit from repeated engagement with a narrative in the same manner as controls. Disturbed social cognition and pragmatics in TLE might underpin communication inefficiencies.

Vague retellings of personal narratives in temporal lobe epilepsy

PURPOSE

Aside from deficits identified in single-word level retrieval, individuals with temporal lobe epilepsy (TLE) exhibit clinical oddities, such as circumstantiality in their language production. Circumstantiality refers to the use of language which is pedantic, repetitive, and overly detailed. This becomes particularly evident when elicitation tasks impose minimal structure, or when impersonal narratives are retold over consecutive occasions. Personal reminiscence is highly specific and localised in time, placing unique demands on cognitive-linguistic systems. It is hypothesised that the nature of this elicitation paradigm will produce a unique psycholinguistic phenotype in those with TLE. Among controls there is a compression of output for impersonal narratives, meaning that they use fewer words over less time and are more fluent. The opposite effect is observed when personal narratives are retold.

METHODS

To investigate the micro- and macrolinguistic processes underpinning personal discourse production in TLE, we examined the elicited language output of 15 surgically naïve individuals with TLE and 14 healthy controls. Participants were asked to recall and re-tell an autobiographical memory on four immediately consecutive occasions, representing an alternative unstructured elicitation. Following transcription and coding of output, a detailed multi-level discourse analysis of output volume, fluency, cohesion, and coherence was conducted.

RESULTS

As anticipated, a distinctly different pattern emerged in TLE when compared with controls who did not compress their output volume across repetitions but instead produced greater novelty, and a more coherent and refined account over time. Individuals with TLE consistently told a less distinct story across repetitions, with disturbances in fluency, cohesion, and coherence.

CONCLUSION

This reflects a reduced capacity to produce a coherent mental representation, in all likelihood related to the neurolinguistic demands of recalling and retelling specific personal events.

Anterior connectivity critical for recovery of connected speech after stroke

Connected speech recovers to different degrees across people after left hemisphere stroke, but white matter predictors of differential recovery from the acute stage of stroke are unknown. We assessed changes in lexical-syntactic aspects of connected speech in a longitudinal analysis of 40 individuals (18 females) from the acute stage of left hemisphere stroke (within an average of 4 days post-stroke) to subacute (within 2 months) and chronic stages (early: 6 months, late: 1 year) while measuring the extent of acute lesions on white matter tracts to identify tracts predictive of recovery. We found that acute damage to the frontal aslant tract led to a decreased recovery of the fluency and structural complexity of connected speech during the year following left hemisphere stroke. The results were independent of baseline performance, overall lesion volume and the proportion of damage to tract-adjacent grey matter. This longitudinal analysis from acute to chronic stroke provides the first evidence that recovery of fluent and structurally complex spontaneous connected speech requires intact left frontal connectivity via the frontal aslant tract. That the frontal aslant tract was critical for recovery at early as well as later stages of stroke demonstrates that anterior connectivity plays a lasting and important role for the reorganization of function related to the successful production of connected speech.

Clinical Guidelines for Eliciting Discourse Using the RHDBank Protocol

PURPOSE

Examining discourse after right hemisphere brain damage (RHD) can provide invaluable clinical data and insight into functional communication capabilities. Yet, clinicians preparing to enter the field may have limited experience eliciting and analyzing discourse for therapeutic purposes. The purpose of this work is to present a practical guide for the clinical use of the RHDBank protocol.

METHOD

Following a brief overview of the RHDBank protocol, elicitation guidelines and protocol administration considerations are offered. Measures that should be considered when analyzing RHDBank-elicited discourse are summarized. The RHDBank protocol is positioned as an accessible resource for discourse elicitation in the clinical setting, and examples for the clinical use of the protocol are provided.

CONCLUSIONS

Discourse production can be a key source of information regarding communication ability following RHD. The RHDBank provides a structured and scripted approach to the clinical elicitation of language and consideration of discourse production. Its immediate clinical utility will assist developing clinicians with the acquisition of a clinically relevant elicitation approach and more comprehensive view of the RHD communication impairments. Application of the protocol can aid in collective knowledge advancement that will promote a better understanding of RHD language production as a clinical entity with an array of possible characteristics.

Macrostructural Aspects in Oral Narratives in Brazilian Portuguese by Left and Right Hemisphere Stroke Patients With Low Education and Low Socioeconomic Status

OBJECTIVE

Individuals with a stroke in either the left hemisphere (LH) or the right hemisphere (RH) often present macrostructural impairments in narrative abilities. Understanding the potential influence of low education and low socioeconomic status (SES) is critical to a more effective assessment of poststroke language. The first aim was to investigate macrostructural processing in low-education and low-SES individuals with stroke in the LH or RH or without brain damage. The second aim was to verify the relationships between macrolinguistic, neuropsychological, and sociodemographic variables.

METHOD

Forty-seven adults with LH (n = 15) or RH (n = 16) chronic ischemic stroke and 16 matched (age, education, and SES) healthy controls produced three oral picture-sequence narratives. The macrostructural aspects analyzed were cohesion, coherence, narrativity, macropropositions, and index of lexical informativeness and were compared among the three groups. Then, exploratory correlations were performed to assess associations between sociodemographic (such as SES), neuropsychological, and macrostructural variables.

RESULTS

Both the LH and the RH presented impairments in the local macrostructural aspect (cohesion), whereas the RH also presented impairments in more global aspects (global coherence and macropropositions). All five macrostructural variables correlated with each other, with higher correlations with narrativity. Naming was correlated with all macrostructural variables, as well as prestroke reading and writing habits (RWH), showing that higher naming accuracy and higher RWH are associated with better macrostructural skills.

CONCLUSIONS

The present results corroborate the role of the LH in more local processing and that of the RH in more global aspects of discourse. Moreover, this study highlights the importance of investigating discourse processing in healthy and clinical populations of understudied languages such as Brazilian Portuguese, with various levels of education, SES, and RWH.

Cognitive-communication disorder following right hemisphere damage: Narrative production

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Cognitive-communication disorder (CCD) is a common finding after RH damage.

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Alterations in discourse processing are highly prevalent in CCD.

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We analyzed 1,625 narratives to identify linguistic alterations related to RH lesions.

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The RH group produced narratives with more words, utterances, coherence errors, and lesser degree of information.

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CCD must be addressed through rehabilitation efforts to avoid restrictions on people's everyday life.

Background

Cognitive-communication disorder (CCD) results from the association of language and cognition impairment that may follow right hemisphere (RH) damage and impair the quality of life of affected persons.

Objective

We studied a set of 1,625 narratives produced by a cohort of 125 individuals (50 with a single right vascular lesion in the MCA territory and 75 cognitively healthy controls) using a task of picture-based discourse production. Discourse production was analyzed in its macro-and microlinguistic aspects to characterize better the linguistic mechanisms underlying RH patients' performance.

Results

The RH group produced more words and elocutions than controls, with a lower rate of informational content and a higher percentage of global coherence errors (all p-values <0.0001).

Conclusion

Individuals with RH lesions showed formal lexical and syntactic aspects of discourse mostly preserved. Alterations in the macrostructure of discourse prevailed over microstructural alterations in our sample, according to most literature studies. The group of individuals with RH lesions produced narratives containing more words and utterances, with a lesser degree of lexical information and more global coherence errors.

The role of microstructural integrity of major language pathways in narrative speech in the first year after stroke

BACKGROUND AND PURPOSE

Left hemisphere stroke often results in a variety of language deficits due to varying patterns of damage to language networks. The Cookie Theft picture description task, a classic, quick bedside assessment, has been shown to quantify narrative speech reliably. In this study, we utilized diffusion tensor imaging (DTI) to assess language network white matter tract correlates of lexical-semantic and syntactic impairments longitudinally.

METHODS

Twenty-eight patients with mild to severe language impairments after left hemispheric lobar and/or subcortical ischemic stroke underwent the Cookie Theft picture description test and DTI up to three different time points: within the first three months, six months and twelve months after stroke. Dorsal and ventral stream language pathways were segmented to obtain DTI integrity metrics of both hemispheres. Multivariable regression models and partial correlation analyses adjusted for age, education, and lesion load were conducted to evaluate the temporal DTI profile of the white matter microstructural integrity of the language tracts as neural correlates of narrative speech within the first year after stroke.

RESULTS

Among all the major language white matter pathways, the integrity of the left arcuate (AF), inferior fronto-occipital, and inferior longitudinal fasciculi (ILF) were related to picture description performance. After FDR correction, left ILF fractional anisotropy correlated with syntactic cohesiveness (r=0.85,p=0.00087) within the first three months after stroke, whereas at one year post-stroke, the strongest correlations were found between lexical-semantic performance and left AF radial diffusivity (r = -0.71, p = 0.00065).

CONCLUSION

Our study provides a temporal profile of associations between the integrity of the main language pathways and lexical semantics and syntactic impairments in left hemispheric strokes.