Thinking for speaking and thinking for listening: The interaction of thought and language in typical and non-fluent comprehension and production

Creating a Theoretical Framework to Underpin Discourse Assessment and Intervention in Aphasia

Discourse (a unit of language longer than a single sentence) is fundamental to everyday communication. People with aphasia (a language impairment occurring most frequently after stroke, or other brain damage) have communication difficulties which lead to less complete, less coherent, and less complex discourse. Although there are multiple reviews of discourse assessment and an emerging evidence base for discourse intervention, there is no unified theoretical framework to underpin this research. Instead, disparate theories are recruited to explain different aspects of discourse impairment, or symptoms are reported without a hypothesis about the cause. What is needed is a theoretical framework that would clarify the specific linguistic skills that create completeness, coherence, and complexity (i.e., richness) in discourse, and illuminate both the processes involved in discourse production and the reasons for breakdown. This paper reports a review and synthesis of the theoretical literature relevant to spoken discourse in aphasia discourse, and we propose a novel theoretical framework which unites these disparate sources. This framework is currently being tested as the foundation for Linguistic Underpinnings of Narrative in Aphasia (LUNA) treatment research. In this paper, we outline the novel framework and exemplify how it might be used to guide clinical practice and research. Future collaborative research is needed to develop this framework into a processing model for spoken discourse.

Temporal and Episodic Analyses of the Story of Cinderella in Latent Aphasia

Purpose The purpose of this study was to improve our understanding of the language characteristics of people with latent aphasia using measures that examined temporal (i.e., real-time) and episodic organization of discourse production. Method Thirty AphasiaBank participants were included (10 people with latent aphasia, 10 people with anomic aphasia, and 10 neurotypical control participants). Speech material of Cinderella narratives was analyzed with Praat software. We devised a protocol that coded the presence and duration of all speech segments, dysfluencies such as silent and filled pauses, and other speech behaviors. Using these durations, we generated a range of temporal measures such as speech, articulation, and pure word rates. Narratives were also coded into episodes, which provided information about the discourse macrostructure abilities of the participants. Results The latent aphasia group differed from controls in number of words produced, silent pause duration, and speech rate, but not articulation rate or pure word rate. Episodic organization of the narratives was similar in these 2 groups. The latent and anomic aphasia groups were similar in most measures, apart from articulation rate, which was lower in the anomic group. The anomic aphasia group also omitted more episodes than the latent aphasia group. Conclusions The differences between latent aphasia and neurotypical controls can be attributed to a processing speed deficit. We propose that this deficit results in an impaired ability to process information from multiple cognitive domains simultaneously.

Treatment for spoken and written word retrieval in the semantic variant of primary progressive aphasia

This study investigated whether a treatment programme for spoken word retrieval, supplemented with written naming, was beneficial for an individual with right-hemisphere dominant semantic variant of PPA (svPPA). Assessment and treatment were delivered remotely through Skype. Treatment consisted of two phases of lexical retrieval therapy (Repetition and Reading in the Presence of a Picture: RRIPP), with and without written responses (Phases 1 and 2 respectively), and a third treatment phase based on the procedures of Conceptual Enrichment (COEN) therapy. The first two phases of treatment resulted in short-lasting improvements in spoken and written word retrieval, with greater improvement in Phase 2 when written production was also required. Both treatment phases resulted in gains only for treated items, but generalised to different depictions to those treated. However, Phase 2 also resulted in significant improvement of treated items on a comprehension task. COEN treatment did not result in significant gains in word retrieval or comprehension. This study reinforces the value of a simple lexical retrieval treatment delivered remotely. It adds to the current evidence that anomia in svPPA can be responsive to treatment, but also shows that challenges remain regarding maintenance effects and the generalisation of treatment effects to connected speech.

Reviewing the quality of discourse information measures in aphasia

BACKGROUND

Discourse is fundamental to everyday communication, and is an increasing focus of clinical assessment, intervention and research. Aphasia can affect the information a speaker communicates in discourse. Little is known about the psychometrics of the tools for measuring information in discourse, which means it is unclear whether these measures are of sufficient quality to be used as clinical outcome measures or diagnostic tools.

AIMS

To profile the measures used to describe information in aphasic discourse, and to assess the quality of these measures against standard psychometric criteria.

METHODS & PROCEDURES

A scoping review method was employed. Studies were identified using a systematic search of Scopus, Medline and Embase databases. Standard psychometric criteria were used to evaluate the measures' psychometric properties.

MAIN CONTRIBUTION

The current review summarizes and collates the information measures used to describe aphasic discourse, and evaluates their quality in terms of the psychometric properties of acceptability, reliability and validity. Seventy-six studies described 58 discourse information measures, with a mean of 2.28 measures used per study (SD = 1.29, range = 1-7). Measures were classified as 'functional' measures (n = 33), which focused on discourse macrostructure, and 'functional and structural' measures (n = 25), which focused on micro-linguistic and macro-structural approaches to discourse. There were no reports of the acceptability of data generated by the measures (distribution of scores, missing data). Test-retest reliability was reported for just 8/58 measures with 3/8 > 0.80. Intra-rater reliability was reported for 9/58 measures and in all cases percentage agreement was reported rather than reliability. Per cent agreement was also frequently reported for inter-rater reliability, with only 4/76 studies reporting reliability statistics for 12/58 measures; this was generally high (>.80 for 11/12 measures). The majority of measures related clearly to the discourse production model indicating content validity. A total of 36/58 measures were used to make 41 comparisons between participants with aphasia (PWA) and neurologically healthy participants (NHP), with 31/41 comparisons showing a difference between the groups. Four comparisons were made between discourse genres, with two measures showing a difference between genres, and two measures showing no difference.

CONCLUSIONS

There is currently insufficient information available to justify the use of discourse information measures as sole diagnostic or outcome measurement tools. Yet the majority of measures are rooted in relevant theory, and there is emerging evidence regarding their psychometric properties. There is significant scope for further psychometric strengthening of discourse information measurement tools.

Cognitive grammar and aphasic discourse

In cognitive grammar (CG), there is no clear division between language and other cognitive processes; all linguistic form is conceptually meaningful. In this pilot study, a CG approach was applied to investigate whether people with aphasia (PWA) have cognitive linguistic difficulty not predicted from traditional, componential models of aphasia. Narrative samples from 22 PWA (6 fluent, 16 non-fluent) were compared with samples from 10 participants without aphasia. Between-group differences were tested statistically. PWA had significant difficulty with temporal sequencing, suggesting problems that are not uniquely linguistic. For some, these problems were doubly dissociated with naming, used as a general measure of severity, which indicates that cognitive linguistic difficulties are not linked with more widespread brain damage. Further investigation may lead to a richer account of aphasia in line with contemporary linguistics and cognitive science approaches.