Determining stability in connected speech in primary progressive aphasia and Alzheimer’s disease

Abstract

Purpose: Using connected speech to assess progressive language disorders is confounded by uncertainty around whether connected speech is stable over successive sampling, and therefore representative of an individual’s performance, and whether some contexts and/or language behaviours show greater stability than others.

Method: A repeated measure, within groups, research design was used to investigate stability of a range of behaviours in the connected speech of six individuals with primary progressive aphasia and three individuals with Alzheimer’s disease. Stability was evaluated, at a group and individual level, across three samples, collected over 3 weeks, involving everyday monologue, narrative and picture description, and analysed for lexical content, fluency and communicative informativeness and efficiency.

Result: Excellent and significant stability was found on the majority of measures, at a group and individual level, across all genres, with isolated measures (e.g. nouns use, communicative efficiency) showing good, but greater variability, within one of the three genres.

Conclusion: Findings provide evidence of stability on measures of lexical content, fluency and communicative informativeness and efficiency. While preliminary evidence suggests that task selection is influential when considering stability of particular connected speech measures, replication over a larger sample is necessary to reproduce findings.

Keywords:

• Primary progressive aphasia
• Alzheimer’s disease
• connected speech
• stability
• elicitation genres and tasks

Acknowledgements

We would like to thank all of the participants who took part in this research. We would also like to thank speech-language pathology students, Daphlyn Goh and Sallina Le, for their work on this project.

Declaration of interest

The authors report no declarations of interest.

This work was supported by the Dementia Australia Research Foundation and Curtin University through the Australian Government Research Training Program.

Supplementary material

Supplemental data for this article can be accessed at https://doi.org/10.1080/17549507.2018.1442498.

Additional information

Funding

This work was supported by the Alzheimer’s Australia Dementia Research Foundation and Curtin University under the CDRN Half-Funded PhD Scholarship.