Analysing syntactic productions in semantic variant PPA and non-fluent variant PPA: how different are they?

ABSTRACT

Background: It is commonly held that individuals with the non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA) show difficulties with syntactic production, but that the production of individuals with the semantic variant of primary progressive aphasia (svPPA) is intact. Much of this evidence to date is derived from results of unconstrained language production tasks. There is emerging evidence however that the syntactic production of individuals with svPPA may not be as accurate as was previously thought.

Aims: The goal of the current study was to investigate the sentence production abilities of participants with nfvPPA and svPPA (in comparison to matched control participants) using a constrained task eliciting syntactically complex utterances.

Methods & Procedures: A constrained picture description task, which elicited active, passive, dative, and dative–passive sentences, was administered to three groups of participants (individuals with nfvPPA and svPPA and matched controls) on up to three occasions over a span of 2 years. Responses were scored and analysed using analyses of variance, crossing group and sentence type, for each of the testing times.

Outcomes & Results: Results show that both the nfvPPA and svPPA groups demonstrated more difficulty with the passive and dative–passive structures compared to the active and dative sentence structures and compared to control participants, although the difficulties were more severe and were observed earlier for the participants with nfvPPA. Both groups also demonstrated difficulty with noun production, although in this case the difficulty was more severe for the participants with svPPA.

Conclusions: The current group study provides new evidence of a syntactic production difficulty in individuals with svPPA, notably when complex structures are elicited. The source of the difficulty, whether it is due to a primary syntactic impairment and/or as an extension of the impairment to their semantic system, remains unclear. However, the impairment appears to differ from that of participants with nfvPPA. Further clarification of this syntactic production impairment can yield potentially useful information for researchers and clinicians in this field.

KEYWORDS:

• Syntactic production
• semantic variant primary progressive aphasia
• non-fluent variant primary progressive aphasia

Acknowledgements

Canadian Institutes of Health Research (CIHR) [grant numbers 82744; 130462]; Canadian Institutes of Health Research (CIHR); Post-doctoral fellowship (J.C.); Department of Medicine at the University of Toronto and Sunnybrook Health Sciences Center, the Brill Chair in Neurology, the Brain Sciences Research Program, and Sunnybrook Research Institute (S.E.B.). The authors thank two anonymous reviewers for helpful comments and ideas in interpretation of the data. The authors would also like to thank Inderjit Sohal, Amy Lewis, Shayna Sparling, Danna Rybko, and Ashleigh Wishen for help with testing subjects.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. Subject–object relative sentences were not elicited in the current study due to the difficulty demonstrated by control subjects with this syntactic structure in Caplan and Hanna’s (1998) original article.

Additional information

Funding

This work was supported by Canadian Institutes of Health Research (CIHR) [grant numbers 82744; 130462]; Canadian Institutes of Health Research (CIHR); Post-doctoral fellowship (J.C.); Department of Medicine at the University of Toronto and Sunnybrook Health Sciences Center, the Brill Chair in Neurology, the Brain Sciences Research Program, and Sunnybrook Research Institute (S.E.B.).