(Dis)fluency markers in dementia: how much can errors tell us?
-
1
University of Barcelona, Department of Catalan and General Linguistics, Spain
-
2
Hospital General de Hospitalet de Llobregat, Neurology Service, Spain
Background: Fluency is both a diagnostic criterion and a clinical label inherited by the field of dementia from cerebrovascular aphasia. As the multidimensional entity it is it has no clear working definition for diagnosis since its different components can be traced back to distinct functional networks and brain areas. For instance, the former nonfluent variant of Primary Progressive Aphasia (PPA) now subsumes the agrammatic/nonfluent (PPA-nf) and the logopenic (PPA-L) subtypes. While the former is in need of redefinition after the discovery of Primary Progressive Apraxia and the persisting difficulties in describing frank agrammatism, the latter has been questioned due to its pathological link to Alzheimer’s Dementia (AD), a condition that also exhibits linguistic deficits (Leyton & Ballard, 2016). Mild Cognitive Impairment (MCI) - especially its multifocal type- also displays linguistic impairments and has been linked to dementia, especially the temporomesial type with AD. Given its clinical heterogeneity the identification of differential profiles could be key for the early diagnosis of specific dementia aetiologies. However, speech production and fluency measures seem to offer low test-retest reliability in these populations, especially in short speech samples (Ahmed, Haigh, de Jager & Garrard, 2013), raising doubts about their diagnostic and descriptive value even in the face of perceived disfluency and/or incipient communicative impairment.
Procedure: Samples of picture-based oral narratives by Spanish-speaking participants were transcribed using multi-layer annotation accounting for different language levels with an ad-hoc system for disfluency labelling and pause distribution reporting. The cohort included 13 mildly-impaired AD patients, 15 amnestic-temporomesial(aMCIa) and 24 amnestic-executive (aMCIb) MCI subjects, as well as 4 PPA-nf and 10 PPA-L patients in the mild to moderate stages, and 11 healthy elderly controls (HC). The occurrence of false starts, repetitions, repaired sequences, abandoned structures, automatisms, perseverations and echolalia as well as intra-clausal and intra-phrasal pauses was evaluated and compared to other linguistic measures in order to find differential performance patterns.
Results: Compared to HC and aMCIb subjects APP-nf participants exhibited the classic disfluent pattern with a significant disfluency rate, particularly in repetition and false start counts, combined with a greater number of intra-clausal pauses and less correct words. APP-L individuals showed a disfluent pattern with repaired sequences, lexical and semantic paraphasias and phonological errors, in addition to an also significantly high intra-clausal pause rate. Participants with AD displayed a longer total silence time and more pauses, alongside a significant number of lexico-semantic paraphasias. aMCIa patients performed similarly but lexical and semantic errors were the only statistically significant parameters.
Conclusion: Disfluency markers proved more useful than classic measures for describing group performance and their correlations with linguistic indexes (fig.2) indeed seem to reveal differential (dis)fluency patterns that can be related to specific functional circuits. aMCIa subjects show incipient linguistic deficits in an almost comparable rate and distribution to those of AD participants, which could be pre-dementia signs related to early memory loss. This calls for a closer look into lexico-semantic and speech planning deficits as they could be linked to temporo-parietal damage in the early stages of pre-clinical dementia.
Acknowledgements
This work is partially supported by La Caixa Foundation through a PhD grant awarded to P.P.D.
References
Ahmed, S., Haigh, A.-M. F., de Jager, C. a, & Garrard, P. (2013). Connected speech as a marker of disease progression in autopsy-proven Alzheimer’s disease. Brain : A Journal of Neurology, 136(Pt 12), 3727–37.
Leyton, C. E., & Ballard, K. J. (2016). Primary progressive aphasia: conceptual evolution and challenges. Neuroscience and Neuroeconomics, 5, 9–18.
Keywords:
Alzheimer's dementia,
Mild Cognitive Impairment,
Language,
Narrative,
Speech,
logopenic primary progressive aphasia,
Primary Progressive Nonfluent Aphasia,
early diagnosis
Conference:
Academy of Aphasia 55th Annual Meeting , Baltimore, United States, 5 Nov - 7 Nov, 2017.
Presentation Type:
poster presentation
Topic:
Consider for student award
Citation:
Pastoriza-Domínguez
P,
Diéguez-Vide
F,
Gómez-Ruiz
MI,
Bello-López
J and
Águila-Rivera
A
(2019). (Dis)fluency markers in dementia: how much can errors tell us?.
Conference Abstract:
Academy of Aphasia 55th Annual Meeting .
doi: 10.3389/conf.fnhum.2017.223.00115
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
02 May 2017;
Published Online:
25 Jan 2019.
*
Correspondence:
Ms. Patricia Pastoriza-Domínguez, University of Barcelona, Department of Catalan and General Linguistics, Barcelona, Spain, p.pastoriza.dominguez@gmail.com