The Accuracy-Fluency Trade-off in Non-Fluent Aphasia

EasyChair Preprint 6535

Abstract

Agrammatic utterances have traditionally been characterized by their reduced morpho-syntactic complexity. Besides, fluency disturbances – including pauses, false starts, self-corrections, abusive use of fillers and pragmatic operators, repetitions, revisions – are frequent, thus making speech production visibly effortful. Results from previous corpus analyses confirm that variability in agrammatic performance is a key feature for understanding not only the underlying impairment, but also the strategic language use (Kolk & Heeschen, 1990; Sahraoui & Nespoulous, 2012). Across-task variability is a result of the use of differential adaptation strategies related to the amount of focus on form, which may enable a better grammatical accuracy under certain conditions. Based on this observation, we hypothesize that agrammatic speakers may over-use monitoring skills in language production at a pre- or post-articulatory stage and that this monitoring can make fluency vary in function of the type of task. To understand how speech (non)fluency interacts with morpho-syntactic well-formedness, we looked at a corpus from 5 agrammatic and 9 control speakers in different tasks : spontaneous speech, narrative, picture description and sentence production. Results show less dysfluencies and revisions in free speech compared to picture description and targeted sentence production. We thus conclude that task-sensitive accuracy and fluency is also due to the intervention of pre- or post-articulatory speech monitoring and executive functions, leading to trade-offs between fluency and grammatical accuracy in support of the adaptation theory.

References

Kolk, H. H. J. & Heeschen, C. (1990). Adaptation and impairment symptoms in Broca's aphasia. Aphasiology, 4(3), 221-231.

Sahraoui, H. & Nespoulous, J‐L. (2012). Across‐task variability in agrammatic performance. Aphasiology, 26(6), 785-810.

Keyphrases: Accuracy, adaptation, agrammatic aphasia, fluency, monitoring, post-articulatory, pre-articulatory

@booklet{EasyChair:6535,
  author    = {Halima Sahraoui and Silvia Martìnez-Ferreiro},
  title     = {The Accuracy-Fluency Trade-off in Non-Fluent Aphasia},
  howpublished = {EasyChair Preprint 6535},
  year      = {EasyChair, 2021}}