Speed–Accuracy Trade-Offs and Adaptation Deficits in Aphasia: Finding the “Sweet Spot” Between Overly Cautious and Incautious Responding Purpose After stroke, how well do people with aphasia (PWA) adapt to the altered functioning of their language system? When completing a language-dependent task, how well do PWA balance speed and accuracy when the goal is to respond both as quickly and accurately as possible? The current work investigates adaptation ... Research Article
Newly Published
Research Article  |   September 12, 2018
Speed–Accuracy Trade-Offs and Adaptation Deficits in Aphasia: Finding the “Sweet Spot” Between Overly Cautious and Incautious Responding
 
Author Affiliations & Notes
  • William S. Evans
    Department of Communication Sciences and Disorders, University of Pittsburgh, PA
    Geriatric Research Education and Clinical Center, VA Healthcare System, Pittsburgh, PA
  • William D. Hula
    Department of Communication Sciences and Disorders, University of Pittsburgh, PA
    Geriatric Research Education and Clinical Center, VA Healthcare System, Pittsburgh, PA
  • Jeffrey J. Starns
    Department of Psychology, University of Massachusetts, Amherst
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to William S. Evans: wie6@pitt.edu
  • Editor-in-Chief: Julie Barkmeier-Kraemer
    Editor-in-Chief: Julie Barkmeier-Kraemer×
  • Editor: Christos Salis
    Editor: Christos Salis×
  • Publisher Note: This article is part of the Special Issue: Select Papers From the 47th Clinical Aphasiology Conference.
    Publisher Note: This article is part of the Special Issue: Select Papers From the 47th Clinical Aphasiology Conference.×
Article Information
Normal Language Processing / Language Disorders / Aphasia / Newly Published / Research Article
Research Article   |   September 12, 2018
Speed–Accuracy Trade-Offs and Adaptation Deficits in Aphasia: Finding the “Sweet Spot” Between Overly Cautious and Incautious Responding
American Journal of Speech-Language Pathology, Newly Published. doi:10.1044/2018_AJSLP-17-0156
History: Received September 15, 2017 , Revised March 8, 2018 , Accepted April 26, 2018
 
American Journal of Speech-Language Pathology, Newly Published. doi:10.1044/2018_AJSLP-17-0156
History: Received September 15, 2017; Revised March 8, 2018; Accepted April 26, 2018

Purpose After stroke, how well do people with aphasia (PWA) adapt to the altered functioning of their language system? When completing a language-dependent task, how well do PWA balance speed and accuracy when the goal is to respond both as quickly and accurately as possible? The current work investigates adaptation theory (Kolk & Heeschen, 1990) in the context of speed–accuracy trade-offs in a lexical decision task. PWA were predicted to set less beneficial speed–accuracy trade-offs than matched controls, and at least some PWA were predicted to present with adaptation deficits, with impaired accuracy or response times attributable to speed–accuracy trade-offs.

Method The study used the diffusion model (Ratcliff, 1978), a computational model of response time for simple 2-choice tasks. Parameters of the model can be used to distinguish basic processing efficiency from the overall level of caution in setting response thresholds and were used here to characterize speed–accuracy trade-offs in 20 PWA and matched controls during a lexical decision task.

Results Models showed that PWA and matched control groups did not differ overall in how they set response thresholds for speed–accuracy trade-offs. However, case series analyses showed that 40% of the PWA group displayed the predicted adaptation deficits, with impaired accuracy or response time performance directly attributable to overly cautious or overly incautious response thresholds.

Conclusions Maladaptive speed–accuracy trade-offs appear to be present in some PWA during lexical decision, leading to adaptation deficits in performance. These adaptation deficits are potentially treatable, and clinical implications and next steps for translational research are discussed.

Acknowledgments
This research was funded by the National Institute of Health (NIDCD-F31DC013489, awarded to William S. Evans), the Boston University Dudley Allen Sargent Research Fund, the VA Pittsburgh Healthcare System Geriatric Research Education and Clinical Center, and the VA RR&D service (IK1 RX002475, awarded to William S. Evans). Sincere thanks to the first author's doctoral committee (David Caplan, Gloria Waters, Randi Martin, and Jeff Starns), to colleagues at the VA Pittsburgh Geriatric Research Education and Clinical Center for helpful feedback, and to Adam Ostrowski and Stacey Kellough for statistics and programming support.
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