Morphosyntactic production and WM in aphasia (Fyndanis et al., 2018)

<div><b>Purpose:</b> The present work investigated whether verbal working memory (WM) affects morphosyntactic production in configurations that do not involve or favor similarity-based interference and whether WM interacts with verb-related morphosyntactic categories and/or cue–target distance (locality). It also explored whether the findings related to the questions above lend support to a recent account of agrammatic morphosyntactic production: Interpretable Features’ Impairment Hypothesis (Fyndanis, Varlokosta, & Tsapkini, 2012).</div><div><b>Method: </b>A sentence completion task testing production of subject–verb agreement, tense/time reference, and aspect in local and nonlocal conditions and two verbal WM tasks were administered to 8 Greek-speaking persons with agrammatic aphasia (PWA) and 103 healthy participants.</div><div><b>Results: </b>The 3 morphosyntactic categories dissociated in both groups (agreement > tense > aspect). A significant interaction emerged in both groups between the 3 morphosyntactic categories and WM. There was no main effect of locality in either of the 2 groups. At the individual level, all 8 PWA exhibited dissociations between agreement, tense, and aspect, and effects of locality were contradictory.</div><div><b>Conclusions: </b>Results suggest that individuals with WM limitations (both PWA and healthy older speakers) show dissociations between the production of verb-related morphosyntactic categories. WM affects performance shaping the pattern of morphosyntactic production (in Greek: subject–verb agreement > tense > aspect). The absence of an effect of locality suggests that executive capacities tapped by WM tasks are involved in morphosyntactic processing of demanding categories even when the cue is adjacent to the target. Results are consistent with the Interpretable Features’ Impairment Hypothesis (Fyndanis et al., 2012).</div><div><b><br></b></div><div><b>Supplemental Material S1.</b> Rating scale profile of speech characteristics. </div><div><b><br></b></div><div><b>Supplemental Material S2.</b> Residuals model on Dataset 1; fitted against observed model on Dataset 1. </div><div><br></div><div><b>Supplemental Material S3. </b>Dataset 1: Working memory (WM) capacity partial residuals. </div><div><br></div><div><b>Supplemental Material S4.</b> Residuals model on Dataset 2; fitted against observed model on Dataset 2. </div><div><br></div><div><b>Supplemental Material S5.</b> Dataset 2: Working memory (WM) capacity partial residuals. </div><div><br></div><div><b>Supplemental Material S6. </b>Dataset 2: Age partial residuals. </div><div><b><br></b></div><div><b>Supplemental Material S7. </b>Individual performance (correct) of healthy participants on subject–verb agreement, tense, and aspect (with local and nonlocal conditions collapsed).</div><div><br></div><div>Fyndanis, V., Arcara, G., Christidou, P., & Caplan, D. (2018). Morphosyntactic production and verbal working memory: Evidence from Greek aphasia and healthy aging. <i>Journal of Speech, Language, and Hearing Research, 61,</i> 1171–1187.</div>