A Lesion-Symptom Mapping Study of Syntactic Acceptability Judgments in Chronic Post-Stroke Aphasia

EasyChair Preprint no. 6601

Abstract

Classically, expressive agrammatism has been correlated nonfluent Broca’s aphasia with frontal damage in lesion-symptom mapping (LSM) studies of people with stroke-based aphasia (PWA). Syntactic comprehension deficits have also been associated with Broca’s aphasia. However, some LSM studies have identified the posterior temporal and inferior parietal lobes in people with fluent aphasia, while others have associated damage to frontal networks with deficits in comprehension of non-canonical sentences. To test whether frontal pr posterior damage results in syntactic comprehension deficits, we performed LSM study using syntactic acceptability judgments, which assesses sentences' well-formedness rather than judging meaning. We predicted PWA would better detect word-order violation than agreement or subcategorization violations, and LSM to show an association between posterior temporal damage and comprehension deficits, but not frontal damage. To do this, we adapted an acceptability judgement task in two experiments using correct and matched ungrammatical sentences. We performed ANOVAs to identify differential accuracy by group (PWA v. age-match controls), violation type & sentence location. We also performed LSM analyses. 22 PWA and 16 controls have participated. PWA performed poorer in each category; ANOVA results for PWA showed effects of error type and location and an interaction between error type and location. Participants were more accurate on word-order violations, but unexpectedly more accurate on subcategorization violations than agreement violations. LSM analyses showed a significant association to a posterior temporal ROI but not an inferior frontal ROI consisting of Broca’s area. Our results speak against the hypotheses that frontal regions support syntactic comprehension, and support previous associations of syntactic comprehension deficits with damage to the posterior temporal lobe.

Keyphrases: aphasia, syntactic acceptability judgement task, syntactic processing

@Booklet{EasyChair:6601,
  author = {Danielle Fahey and Julia Igoe and Julius Fridriksson and Gregory Hickok and William Matchin},
  title = {A Lesion-Symptom Mapping Study of Syntactic Acceptability Judgments in Chronic Post-Stroke Aphasia},
  howpublished = {EasyChair Preprint no. 6601},

  year = {EasyChair, 2021}}