title: Role for Memory Capacity in Sentence Comprehension: Evidence from Acute Stroke.
abstract: BACKGROUND
  Previous research has suggested that short-term and working memory resources play a critical role in sentence comprehension, especially when comprehension mechanisms cannot rely on semantics alone. However, few studies have examined this association in participants in acute stroke, before the opportunity for therapy and reorganization of cognitive functions.
  
  
  OBJECTIVE
  The present study examined the hypothesis that severity of short-term memory deficit due to acute stroke predicts the severity of impairment in the comprehension of syntactically complex sentences. Furthermore, we examined the association between damage to the short-term and working memory network and impaired sentence comprehension, as an association would be predicted by the previous hypothesis.
  
  
  METHODS
  47 participants with acute stroke and 14 participants with a transient ischemic attack (TIA; the control group) were included in the present study. Participants received a language battery and clinical or research scans within 48 hours of hospital admittance. The present study focused on the behavioral data from the short-term memory and working memory span tasks and a sentence-picture matching comprehension task included in this battery. Using regression analyses, we examined whether short-term and working memory measures explained significant variance in sentence comprehension performance.
  
  
  RESULTS
  Consistent with prior research, short-term memory explained significant variance in sentence comprehension performance in acute stroke; in contrast, working memory accounted for little variance beyond that which was already explained by short-term memory. Furthermore, ischemia that included the short-term/working memory network was sufficient to cause sentence comprehension impairments for syntactically complex sentences.
  
  
  CONCLUSIONS
  The present study suggests that short-term memory resources are an important source of sentence comprehension impairments.
authors.affiliation: Department of Neurology, Division of Cognitive Neuroscience Johns Hopkins University School of Medicine 1620 McElderry Street Baltimore, MD, 21205.
authors.forename: Corinne
authors.initials: C
authors.lastname: Pettigrew
authors.affiliation: Department of Neurology Johns Hopkins University School of Medicine 600 North Wolfe Street Baltimore, MD 21287 (410) 614-2381 argye@jhmi.edu.
authors.forename: Argye E
authors.initials: AE
authors.lastname: Hillis
keywords: acute stroke; sentence comprehension; short-term memory; working memory