Recovered vs. not-recovered from post-stroke aphasia: the contributions from the dominant and non-dominant hemispheres.

Academic Article

Abstract

  • PURPOSE: Several adult studies have documented the importance of the peri-stroke areas to aphasia recovery. But, studies examining the differences in patterns of cortical participation in language comprehension in patients who have (LMCA-R) or have not recovered (LMCA-NR) from left middle cerebral artery infarction have not been performed up to date. METHODS: In this study, we compare cortical correlates of language comprehension using fMRI and semantic decision/tone decision task in 9 LMCA-R and 18 LMCA-NR patients matched at the time of stroke for age and handedness. We examine the cortical correlates of language performance by correlating intra- and extra-scanner measures of linguistic performance with fMRI activation and stroke volumes. RESULTS: Our analyses show that LMCA-R at least 1 year after stroke show a return to typical fMRI language activation patterns and that there is a compensatory reorganization of language function in LMCA-NR patients with shifts to the right hemispheric brain regions. Further, with increasing strength of the left-hemispheric fMRI signal shift there are associated improvements in performance as tested with standardized linguistic measures. A negative correlation between the size of the stroke and performance on some of the linguistic tests is also observed. CONCLUSIONS: This right-hemispheric shift as a mechanism of post-stroke recovery in adults appears to be an ineffective mode of language function recovery with increasing right-hemispheric shift associated with lower language performance. Thus, normalization of the post-stroke language activation patterns is needed for better language performance while shifts of the activation patterns to the non-dominant (right) hemisphere and/or large stroke size are associated with decreased linguistic abilities after stroke.
  • Keywords

  • Adult, Aged, Aphasia, Brain, Comprehension, Dominance, Cerebral, Female, Humans, Image Processing, Computer-Assisted, Language Tests, Magnetic Resonance Imaging, Male, Middle Aged, Oxygen, Recovery of Function, Semantics, Stroke
  • Digital Object Identifier (doi)

    Author List

  • Szaflarski JP; Allendorfer JB; Banks C; Vannest J; Holland SK
  • Start Page

  • 347
  • End Page

  • 360
  • Volume

  • 31
  • Issue

  • 4