Poster E13, Thursday, August 22, 2019, 3:45 – 5:30 pm, Restaurant Hall
Language network re-organization associated with word- and sentence-level language interventions in chronic aphasia
Elena Barbieri1,2, James Higgins1,3, Kaitlyn Litcofsky1,2, Kathy Xie1,2, David Caplan1,4, Brenda Rapp1,5, Swathi Kiran1,6, Todd Parrish1,3, Cynthia Thompson1,2;1Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, 2Aphasia and Neurolinguistics Research Laboratory, Northwestern University, Evanston, 3Parrish Neuroimaging Laboratory, Northwestern University, Chicago, 4Neuropsychology Laboratory, Massachusetts General Hospital, Harvard Medical School, 5Cognitive and Brain Sciences Laboratory, Johns Hopkins University, 6Aphasia Research Laboratory, Boston University
Studies investigating the effects of language intervention on the re-organization of language networks in chronic aphasia have resulted in mixed findings, likely related to – among other factors – the language function targeted during treatment and the language task used to elicit brain activation [1]. Most studies have focused on naming, reporting greater activation (post- vs. pre-treatment) within intact regions in the left hemisphere (LH); however, studies have also found recruitment of regions in the right hemisphere (RH), positively correlated with treatment outcome [2]. The present study investigated the effects of the type of treatment provided for patients with chronic aphasia on neural activation using an auditory story comprehension task that in healthy participants reliably recruits a left fronto-temporo-parietal network [3]. We hypothesized that behavioral improvements associated with sentence processing, but not naming or spelling, treatments would result in shifts in activation using this task. Eighty-five individuals with chronic LH stroke-induced aphasia, recruited from three research laboratories (Northwestern University, NU; Boston University, BU; Johns Hopkins University, JHU) were assigned to either a language treatment (N=61) or control group (N=24). Participants in the treatment group received approximately 12-weeks of language treatment targeting one of three language domains: sentence comprehension/production (NU), naming (BU) or spelling (JHU). At baseline and post-testing, participants in both groups underwent language testing and performed an fMRI story comprehension task, which included alternating blocks of auditorily-presented short stories and a control condition (reversed speech) and required participants to listen to the stories and answer comprehension questions. At all recruitment sites, participants in the treatment, but not control, group evinced significant behavioral gains in the treated language domains. Region-of-Interest analyses of the fMRI story comprehension data revealed a significant increase in activation from pre- to post-treatment for the NU treatment group, but no changes in activation were found in the BU or JHU treatment groups, or in the control group. Results for the NU treatment group showed post-treatment upregulation of regions within the language network and were restricted to the RH. When overlaid onto activation maps derived from a group of healthy individuals performing the same task, post-treatment activation maps for the NU treatment group showed post- (vs. pre-treatment) recruitment of RH regions that were either active (i.e., posterior middle temporal gyrus, inferior frontal gyrus) or homologous to active LH regions (i.e., superior frontal, precentral gyri) in healthy individuals. Increased activation was positively correlated with behavioral change (i.e., verb comprehension), derived from a Principle Component Analysis of the behavioral data. These findings indicate that the language domain targeted for treatment affects re-organization of the language network. Sentence-level language intervention impacted comprehension of naturalistic narrative language and recruited regions with the normal language network in the RH, whereas (spoken or written) word-level treatments did not, indicating that treatment that exploits specific language processes impacts brain mechanisms associated with those process. 1. Kiran, S., & Thompson, C.K. (2019). Frontiers in Neurology, 10. 2. Barbieri, E., et al. (under revision). Cortex. 3. Wilson, S. M., et al. (2007). Cerebral cortex, 18(1), 230-242.
Themes: Disorders: Acquired, Language Therapy
Method: Functional Imaging