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Neural correlates of connected speech outcomes and recovery from aphasia in the first year after stroke
Poster Session D, Saturday, October 26, 10:30 am - 12:00 pm, Great Hall 3 and 4
Marianne Casilio1, Anna V Kasdan1, Sarah M Schneck1, Jillian Entrup1, Lily Walljasper1, Caitlin Onuscheck1, Deborah Levy1, Michael de Riesthal1, Stephen M Wilson1,2; 1Vanderbilt University Medical Center, 2University of Queensland
Acute lesion characteristics are the most explanatory predictors of overall aphasia outcomes and recovery after stroke[1]—yet these lesion predictors remain “elusive”[2], in part because their relevance to language produced in everyday contexts (connected speech) is largely unknown. The present study characterized the neural correlates of connected speech outcomes and recovery from aphasia in the first year after stroke. Leveraging a large longitudinal study[1], we extracted connected speech samples from 195 patients diagnosed acutely with aphasia following left-hemisphere stroke; individuals were tested at four timepoints (2–5 days, 1 month, 3 months, 12 months post-onset). Samples were scored by a speech-language pathologist blinded to other data using the Auditory-Perceptual Rating of Connected Speech in Aphasia (APROCSA)[3,4], a validated assessment approach that yields scores on four dimensions: Paraphasia (misselection of words/sounds), Logopenia (paucity of words), Agrammatism (morphosyntactic omissions), and Motor speech (impaired speech motor programming/execution). Acute clinical neuroimaging was also acquired, and lesions were delineated using established methods[1]. For each individual, we computed the volume of damage in three left-hemisphere regions of interest (ROIs) within the language network (Prefrontal, Frontoparietal, Temporal)[5] and a fourth non-language region (Other). Data were analyzed using growth curve modeling. To evaluate the effect of acute lesion characteristics on outcomes, repeated measures of the four APROCSA dimension scores were expressed as a function of a random effect for participants, a fixed effect for time post-onset, and a fixed effect for all four ROIs. To evaluate the effect of acute lesion characteristics on recovery (rate of change on dimension scores), time-by-ROI interactions were added. The neural correlates of outcomes in the first year after stroke were nearly identical to those observed acutely[4]. Paraphasia was associated exclusively with damage to the Temporal ROI (p<.001) while Logopenia was associated exclusively with damage to the Frontoparietal ROI (p=.003). Agrammatism was associated with damage to both the Frontoparietal (p=.004) and Other (p=.03) ROIs. Motor speech was associated with damage to the Frontoparietal ROI (p<.001). The neural correlates of recovery diverged from those observed acutely[4] and over the long-term. Rate of change on most dimension scores depended on a diminishing effect of the Prefrontal (Logopenia: p=.047) or Frontoparietal (Agrammatism: p=.005; Motor speech: p=.037) ROIs; damage to these regions mattered less as time post-stroke increased. Remarkably, there was no effect of the Temporal ROI; damage to this region had persistent effects across time. Additionally, there was an increasing effect of the Other ROI on Agrammatism (p=.003), along with marginal effects on the other three dimensions; damage to this region mattered more as time post-stroke increased. Collectively, these findings confirm the importance of acute lesion characteristics, reveal the differential capacity of frontal versus temporal language regions to reorganize[6], and suggest a potential role for brain regions outside the canonical language network in the recovery of language produced in context. [1]Wilson et al. Brain. 2023;146(3):1021-39. [2]Ali et al. Aphasiology. 2022;36(4):555-574. [3]Casilio et al. Am J Speech Lang Pathol. 2019;28(2):550-568. [4]Casilio et al. Brain. 2024; in press. [5]Yen et al. NeuroImage. 2019;189:368-379. [6]Stockert et al. Brain. 2020;143(3):844-861.
Topic Areas: Disorders: Acquired, Language Production