Neural Correlates of Recovery from Aphasia After Stroke

Project Summary/Abstract Aphasia is one of the most common and debilitating consequences of stroke. Fortunately, most individuals with aphasia experience some degree of recovery of speech and language function over time. However, there is great variability in terms of the extent of recovery, which has historically been poorly understood. The overall goals of this R01 program are (1) to describe the nature of recovery from aphasia in the first year after stroke; (2) to identify neuroimaging, behavioral, and patient-related predictors of recovery; and (3) to characterize the neural correlates of recovery using functional and structural imaging. In previous cycles, we have recruited 380 individuals with aphasia and built an unprecedented longitudinal dataset of speech/language evaluations and multi modal neuroimaging. We have comprehensively documented trajectories of recovery from aphasia and their dependence on lesion location and extent, shown that this information can be used to explain much of the variance in recovery patterns, and revealed the critical role of surviving core language regions in language processing in people with aphasia. In the present renewal application, we propose to address several remaining knowledge gaps and pursue opportunities for clinical translation. We will extend our ongoing longitudinal study of aphasia recovery, recruiting 240 new individuals with acute post-stroke aphasia over the next 4 years. We will use this expanded dataset to determine what functional changes underlie the robust recovery that we have observed, investigating two hypotheses: (1) that reorganization may be highly specific to individual patterns of brain damage and behavioral variables; and/or (2) that the neuroplastic changes supporting recovery may take place primarily within surviving language regions. In Aim 1, we will identify longitudinal changes in the functional organization of language regions associated with recovery from aphasia, using validated semantic and phonological adaptive language mapping paradigms, and models that incorporate information about both structural damage and behavior. In Aim 2, we will characterize longitudinal changes within surviving language regions in terms of their representational capacity, using a new naturalistic functional imaging paradigm and state-of-the-art language encoding models. Even as we continue to explore the mechanisms that support recovery, we are also ready to develop tools and resources to allow clinicians to make use of the information we have already gained. In Aim 3, we will translate our findings for real-world clinical applications by creating a fully automated aphasia recovery prediction tool and a multimodal data portal. Our project will inform ongoing research into behavioral and neuromodulatory interventions, and will support clinicians in developing realistic goals for rehabilitation, optimizing allocation of treatment resources, and providing individualized education to individuals with aphasia and their caregivers and families.