Neural Basis of Language in Acute Stroke and Recovery

Language deficits after stroke resolve to different degrees across individuals. In previous funding cycles we have characterized distinct mechanisms of recovery, including restoration of blood flow to dysfunctional brain tissue surrounding the infarct and reorganization of networks (brain regions or their connections) underlying specific language functions. We have previously focused on mechanisms of recovery of naming and spoken word comprehension. Here we propose to characterize mechanisms of recovery of discourse comprehension, reading, and spelling (functions that are increasingly critical in a society dependent on internet use such as online banking and shopping, email, texting, and so on) in each individual with aphasia over the course of one year. In addition, we will evaluate the use of compensation by learning to accomplish the function in a different way or using different modalities to communicate, as another mechanism of recovery. We will use longitudinal structural and perfusion imaging, along with functional Near Infrared Spectroscopy (fNIRS) and language assessments twice within 10 days of stroke onset (once before and once after intervention to restore blood flow or 3 days after initial testing in cases of no intervention) and again at 3 months, 6 months, and 12 months after acute left hemisphere ischemic stroke. Furthermore, we propose to identify variables that predict recovery through each mechanism. We will determine which demographic, imaging, and genetic factors influence the success of each mechanism. Results will allow clinicians to focus treatment strategies on the mechanisms most likely to be successful for an individual. Thus, the brain imaging and behavioral data together will help us achieve another important clinical goal, aligned with the mission of NIDCD, to improve prognosis for aphasia recovery at an individual level. Identifying lesion and brain health characteristics, polymorphisms of the Brain Derived Neurotrophic Factor allele, selective serotonin receptor antagonists (SSRIs), demographic factors, pre-stroke written language use information, and use of compensatory strategies that independently contribute to aphasia recovery will allow us to better predict who is likely to achieve the greatest recovery and under what conditions. These results will also provide the critical basis for individualized aphasia rehabilitation. We will test our hypotheses in a racially and socioeconomically diverse population of people with post-stroke aphasia, which is essential to allow generalization of findings to improve management of a wide range of people with aphasia (PWA).