Many types of brain injuries, particularly stroke, can result in serious language impairment. Many veterans with aphasia have some degree of difficulty understanding language when they are spoken to, which affects their ability to communicate. Some recover their auditory comprehension skills over time, while some do not. To date, there is no clear-cut explanation as to why this occurs, making it difficult for clinicians to offer a concrete prognosis to their patiets and family members as to the degree of language recovery that can be expected. The proposed study will examine the neural factors associated with recovery from auditory comprehension impairment. Novel neuroimaging techniques will examine the brain structures that affect recovery, particularly the fiber pathways that connect cortical regions to each other. Damage to these fiber tracts will be assessed with the latest in diffusion imaging to visualize and quantify the damage in individual tracts. 45 veteran aphasic patients with auditory comprehension deficits will be assessed at 1 and 12 months post- onset of their stroke to track the degree of comprehension impairment and the course of its recovery. Structural magnetic resonance imaging (MRI) will also be performed at 1 and 12 months post-onset to assess the extent of the damage to cortical areas and whether this damage can predict recovery. High angular resolution diffusion imaging (HARDI), also obtained at the same time intervals, will quantify the extent of the damage to individual white matter pathways, while tractography will provide visual confirmation of each fiber tract in each patient. Finally, white matter integrity will be measured t 1 and 12 months to assess the changes that occur in fiber pathways during the recovery period. The proposed project will examine several aspects of recovery that have not been fully explored. With our expertise in aphasia and neuroimaging and our success in using HARDI tractography to characterize the full extent of the damage in white matter pathways, we are in a unique position to carry out this innovative research. This project will yield information that can directly influence patient care; clinicians will have more accurate information with which to guide their treatment approach, and better inform veterans and caregivers as to how to plan their futures.
Brain injury is very common in our veteran patients and one of its unfortunate consequences is the disruption of speech and language skills (aphasia) that affect how people can communicate. Most individuals with aphasia have difficulty understanding what others say to them, ranging from trouble understanding a few sentences to a more severe problem where even simple phrases are not understood. Some people recover very well from this disorder, while others do not, and the reason why is unclear. The proposed study will use state-of-the-art brain imaging tools to examine the underlying brain structures important for recovery of language comprehension. We will also focus on the fiber pathways that connect these brain regions to one another, as we have found them to be critical for supporting speech and language functions and expect them to play a key role in recovery, as well. Information resulting from this study will provide clinicians with the information they need to give our veteran patients the most accurate diagnosis, prognosis, and effective treatment to date.
