Learning Beyond Criterion in Aphasia Rehabilitation

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DESCRIPTION (provided by applicant): Acquired reading disorders (alexias) are common in patients with aphasia subsequent to left hemisphere stroke or head injury. Even when language functions recover sufficiently to enable the patient to return to work, unrecovered alexia often significantly interferes with job performance. Patients who cannot return to work may be left with little to occupy their time; regaining the ability to read would make a significant improvement in their quality of life. An important factor affecting a patient's ability to return to work and sustain a good quality of life is successful therapy. A language therapy is generally considered to be effective if a patient succeeds in performing a set of tasks at a specific criterion level over a number of sessions. Attaining this goal is significant; it demonstrates that learning has occurred, provides the patient with a sense of progress, and advances our understanding of language processing in the brain. However, an essential component of rehabilitation that rarely receives sufficient attention is the patient's ability to maintain the learned skills after therapy is terminated. 1 goal of this project is to examine the effects of training beyond criterion performance upon the maintenance of learned language skills. A second goal is to investigate the functional changes in the brain that occur following successful treatment, and to explore any additional changes that may occur following such extended periods of additional practice. According to neuropsychological models of reading, the success of aphasia treatment in stroke patients is dependent upon the reorganization of the cognitive and neural pathways used to process language; thus, fMRI techniques may be useful in documenting and elucidating how changes in processing may be brought about by aphasia therapy and extended practice. The proposal focuses on treatment of 2 specific deficits: pure alexia and phonologic alexia. However, the principles being examined are general ones, and apply to aphasia therapies in general. Functional brain activation patterns during certain reading tasks will be measured prior to treatment for these alexic disorders, then again following completion of the treatment (as ascertained by the reaching of criterion performance). An 8-week period of extended treatment will then be implemented, followed once again by an fMRI scan. Maintenance of performance will be re-assessed at 6 months. Effects of extended treatment on maintenance will be assessed, and comparisons will be made between scans obtained at the 3 different stages. Results will provide important information regarding the role of extended treatment in long-term success of language therapy, the potential for fMRI scans to predict long-term maintenance, and will lead to important insights into the ways that the brain effects cognitive changes following treatment for alexia. These results will have important implications for the design and implementation of aphasia rehabilitation programs, which should have significant positive effects upon the lives of individuals with alexia and aphasia.