Augmenting Language Therapy for Aphasia: Levodopa

Stroke is the third leading cause of death and the most common cause of disability in the United States. According to the American Stroke Association, the prevalence of stroke in the U.S. is approximately 4.8 million with approximately 700,000 additional strokes occurring annually. Approximately 150,000 to 250,000 stroke survivors becoming severely and permanently disabled each year. A common neurological deficit among stroke survivors, and thus a substantial contributor to post-stroke disability, is aphasia. The loss of, or difficulty with language is extremely debilitating and has enormous social and economic impact on quality of life. Presently, the only treatment available for persons with aphasia is speech-language rehabilitation. With rehabilitation only, however, many patients achieve a less than satisfactory improvement in speech-language function, and thus are left with significant disability. To enhance motor and language recovery in patients with neurological impairments, interest in the use of novel biological therapies, including pharmacological agents, has recently emerged. There is preliminary evidence that increased levels of dopamine, in combination with language treatment, may improve the deficits of aphasia following stroke. Most studies have investigated the adjunctive effects of the dopamine agonist bromocriptine, with mixed results. However, new evidence is suggesting that levodopa, a precursor to dopamine, may be more effective in promoting language learning. This study proposes to evaluate the effectiveness of levodopa in study subjects with Broca's aphasia after stroke, delivered concurrent with speech-language rehabilitation. The language changes in subjects who receive speech and language therapy combined with levodopa will be compared to that of subjects who receive the same speech-language rehabilitation but with a placebo (i.e. a pill that does not contain the study drug, levodopa). The two study groups will be compared to determine the degree to which improvements in language performance occur and the degree to which they are maintained over time. The protocol is double-blind: neither subjects nor researchers will know whether a subject took levodopa or placebo until the study's conclusion.