The goal of this project is to investigate how linguistically grounded intensive language treatment for individuals with aphasia after stroke can be enhanced by cortical stimulation, performed with implanted electrodes. We hypothesize that cortical stimulation, administered during intensive behavioral language treatment, will strengthen and sustain learning effects. Many speakers with Broca's aphasia present with agrammatism, i.e. difficulty with comprehending and producing sentences, particularly sentences with complex syntax. Research into behavioral treatment for aphasia is progressively leading to more refined methods of intervention. However, although language improvement in speakers with aphasia can still be shown many years after their stroke, there does seem to be a natural, neurophysiological boundary as to what is possible to achieve with behavioral therapy alone. In the current research project, therefore, we will assess the potential to enhance and sustain the beneficial effects of language treatment, by stimulating core brain areas that are known to potentially support language processing of the kind that is trained, simultaneous to behavioral intervention. We expect a program of intensive and focal language treatment, in combination with cortical stimulation of crucial language areas, to lead to significant and long-lasting improvement of language functions in agrammatic aphasia, in excess of the improvement seen after treatment without cortical stimulation. This novel research brings together a multidisciplinary team of established researchers in the areas of neurosurgery and cortical stimulation, neurophysiology, neurolinguistics and treatment for aphasia and holds promise to enhance language recovery in aphasia, raising the existing cap on language improvement in aphasia. Ten participants with agrammatic aphasia will receive 64 sessions of intense language treatment, focused on sentence building processes and grammatical markers. Prior to the treatment phase, five of these participants will be implanted with a cortical stimulation device, which will be switched on during language behavioral treatment. Functional imaging studies are used to determine optimal implant localization, as well as to investigate effects of treatment and stimulation on neural plasticity. An extensive battery of language tests will be used to assess treatment effects and their maintenance in the two subject groups.
If the project is successful, it will lay the groundwork for a truly new approach to aphasia treatment. This approach targets the physical cause of the language impairment, namely, damage to neuronal networks involved in language processing and production, through direct cortical stimulation in combination with language therapy.