Project 2 Aphasia, or impairment of language, is one of the most devastating problems after left hemisphere stroke, because it can interfere with an individual's social interactions, ability to return to work, and even simple daily activities, such as returning email or answering the phone. Speech and language treatment (SALT) can be helpful in restoring language function, but recovery is often incomplete. Recent studies indicate that the effectiveness of SALT can be augmented by concurrent Transcranial Direct Current Stimulation (tDCS), a noninvasive, non-painful, electrical stimulation of the brain. It is believed that tDCS boosts neural plasticity that underlies recovery with SALT. The optimum time to apply tDCS with SALT is unknown. Animal studies indicate that neuroplasticity is greatest in the first few weeks to months after stroke, but that the duration of neuroplasticity (the window of time during which undamaged areas might be able to assume functions of the damaged areas) might be extended by administration of selective serotonin reuptake inhbitors (SSRIs). With this proposal, we aim to identify to optimal time to apply anodal tDCS (A-tDCS) along with SALT. We will compare the effects of A-tDCS plus SALT to sham plus SALT delivered by computer over 15 sessions in ?subacute? (beginning at <3 months), and compare these effects to those reported with the same interventions in chronic stroke. We will evaluate the effects of interventions on naming untrained objects (one of the most common deficits in aphasia) as well as the effects on content, efficiency, and word-retrieval of narrative speech, quality of life, and disability. We will evaluate the influence of treatment and demographic variables, such as electrode placement, time from stroke to initiation of treatment, lesion volume, aphasia and stroke severity, and education on outcome. We will also evaluate the influence of SSRI use since stroke onset on the effectiveness of SALT with and without A-tDCS in subacute stroke. We will also test the hypothesis that SSRI use eliminates the influence of delaying onset of treatment (within the first three months) by extending the duration of neuroplasticity after stroke. Finally, we will evaluate the effects of A-tDCS on ?functional connectivity? at rest (or correlations in activation between regions of ?the language network? in the brain versus other networks in the brain, such as the motor network, using resting state functional connectivity MRI before any intervention and after A-tDCS or sham with SALT.
This aim may shed light on the mechanisms of how A- tDCS affects language, and/or how language recovers with or without A-tDCS. We will test our hypotheses in a double-blind, randomized, sham-controlled trial. Neither the participant with aphasia nor the investigator will be unmasked until the end of the study. The long-term aim of this study is to provide the basis for a Phase III randomized controlled trial of A-tDCS vs sham with concurrent SALT for treatment of subacute aphasia. This study will help us determine whether or not to include only individuals taking SSRIs, or if it is important to control for SSRI use in the larger study.
Project 2 This research will contribute to determining if and when transcranial Direct Current Stimuluation (tDCS) boosts language therapy in helping people recover from language impairment (aphasia) after stroke. Aphasia has an important impact on the interpersonal relationships of stroke survivors and their re-entry into work and social settings. This research will lay the groundwork for designing a Phase III clinical trial of tDCS + language therapy for aphasia early after stroke.
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