To investigate the efficacy of right cerebellar tDCS as a therapeutic adjuvant in left-hemisphere stroke survivors with chronic aphasia.

Aphasia is a common result of left-hemisphere stroke that can cause severe communication impairments. Current treatment involves behavioral therapy, but these interventions are often only moderately effective and show variable results. Recently, neurostimulation has gained traction as a potential additional avenue for neurorehabilitation. Neurostimulation applied to the scalp modulates the excitability of residual tissue and facilitates neuroplasticity. However, the cortical lesions common in post-stroke aphasia affect the electrical field in unpredictable ways, potentially preventing stimulation from reaching perilesional tissue associated with optimal recovery. Our ongoing tDCS study addresses this problem by stimulating over right cerebellum, which is known to be functionally and structurally connected to contralateral, ipsilesional tissue that is the target of neurostimulation.

Outcome measures include naming performance on the Philadelphia Naming Test, letter and category fluency, verb naming and generation, and a cloze probability task. Brain imaging will be investigated for treatment effects as measured by pre-post changes in task activation and gray matter density. Results will be compared to the sham group from a previous neurostimulation trial receiving comparable treatment.

Improvement on behavioral or imaging outcome measures may indicate that the right posterolateral cerebellum holds value as a target stimulation site in post-stroke aphasia and warrants further investigation.