BACKGROUND: The application of transcranial direct current stimulation
(tDCS) in chronic post stroke aphasia is documented in a substantial literature, and there
is some new evidence that tDCS can augment favorable language outcomes in primary
progressive aphasia. Anodal tDCS is most often applied to the left hemisphere language
areas to increase cortical excitability (increase the threshold of activation) and
cathodal tDCS is most often applied to the right hemisphere homotopic areas to inhibit
over activation in contralesional right homologues of language areas. Outcomes usually are
based on neuropsychological and language test performance, following a medical model which
emphasizes impairment of function, rather than a model which emphasizes functional
communication.
OBJECTIVE: In this paper, we review current literature of tDCS as it is
being used as a research tool, and discuss future implementation of tDCS as an adjuvant
treatment to behavioral speech-language pathology intervention.
METHODS: We review literature describing non-invasive brain stimulation, the
mechanism of tDCS, and studies of tDCS in aphasia and neurodegenerative disorders. We
discuss future clinical applications.
RESULTS/CONCLUSIONS: tDCS is a promising adjunct to traditional
speech-language pathology intervention to address speech-language deficits after stroke
and in the neurodegenerative disease, primary progressive aphasia. Limited data are
available regarding how performance on these types of specific tasks translates to
functional communication outcomes.
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