Augmenting Cognitive Training In Older Adults

A two-phase adaptive randomized clinical trial will examine the individual and combined impact of pairing cognitive training with transcranial direct current stimulation (tDCS). tDCS is a method of non-invasive brain stimulation that directly stimulates brain regions involved in active cognitive function and could enhance neural plasticity when paired with a training task. We will compare changes in cognitive and brain function resulting from CT and ET combined with tDCS using a comprehensive neurocognitive, clinical, and multimodal neuroimaging assessment of brain structure, function, and metabolic state. Functional magnetic resonance imaging (FMRI) will be used to assess brain response during working memory, attention, and memory encoding; the active cognitive abilities trained by CT. Proton magnetic resonance spectroscopy (MRS) will assess cerebral metabolites, including GABA concentrations sensitive to neural plasticity. We hypothesize that: 1) tDCS will enhance neurocognitive function, brain function, and functional outcomes from CT, with combined CT and tDCS providing the most benefit; 2) Effects of tDCS on CT will be maintained up to 12 months following training, and 3) Neuroimaging biomarkers of cerebral metabolism, neural plasticity (GABA concentrations) and functional brain response (FMRI) during resting vs. active cognitive tasks will predict individual response to tDCS.