Modulation of large-scale network connectivity and glutamatergic concentrations by transcranialdirect current stimulation (tDCS): A preliminary multimodal imaging study

s / Brain Stimulation 7 (2014) e1ee16 e7 assigned to anodal or sham tDCS(2.0mA x 20 minutes; anode over left primary motor strip 5cm lateral to vertex of skull along interaural line, cathode over right supraorbital ridge). Preliminary results from four participants (three sham, one anodal) reveal that participants receiving sham improved in their Aphasia Quotient (from Western Aphasia Battery, Kertesz, 2006), with two improving above (5.8) or near (4.4) the clinically significant benchmark of 5 points (Katz & Wertz, 1997). Participants receiving sham stimulation also improved in measures of speech motor control (diadochokinetic tests) and a verbal fluency task. The participant receiving anodal tDCS showed minimal changes between the preand post-treatment measures. A control task (symbol cancellation) revealed no changes. These findings compel further research to determine the role of tDCS andmotor therapy in speech/language outcomes with and without targeted aphasia/ apraxia therapy.