tDCS over the left inferior frontal cortex improves speech production in aphasia

Inthisstudy,weinvestigatedthecombinedeffectoftranscranialdirectcurrentstimulation(tDCS)andanintensiveConversationaltherapytreatmentondiscourseskillsin12personswithchronicaphasia.Sixshortvideoclipsdepictingeverydaylifecontextswereprepared.Threevideoclipswereusedtoelicitspontaneousconversationduringtreatment.Theremainingthreewerepresentedonlybeforeandafterthetherapy.ParticipantswerepromptedtotalkaboutthecontentsofeachvideoclipwhilestimulatedwithtDCS(20min1mA)overthelefthemisphereinthreeconditions:anodictDCSovertheBroca’sarea,anodictDCSovertheWernicke’sarea,andashamcondition.Eachexperimentalconditionwasperformedfor10consecutivedailysessionswith14daysofintersessioninterval.AfterstimulationoverBroca’sarea,theparticipantsproducedmoreContentUnits,verbsandsentencesthanintheremainingtwoconditions.Importantly,thisimprovementwasstilldetectable1monthaftertheendoftreatmentanditseffectsweregeneralizedalsotothethreevideoclipsthathadbeenadministeredatthebeginningandattheendofthetherapysessions.Inconclusion,anodictDCSappliedovertheleftBroca’sareatogetherwithanintensive“ConversationalTherapy”treatmentimprovesinformativespeechinpersonswithchronicaphasia.WebelievethatpositivetDCSeffectsmaybefurtherextendedtootherlanguagedomains,suchastherecoveryofspeechproduction.