title: Can tDCS enhance item-specific effects and generalization after linguistically motivated aphasia therapy for verbs?
abstract: BACKGROUND
  Aphasia therapy focusing on abstract properties of language promotes both item-specific effects and generalization to untreated materials. Neuromodulation with transcranial Direct Current Stimulation (tDCS) has been shown to enhance item-specific improvement, but its potential to enhance generalization has not been systematically investigated. Here, we test the efficacy of ACTION (a linguistically motivated protocol) and tDCS in producing item-specific and generalized improvement in aphasia.
  
  
  METHODS
  Nine individuals with post-stroke aphasia participated in this study. Participants were pre-tested with a diagnostic language battery and a cognitive screening. Experimental tasks were administered over multiple baselines. Production of infinitives, of finite verbs and of full sentences were assessed before and after each treatment phase. Nonword repetition was used as a control measure. Each subject was treated in two phases. Ten daily 1-h treatment sessions were provided per phase, in a double-blind, cross-over design. Linguistically-motivated language therapy focusing on verb inflection and sentence construction was provided in both phases. Each session began with 20 min of real or sham tDCS. Stimulation site was determined individually, based on MRI scans.
  
  
  RESULTS
  Group data showed improved production of treated and untreated verbs, attesting the efficacy of behavioral treatment, and its potential to yield generalization. Each individual showed significant item-specific improvement. Generalization occurred in the first phase of treatment for all subjects, and in the second phase for two subjects. Stimulation effects at the group level were significant for treated and untreated verbs altogether, but a ceiling effect for Sham cannot be excluded, as scores between real tDCS and Sham differed only before treatment.
  
  
  CONCLUSIONS
  Our data demonstrate the efficacy of ACTION and suggest that tDCS may enhance both item-specific effects and generalization.
authors.affiliation: International Doctorate in Experimental Approaches to Language And Brain (IDEALAB, Universities of Trento, Groningen, Potsdam, Newcastle and Macquarie University)Rovereto, Italy; Center for Mind/Brain Sciences and Center for Neurocognitive Rehabilitation, University of TrentoRovereto, Italy; Center for Language and Cognition Groningen, University of GroningenGroningen, Netherlands.
authors.forename: Vânia
authors.initials: V
authors.lastname: de Aguiar
authors.affiliation: Center for Language and Cognition Groningen, University of Groningen Groningen, Netherlands.
authors.forename: Roelien
authors.initials: R
authors.lastname: Bastiaanse
authors.affiliation: S.C.A. Associates Rome, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Capasso
authors.affiliation: Neuromotor and Cognitive Rehabilitation Research Centre, USO Neurological Rehabilitation, Azienda Ospedaliera Universitaria Integrata (AOUI) of VeronaVerona, Italy; Department of Neurological and Movement Sciences, University of VeronaVerona, Italy.
authors.forename: Marialuisa
authors.initials: M
authors.lastname: Gandolfi
authors.affiliation: Neuromotor and Cognitive Rehabilitation Research Centre, USO Neurological Rehabilitation, Azienda Ospedaliera Universitaria Integrata (AOUI) of VeronaVerona, Italy; Department of Neurological and Movement Sciences, University of VeronaVerona, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Smania
authors.affiliation: Neurology, Santa Maria del Carmine Hospital Rovereto, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Rossi
authors.affiliation: Center for Mind/Brain Sciences and Center for Neurocognitive Rehabilitation, University of Trento Rovereto, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Miceli
keywords: aphasia rehabilitation; argument structure; generalization; linguistically motivated therapy; neuromodulation; sentence production; transcranial direct current stimulation (tDCS); verb retrieval