title: Direct current stimulation over the anterior temporal areas boosts semantic processing in primary progressive aphasia.
abstract: OBJECTIVE
  Noninvasive brain stimulation in primary progressive aphasia (PPA) is a promising approach. Yet, applied to single cases or insufficiently controlled small-cohort studies, it has not clarified its therapeutic value. We here address the effectiveness of transcranial direct current stimulation (tDCS) on the semantic PPA variant (sv-PPA), applying a rigorous study design to a large, homogeneous sv-PPA cohort.
  
  
  METHODS
  Using a double-blind, sham-controlled counterbalanced cross-over design, we applied three tDCS conditions targeting the temporal poles of 12 sv-PPA patients. Efficiency was assessed by a semantic matching task orthogonally manipulating "living"/"nonliving" categories and verbal/visual modalities. Conforming to predominantly left-lateralized damage in sv-PPA and accounts of interhemispheric inhibition, we applied left hemisphere anodal-excitatory and right hemisphere cathodal-inhibitory tDCS, compared to sham stimulation.
  
  
  RESULTS
  Prestimulation data, compared to 15 healthy controls, showed that patients had semantic disorders predominating with living categories in the verbal modality. Stimulation selectively impacted these most impaired domains: Left-excitatory and right-inhibitory tDCS improved semantic accuracy in verbal modality, and right-inhibitory tDCS improved processing speed with living categories and accuracy and processing speed in the combined verbal × living condition.
  
  
  CONCLUSIONS
  Our findings demonstrate the efficiency of tDCS in sv-PPA by generating highly specific intrasemantic effects. They provide "proof of concept" for future applications of tDCS in therapeutic multiday regimes, potentially driving sustained improvement of semantic processing. Our data also support the hotly debated existence of a left temporal-pole network for verbal semantics selectively modulated through both left-excitatory and right-inhibitory brain stimulation. Ann Neurol 2016;80:693-707.
authors.affiliation: Department of Neurology, National Reference Center for "PPA and rare dementias", Pitié Salpêtrière Hospital, AP-HP, Paris, France.|Brain & Spine Institute, ICM-UMR INSERM-CNRS-UPMC 1127, Frontlab team, Paris, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Teichmann
authors.affiliation: Department of Neurology, National Reference Center for "PPA and rare dementias", Pitié Salpêtrière Hospital, AP-HP, Paris, France.|Brain & Spine Institute, ICM-UMR INSERM-CNRS-UPMC 1127, Frontlab team, Paris, France.
authors.forename: Constance
authors.initials: C
authors.lastname: Lesoil
authors.affiliation: Brain & Spine Institute, ICM-UMR INSERM-CNRS-UPMC 1127, Frontlab team, Paris, France.|Brain & Spine Institute, UMR INSERM-CNRS-UPMC 1127, Team of Cerebral Dynamics Plasticity & Rehabilitation, Paris, France.|Laboratory for Cerebral Dynamics Plasticity & Rehabilitation, Boston University School of Medicine, Boston, MA.
authors.forename: Juliette
authors.initials: J
authors.lastname: Godard
authors.affiliation: Brain & Spine Institute, ICM-UMR INSERM-CNRS-UPMC 1127, Frontlab team, Paris, France.|Brain & Spine Institute, UMR INSERM-CNRS-UPMC 1127, Team of Cerebral Dynamics Plasticity & Rehabilitation, Paris, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Vernet
authors.affiliation: Department of diagnostic and functional neuroradiology, Pitié-Salpêtrière Hospital, AP-HP, Paris, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Bertrand
authors.affiliation: Brain & Spine Institute, ICM-UMR INSERM-CNRS-UPMC 1127, Frontlab team, Paris, France.|Department of Neurology, Saint Antoine Hospital, AP-HP, Paris, France.
authors.forename: Richard
authors.initials: R
authors.lastname: Levy
authors.affiliation: Department of Neurology, National Reference Center for "PPA and rare dementias", Pitié Salpêtrière Hospital, AP-HP, Paris, France.|Brain & Spine Institute, ICM-UMR INSERM-CNRS-UPMC 1127, Frontlab team, Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Dubois
authors.affiliation: Department of Neurology, Henri Mondor Hospital, AP-HP & Mondor Institute of biomedical research, INSERM U955 - Team 1, Créteil, France.
authors.forename: Laurie
authors.initials: L
authors.lastname: Lemoine
authors.affiliation: Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York, City University of New York, New York, NY.
authors.forename: Dennis Q
authors.initials: DQ
authors.lastname: Truong
authors.affiliation: Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York, City University of New York, New York, NY.
authors.forename: Marom
authors.initials: M
authors.lastname: Bikson
authors.affiliation: Nuclear Medicine Department, Pitié-Salpêtrière Hospital, AP-HP & Pierre et Marie Curie University, LIB-INSERM UMR 678, Paris, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Kas
authors.affiliation: Brain & Spine Institute, ICM-UMR INSERM-CNRS-UPMC 1127, Frontlab team, Paris, France.|Brain & Spine Institute, UMR INSERM-CNRS-UPMC 1127, Team of Cerebral Dynamics Plasticity & Rehabilitation, Paris, France.|Laboratory for Cerebral Dynamics Plasticity & Rehabilitation, Boston University School of Medicine, Boston, MA.|Cognitive Neuroscience and Information Technology Research Program, Open University of Catalonia (UOC), Barcelona, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Valero-Cabré
mesh_terms: D000368:Aged; D018888:Aphasia, Primary Progressive / Q000628:therapy*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D012660:Semantics; D013702:Temporal Lobe; D065908:Transcranial Direct Current Stimulation / Q000379:methods*