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Ann Neurol. 2016 Nov;80(5):693-707. doi: 10.1002/ana.24766. Epub 2016 Sep 19.

Direct current stimulation over the anterior temporal areas boosts semantic processing in primary progressive aphasia.

Author information

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.
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.
Department of diagnostic and functional neuroradiology, Pitié-Salpêtrière Hospital, AP-HP, Paris, France.
Department of Neurology, Saint Antoine Hospital, AP-HP, Paris, France.
Department of Neurology, Henri Mondor Hospital, AP-HP & Mondor Institute of biomedical research, INSERM U955 - Team 1, Créteil, France.
Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York, City University of New York, New York, NY.
Nuclear Medicine Department, Pitié-Salpêtrière Hospital, AP-HP & Pierre et Marie Curie University, LIB-INSERM UMR 678, Paris, France.
Cognitive Neuroscience and Information Technology Research Program, Open University of Catalonia (UOC), Barcelona, Spain.



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.


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.


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.


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.

[Indexed for MEDLINE]

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