title: Augmentation of spelling therapy with transcranial direct current stimulation in primary progressive aphasia: Preliminary results and challenges.
abstract: BACKGROUND
  Primary progressive aphasia (PPA) is a neurodegenerative disease that primarily affects language functions and often begins in the fifth or sixth decade of life. The devastating effects on work and family life call for the investigation of treatment alternatives. In this article, we present new data indicating that neuromodulatory treatment, using transcranial direct current stimulation (tDCS) combined with a spelling intervention, shows some promise for maintaining or even improving language, at least temporarily, in PPA.
  
  
  OBJECTIVE
  The main aim of the present article is to determine whether tDCS plus spelling intervention is more effective than spelling intervention alone in treating written language in PPA. We also asked whether the effects of tDCS are sustained longer than the effects of spelling intervention alone.
  
  
  METHODS
  We present data from six PPA participants who underwent anodal tDCS or sham plus spelling intervention in a within-subject crossover design. Each stimulation condition lasted 3 weeks or a total of 15 sessions with a 2-month interval in between. Participants were evaluated on treatment tasks as well as on other language and cognitive tasks at 2-week and 2-month follow-up intervals after each stimulation condition.
  
  
  RESULTS
  All participants showed improvement in spelling (with sham or tDCS). There was no difference in the treated items between the two conditions. There was, however, consistent and significant improvement for untrained items only in the tDCS plus spelling intervention condition. Furthermore, the improvement lasted longer in the tDCS plus spelling intervention condition compared to sham plus spelling intervention condition.
  
  
  CONCLUSIONS
  Neuromodulation with tDCS offers promise as a means of augmenting language therapy to improve written language function at least temporarily in PPA. The consistent finding of generalisation of treatment benefits to untreated items and the superior sustainability of treatment effects with tDCS justifies further investigations. However, the small sample size still requires caution in interpretation. Present interventions need to be optimised, and particular challenges, such as ways to account for the variable effect of degeneration in each individual, are discussed.
authors.affiliation: Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA.
authors.forename: Kyrana
authors.initials: K
authors.lastname: Tsapkini
authors.affiliation: Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Constantine
authors.initials: C
authors.lastname: Frangakis
authors.affiliation: Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA.
authors.forename: Yessenia
authors.initials: Y
authors.lastname: Gomez
authors.affiliation: Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA.
authors.forename: Cameron
authors.initials: C
authors.lastname: Davis
authors.affiliation: Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA ; Department of Physical Medicine & Rehabilitation, Johns Hopkins Medicine, Baltimore, MD, USA ; Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Argye E
authors.initials: AE
authors.lastname: Hillis
keywords: Intervention; Language rehabilitation; PPA; Spelling; Writing; tDCS