Neurostimulation with Naming Therapy for Primary Progressive Aphasia: A Pilot Study Targeting Transcranial Direct...

Background: Transcranial Direct Current Stimulation (tDCS) in conjunction with behavioural language therapy in PPA has previously been modified for variation at the group level, but not at the individual level. This pilot study used individualised tDCS targeting by identifying regions of peak atrophy in the language system. Methods: Six PPA participants (four semantic and two non-fluent variant) were randomly allocated to receive tDCS or sham stimulation. The target electrode was selected for each based on their region of peak atrophy. Participants received naming therapy, individually calibrated according to baseline naming performance. Three sets of therapy were delivered in conjunction with tDCS (1 mA) or sham stimulation within participants' homes. The study was not powered to demonstrate efficacy but to show proof-of-concept for an individualised, home-based tDCS targeting method. Results: All participants successfully completed the protocol. In one participant the region of peak atrophy differed from that predicted by clinical syndrome. Significant gains were observed at an individual level for treated items in both groups (2/3 tDCS and 2/3 Sham). No significant changes in untreated items were observed at an individual level. Significant naming improvement in untreated items was not observed for the tDCS group and was seen at one time point only for the Sham group. Conclusions: We have demonstrated the feasibility of a novel method for selecting neurostimulation targets for PPA at the individual level. A larger study would be required to determine the long-term therapeutic efficacy of this method.