OBJECTIVE: Transcranial direct current stimulation (tDCS), a non-invasive, painless method of applying direct current electrical stimulation to specific areas of the brain, is an effective method for enhancing attention and post-stroke fatigue, as shown by behavioral improvements in post-stroke populations. While behavioral evidence supports this method, there is a paucity of physiological data corroboration of this improvement. The current study is designed to investigate if a single session of tDCS will improve attention and fatigue as shown by relevant physiological methods in persons with post-stroke aphasia. METHODS: Ten participants (5 male
mean age: 62.8) engaged in two identically structured data collection sessions with at least a 3-day wash-out period between them. Sessions started with a sustained attention task with simultaneous electroencephalography (EEG) and pupillometry data collection, followed by an attention training program with simultaneous active or sham tDCS. Following tDCS, participants repeated the sustained attention task with simultaneous EEG and pupillometry data collection. Participants received active tDCS during one session, and sham tDCS during the other, with the order randomized. RESULTS: No differences between conditions were found for either behavioral results from the sustained attention task (i.e., reaction time of correct responses
CONCLUSION: Changes in pupil diameter observed in the active stimulation condition suggest activation of the locus coeruleus-norepinephrine (LC-NE) pathway within a single session of tDCS administration, but the lack of significant changes for either response time or attention states indicate no direct effect on behaviorally measured or EEG measured attention within the same timeframe. Responses to active stimulation in terms of subjective fatigue rating varied between individual participants
overall, active tDCS mitigated task-based fatigue. More research is needed to investigate this relationship.