B – 83 Electroencephalogram Biomarkers of Verbal Fluency: The Role of Transcranial Direct Current Stimulation in Modulating Cognitive Performance in Depressed College Students

Abstract Objective The aim of this study is to determine if anodal transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex improves verbal fluency in depressed college students. Method Twenty-one college students with a score of 17 or more on the Center for Epidemiological Studies Depression Scale (CESD) were randomly assigned to either a tDCS intervention condition or sham tDCS condition. In the tDCS intervention condition, two 14-minute sessions at an intensity of 2mA were conducted, with the anode placed at F3 and cathodes placed at Fp1, Fz, C3, and F7. The sham condition consisted of the same duration and electrode montage, but 0mA were delivered. A baseline assessment consisting of the Vocabulary and Matrix Reasoning subtests from the Wechsler Abbreviated Scales of Intelligence, Second Edition (WASI-II) and the Verbal Fluency Test Form A from the Delis-Kaplan Executive Function System (D-KEFS) was conducted. Following tDCS intervention, the Verbal Fluency Test Form B was administered. Electroencephalogram (EEG) recordings were obtained pre- and post-stimulation to observe physiological changes. Results A repeated measures analysis of variance (ANOVA) was performed and revealed no significant differences in alpha beta ratios before and after true or sham tDCS (F=1.14, p=0.30). Furthermore, tDCS did not affect verbal fluency (F=1.36, p=0.26). Conclusion Results suggest that tDCS does not cause any significant physiological changes in the brain, as measured by EEG several minutes after application. Furthermore, results suggest that a single trial of tDCS over the dorsolateral prefrontal cortex does not improve verbal fluency in depressed college students.