Background: Highly educated students and professionals in cognitively demanding careers are often at risk of acute sleep deprivation. In the past few decades, the trend toward increasing psychostimulant abuse has elicited the need for safer alternatives to cognitive enhancement. Transcranial direct cranial stimulation (tDCS) and high dose cocoa flavonoids (HDCF) have been recently studied as promising alternatives. However, these studies had methodological differences, sometimes conflicting results, and none to date have assessed their combined effects.

Objective: To determine if anodal tDCS and HDCF will improve working memory (WM) scores in acutely sleep-deprived highly educated healthy participants.

Methods: We propose a single-center, randomized, placebo-controlled (double-dummy), double-blind, early phase II study, in which 164 acutely sleep-deprived 21-40 year-old students or professionals in cognitively demanding fields will be randomized in a 2x2 factorial fashion to one of the following groups: anodal tDCS + HDCF, anodal tDCS + placebo CF, sham tDCS + HDCF, and sham tDCS + placebo CF. The primary outcome is a composite score of n-back and dual n-back tests following the intervention. Secondary outcomes include exploratory subgroup analyses for gender and cognitive score adjusted for time and task, psychomotor vigilance task, mental fatigue visual analogue scale, quantitative electroencephalogram, and tDCS adverse events questionnaire. 

Potential impact of the study: This study will allow us to assess the effects of each intervention alone on WM as well as (for the first time) identify any potential synergistic effects resulting from the combined interventions. This, in turn, may generate hypotheses for future studies on cognitive impairment due to both acute/chronic sleep deprivation and pathologic disorders.