Assessment of HD-tDCS Effects on Vigilance Performance

Vigilance is critical across operationally diverse work settings. Because performance on these tasks often declines over time, vigilance research has focused on identifying methods for maintaining optimal performance. Past studies have suggested that anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) can improve vigilance performance. However, conventional tDCS comparisons reported greater benefits from left-hemispheric than right-hemispheric stimulation, despite evidence that vigilance primarily relies on right-hemispheric attentional networks. Because conventional tDCS produces diffuse current flow, the present study utilized high-definition tDCS (HD-tDCS) to more precisely compare left- and right-hemispheric stimulation during vigilance performance. Forty-two participants were randomly assigned to left DLPFC, right DLPFC, or sham HD-tDCS conditions while completing a 40-min cognitive vigilance task. Surprisingly, HD-tDCS did not influence vigilance performance, regardless of the hemisphere. These findings highlight the need for further research evaluating the reliability, effectiveness, and best practices of tDCS for enhancing vigilance performance.