McIntire LK, et al. – The efficacy of transcranial direct current stimulation (tDCS) was compared with caffeine as a fatigue countermeasure. Findings indicated that tDCS could be a powerful fatigue countermeasure. Its effects appeared to be comparable or possibly more beneficial than caffeine as they were longer lasting and mood remains more positive.

Methods

• In this study, 5 groups of ten participants each received either active tDCS and placebo gum at 1800, caffeine gum with sham tDCS at 1800, active tDCS and placebo gum at 0400, caffeine gum with sham tDCS at 0400, or sham tDCS with placebo gum at 1800 and 0400 during 36–h of sustained wakefulness.
• Participants completed a vigilance task, working memory task, psychomotor vigilance task (PVT), and a procedural game beginning at 1800 h and continued every two hours throughout the night until 1900 the next day.

Results

• Fidnings showed that tDCS dosed at 1800 provided 6 h of improved attentional accuracy and reaction times compared to the control group.
• However, caffeine did not produce an effect.
• Both tDCS groups also had an improved effect on mood.
• Participants receiving tDCS reported feeling more vigor, less fatigue, and less bored throughout the night compared to the control and caffeine groups.