tDCS Works Better Than Caffeine

So, using tDCS, McKinley’s lab kept 30 people up for 30 hours to see how they fared with and without fatigue interventions. Essentially, they compared the effects of 200 mg of caffeine (about equal to 2 cups of coffee) to 30 minutes of tDCS at two milliamps (mA) applied to an area of the brain called the dorsolateral pre-frontal cortex, which is very important for the cognitive processes of attention and vigilance. The results suggest that applying electricity to a brain for half an hour is more effective than consuming something caffeinated.

Specifically, the people who were electrically stimulated were more vigilant for longer than those given caffeine -- up to six hours versus two. Previous studies found that a shorter duration of tDCS could modulate vigilance for 30 to 90 minutes, which is within the range of the two hours of caffeine action. This time, said McKinley with excitement, “we recorded 6 hours after we gave the stimulation. This time it was 30 minutes of stimulation, and we did not see the performance taper off… there’s got to be a point where it drops off again, we just haven’t reached that… We were very surprised that 6 hours later it was still working… exciting, but also a little baffling.”

Additionally, based on subjective questionnaires, they were able to deduce that people actually felt better on tDCS than caffeine. McKinley expressed that, “their overall mood rating was just better. They felt less fatigued, less drowsy, and more energetic… The reason that we included the subjective questionnaires is that we've been getting a lot of anecdotal evidence with people leaving saying ‘I feel more focused’ or ‘I feel more energized’, so we wanted to get some data that we could analyze that would help answer the question. Do people feel differently when they get the stimulation? And, at least when they are sleep-deprived, the answer is yes.”