title: A comparison of the effects of transcranial direct current stimulation and caffeine on vigilance and cognitive performance during extended wakefulness.
abstract: BACKGROUND
  Sleep deprivation from extended duty hours is a common complaint for many occupations. Caffeine is one of the most common countermeasures used to combat fatigue. However, the benefits of caffeine decline over time and with chronic use.
  
  
  OBJECTIVE
  Our objective was to evaluate the efficacy of anodal transcranial direct current stimulation (tDCS) applied to the pre-frontal cortex at 2 mA for 30 min to remediate the effects of sleep deprivation and to compare the behavioral effects of tDCS with those of caffeine.
  
  
  METHODS
  Three groups of 10 participants each received either active tDCS with placebo gum, caffeine gum with sham tDCS, or sham tDCS with placebo gum during 30 h of extended wakefulness.
  
  
  RESULTS
  Our results show that tDCS prevented a decrement in vigilance and led to better subjective ratings for fatigue, drowsiness, energy, and composite mood compared to caffeine and control in sleep-deprived individuals. Both the tDCS and caffeine produced similar improvements in latencies on a short-term memory task and faster reaction times in a psychomotor task when compared to the placebo group. Interestingly, changes in accuracy for the tDCS group were not correlated to changes in mood; whereas, there was a relationship for the caffeine and sham groups.
  
  
  CONCLUSIONS
  Our data suggest that tDCS could be a useful fatigue countermeasure and may be more beneficial than caffeine since boosts in performance and mood last several hours.
authors.affiliation: Infoscitex Inc., Dayton, OH, USA.
authors.forename: Lindsey K
authors.initials: LK
authors.lastname: McIntire
authors.affiliation: 711th HPW, Applied Neuroscience Branch, 2510 Fifth Street, Bldg 840, USA. Electronic address: Andy.McKinley@wpafb.af.mil.
authors.forename: R Andy
authors.initials: RA
authors.lastname: McKinley
authors.affiliation: Infoscitex Inc., Dayton, OH, USA.
authors.forename: Chuck
authors.initials: C
authors.lastname: Goodyear
authors.affiliation: Infoscitex Inc., Dayton, OH, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Nelson
mesh_terms: D000328:Adult; D000339:Affect / Q000187:drug effects / Q000502:physiology; D001288:Attention / Q000187:drug effects* / Q000502:physiology; D002110:Caffeine / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects* / Q000502:physiology*; D005221:Fatigue / Q000503:physiopathology / Q000523:psychology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects / Q000502:physiology; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012892:Sleep Deprivation / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D012894:Sleep Stages / Q000187:drug effects; D011795:Surveys and Questionnaires; D013997:Time Factors; D065908:Transcranial Direct Current Stimulation; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology*
chemical_list: D002110:Caffeine
keywords: Attention; Caffeine; Cognition; Sleep deprivation; Transcranial direct current stimulation