Evaluation of the effect of caffeine consumption on cognitive functions by electroencephalography

Abstract

Objective: To evaluate cognitive performance and neurophysiological changes after caffeine consumption in individuals who regularly consume different amounts of caffeine. Materials and Methods: Thirty-seven people aged 18-25 were divided into two groups according to their caffeine consumption as less than 3 mg/kg/day (low consumption group; LC) and more than 3 mg/kg/ day (high-consumption group; HC). Electroencephalography (EEG) and Montreal Cognitive Assessment test (MoCA) were performed in both groups (baseline records). One week later, caffeinated (Caff) and decaffeinated (Decaff) coffee were randomly given to LC and HC. Thus, four groups were formed (LC+Caff, LC+Decaff, HC+Caff and HC+Decaff). EEG was repeated one hour after coffee, and MoCA was performed within 20 minutes. Results: In baseline eyes-opened EEG, the power of beta2 and delta were higher in the LC group than in the HC. After coffee consumption in the eyes-opened EEG, alpha1 and alpha2 power were significantly reduced in the HC+Caff. Following coffee consumption, the MoCA score increased significantly in the HC+Decaff and LC+Caff groups compared with the baseline. Conclusion: Our study showed that low caffeine consumers had increased brain activity and cognitive performance post consumption high amounts of caffeine. However, this effect was less in high caffeine consumers. Therefore, caffeine habituation may alter the brain's response to caffeine.