“…To analyze such characteristics of sleep EEGs accurately, research has been conducted to quantitatively analyze the frequency of EEGs during each sleep stage. (15)(16)(17)(18) With the development of the Mind Switch by Kirkup et al in 1997, research for determing brain functions and the processes of mental mechanisms that occur in the brain using EEGs has gained considerable attention. (19) In such research, the interpretation of mental mechanisms that occur in the human cognitive process has been attempted using EEGs.…”