The study protocol was approved by the human research ethical committee of our institution (HSC-HREC-61-006-02-1). All the participants signed informed consent letters, and the experiment was explained to them. We acquired EEGs from two age groups, a middle-aged group (age range, 41 to 60 years; mean age= 50.50 ± 5.77 years) and an elderly group (age range, 61 to 84 years; mean age= 71.03 ± 5.45 years). Each group consisted of 20 healthy participants who had no previous history of any psychological or neurological disorder.
