Secondary outcomes are the sleep log , the Beck Depression Inventory ( BDI ) , the State-Trait Anxiety Inventory ( STAI ) , the World Health Organization Quality of Life Abbreviated Version ( WHOQOL-BREF ) , the Korean-Auditory Verbal Learning Test ( K-AVLT ) , the Digit Span Test ( DS ) , Event Related Potentials ( ERPs ) and heart rate variability ( HRV ) to assess emotional states , sleep quality , cognitive functioning , and electro-physiological changes.Subjects are assessed at three time points : baseline , post-treatment and follow-up .