Data collection and procedures
Both groups underwent baseline assessment before the first session and post-intervention assessment after the final session. The EEG and questionnaire surveys were conducted in a testing room in the study facility without disturbances. Moreover, laboratory tests for the NK cell count, cortisol levels, and protein levels were conducted by a clinical pathologist at the study facility. The EEG was performed within 10 min, including preparation, while the survey, including the MMPI-2, took about 90–120 min. Participants were assigned an identification number, which was used to manage and document their baseline and post-intervention data.