Two protocols were applied for training NF: (1) enhancing high-frequency alpha protocol in frontocentral areas of brain and suppressing theta waves and (2) enhancing beta in frontocentral areas of brain and suppressing theta waves. The system was a Procomp Infinity from Thought Technology Ltd. (Montreal, QC, Canada) running Biograph Infinity software. The session included 5-minute baseline record and 20-minute intervention in frontal area (4 games, five minutes each) and 20 bipolar intervention therapies in central areas. In alpha protocol, participants needed to suppress theta waves (4–7 Hz) and to enhance the high-frequency alpha waves (10–12 Hz). In beta protocol, participants needed to suppress theta waves and to enhance low-frequency beta waves (12–15 Hz, SMR).