The development of qigong EEG feedback control system

The development of a new- type two loop QIGONG EEG feedback control system based on a IBM PC/XT computer is presented, and the specific measure of artifact rejection for the clinical practice of this system is discussed. The system ,with varied EEG's index outputs on the CRT and the printer, organically combines the EEG biofeedback and the physical stimulation feedback control , fully utilizes the latest achievement in the research on EEG's activities Qigong state and possesses the value of clinical practice .by the utilization of this system, the EEG 's activity may be effectively regulated, and effect of Qigong practice is received . Finally ,clinical experimental results of EEG feedback control given.

1. INTRODUCTION .
EEG biofeedback and begin evoked potential techniques are two-principal aspects in the domain of EEG feedback control. EEG alpha feedback is widely researched in recent years. It is actually one-loop EEG control. Brain evoked potential technique is applied in diagnosis of abnormal EEG activity . Brain evoking is a kind of open loop EEG control.
Qigong (Chinese traditional Qigong or transcendental meditation) is manifested a effective method of recovery.
- studies show EEG changes during Qi-gong as following:
(1). The amplitude of alpha is increased at the end of Qigong practice.
(2). There is a contrast tendency to shift from alpha tO slow frequencies.
(3). Increases. in EEG coherence during practice of Qigong indicate increased ordering of brain wave activity.
The Qigong EEG feedback control system developed by us organically. feedback .control fully utilizes the latest achievement in the research on BEG' activities in Qi-gong state, and possesses the value of clinical practice .It is a newtype two-loop EEG feedback control system.

2. SYSTEM CONSTRUCTION
The Qigong EEG feedback control systes consists of RBG amplifier, EEG pre-processor, A-D and D-A converter, IBM PC /XT microcomputer, printer, CRT, power amplifier, small coil, loudspeaker. .
Printer and CRT are used to output EEG feedback control results. EEG pre-processor is a notch filter inserted at 50 Hz .
The sine wave modulated magnetic and auditory signals are produced respectively by a small coil and a loudspeaker . There
are two kinds of auditory signals, control signals and warning signals . During -Qigong EEG feedback control training , the main objective of subject i8 to decrease the appearing times of warning sound.

3. SYSTEM SOFTWARE
The system software consists of 4 elements that ate initiation, EEG signal acquisition: and analysis, strategy decision and EEG FEEDBACK CONTROL,result output.
Firstly, a digital control model is set up, and the Kaiser window is calculated. Then, the EEG signals are digitized on-line to 12 bits at 64 sampled per second per channel in a A-D converter (PC-1216) connected to a IBM PC/XT microcomputer. simultaneously with the data acquisition ,eight channels of the. EEG (256 samples per channel) are processed by adding Kaiser window, and Fourier transformed . By use of EEG power spectrum, EEG alpha rhythm relative power (alpha index) EEG main frequency ,and total coherence in alpha band are calculated. | According to those EEG indexes ,the strategy of B G feedback l control is decided, and EEG real-time feedback control is carried out.
Finally, the system outputs the EEG index dynamic curve sad the BEG coherence spectral array (COSPAR)- on the printer and CRT.

4:. CLINICAL EXPERIMENT
A total of four volunteer subjects of both sex students were studied on the Qigong EEG feedback control: training . Subjects were seated in a comfortable chair within a sound-controlled room. With eye -slight closing , subjects concentrated on the control sound and warning sound, and tried to decrease the appearance of warning sound by subjective effort. .
Records with linked ears for reference electrode, were.taken fro- electrodes F3, F4 of the 10-20 system l The ground was to Fz
The time constant was 0.1 .second, the high pass limitation 30 c/sec, the EEG machine a model ND-82B polygraph. EEG analysis results were stored in a file on magnetic disk. The small magnetic coil was applied to Cz.
In the earlier days of training , subjects were not able to effectively regulate themselves EEG 's activity due to lack of experience. After several sessions of training , they gradually mastered the ability to control EEG 's activity. The EEG index changes of one subject during Qigong BEG feedback control; training was shown output by a printer. . .
The alpha relative power ( alpha index) and the coherence (F3/F4) increased . The main frequency, thetas and beta relative powers decreased . A EEG state of Qigong appeared. .
The clinical experimental results ..of Qigong EEG feedback control training suggested that EEG's activity was able to be effectively regulated in 20 minutes ,and effect of Qigong practice was received by the utilization of the Qigong EEG feedback control system.