[Comparative study of the psychophysiologic relaxation effects of an optic-acoustic mind machine with relaxation music].

The present study was designed to test the effectiveness of an optical-acoustic mind machine (brain machine) in inducing relaxation. The mind machine used in this study stimulates the user with flickers of light and pulsating sounds. During the treatment the stimulation decreases from 10 to 2 hertz and increases again at half time. No other relaxation inducing effects were used. Sixteen subjects received two or three sessions of instruction with the mind machine. Afterwards the parameters listed below were continuously recorded during one session with the mind machine and one session with the presentation of relaxing environmental sounds, which was conducted one week later: Frontal EMG, SCL on the left hand, heart rate. Pre- and posttreatment samples of saliva were collected and assessed for salivary IgA (S-IgA) and salivary cortisol (S-cortisol). Changes in the subjects' self-report were measured with a bipolar adjective list. ANCOVA with repeated measures revealed a decrease for all electrophysiological parameters during the mind machine session. S-cortisol concentration decreases as S-IgA increases. The mind machine made the subjects feel warmer and calmer. The results of this with in design revealed no reliable differences between the mind machine and the relaxing sounds of nature on the physiological and self-esteem parameters. The significantly greater decrease of SCL during the mind machine session was due to the elevated baseline of this parameter. The results lead to the conclusion that the mind machine seems to be useful in inducing relaxation, but is no more effective than the relaxing nature sounds used in this study.