[Some scientific feedback from biofeedback].

This paper emphasizes the heuristic value of biofeedback in psychiatry. The efficacy of biofeedback in the treatment of headaches appears well established. Using this application, the usefulness of biofeedback for psychiatric research is discussed. Physiological measurements obtained during the treatment of headache patients with EMG feedback now question the well-known theory of increased muscle tension as the mechanism of tension headaches. Moreover, biofeedback can be regarded as a well defined psychotherapeutic context allowing the quantification of some psychophysiological effects of therapist-patient relationships.