A Double‐Blind Methodology for Biofeedback Research

A number of investigators have suggested that the beneficial effects attributed to biofeedback (BF) might be due, in part, to placebo factors. The double‐blind design is well‐suited to test this hypothesis; however, the major difficulty has been to devise a system to present undetectable placebo BF and simultaneously keep the experimenter “blind” while he conducts BF training in his normal fashion. The system described accomplished this objective when tested on 29 opiate addicts who received 14 sessions of contingent or noncontingent EEG/EMG BF training for symptom reduction during detoxification. The 4 experimenters could not determine subject status at better than chance levels, and the 29 addicts were equally unsuccessful in determining their own status. Although contingent subjects demonstrated more control over EMG activity, no difference in therapeutic outcome was observed between the groups under double‐blind conditions. These findings demonstrate that the procedures used to implement the double‐blind biofeedback system were highly effective, and that the integrity of the system was maintained under clinical treatment conditions.