Does training to criterion influence improvement? A follow-up study of EMG and thermal biofeedback.

On follow-up 1 to 5 years after therapy, patients in six diagnostic groups who received EMG (N = 53) and/or thermal (N = 54) biofeedback and who reached criterion levels (EMG less than or equal to 1.1 microV; thermal greater than or equal to 95 degrees F) reported a higher improvement rate than those who had not achieved these criterion levels. Neither the patients nor the therapist were aware of these training criteria during therapy. Most patients received both EMG and thermal biofeedback training. Of the EMG achievers, 93% improved, compared to 65% of the nonachievers. Of the thermal achievers, 96% improved, compared to 76% of the nonachievers. These percentages significantly exceed the high base rate (81%) of long-term improvement in this study. Failure to achieve the criterion level in both modalities was associated with a lower improvement rate (73% did not improve), while achieving the criterion in only one modality was sufficient to be associated with improvement. Of the patients who did not improve, 80% had not achieved the EMG criterion, and 88% had not achieved the thermal training criterion. These results question biofeedback therapy outcome studies which slow low improvement rates without determining whether self-regulation skills had, in fact, been acquired.