Biofeedback training of cardiac acceleration; effects on airway resistance in bronchial asthma

Twenty-four volunteers adolescent and adult asthmatics were pre-tested for suggestibility and retained for an investigation of the airway effects of biofeedback induced voluntary cardiac acceleration. Eight subjects were successful in achieving large magnitude voluntary cardiac acceleration after 2-5 training sessions. Eight matched control group subjects received one session of biofeedback assisted training in cardiac constancy. Results revealed that large magnitude heart rate increase was accompanied by a statistically significant increase in Peak Expiratory Flow Rate for experimental group subjects. Control group subjects showed a drop in heart rate and a statistically insignificant drop in PEFR. Clinical records for experimental and control group subjects during the pre- and post-training periods revealed that a significant reduction in the incidence of attacks, the use of p.r.n. medication, and the index of medication use per attack occurred in trained subjects. No change on any of these criteria occurred for control group subjects. The acquisition of the cardiac acceleration response of asthmatic experimental group subjects was compared with the acquisition rate of a matched group of normal subjects receiving one session of biofeedback training. No differences were revealed between the groups in the rate of acquisition. However, symptom-free asthmatics were shown to have PEFR readings significantly below those of the normal group, thus supporting previous findings. The possible implications of these findings for the clinical management of bronchial asthma, are discussed.