Abstract
Biofeedback is defined as a group of nonpharmacological therapeutic procedures that use electronic instruments to measure. process, and provide information to patients regarding their neuromuscular and autonomic nervous system activity in the form of analogue (or binary) and visual (or auditory) signals. Recent technical improvements in blood pressure monitoring and data processing make biofeedback more reliable and comfortable to apply for the treatment of hypertension. In the present study, a meta analysis was conducted to examine treatment effects of biofeedback on lowering blood pressure of essential hypertension. A total of 22 randomized controlled studies with 905 essential hypertensive patients were selected for review. When biofeedback intervention was compared with sham or non specific behavioral control intervention, the net reductions in systolic and diastolic blood pressures were 3.9 [95% confident interval, [-0.3 to 8.2] and 3.5 [-0.1, 7.0] mmHg, respectively. Compared with clinical visits or self monitoring of blood pressure (non intervention control), the degrees of reductions in systolic and diastolic blood pressures were significantly greater in the biofeedback intervention by 7.3 [2.6, 12.0] and 5.8 [2.9, 8.6] mmHg, respectively. When biofeedback intervention types were classified into the simple biofeedback group and relaxation assisted biofeedback group, only the relaxation-assisted biofeedback group showed significant decreases in both systolic and diastolic blood pressures, compared with sham or non specific behavioral control trials (p<0.05). The results suggested that biofeedback was superior to sham or non specific behavioral intervention when combined with other relaxation therapies in essential hypertension, whereas biofeedback alone was more effective in reducing blood pressure than no intervention control. At the present stage, it is still inconclusive that biofeedback itself has anti hypertensive effect beyond the placebo effect or "remembered wellness". Future studies are needed to clarify the specific psychological and physiological mechanisms of biofeedback treatment.
