e4-09: Biofeedback

Biofeedback is a behavioral therapy method that teaches a patient to gain greater awareness and control over physiologic functions, including some not normally under conscious control. This is achieved by using technology that presents to the patient in visual or auditory form the level of activity of a physiologic parameter, such as muscle tension, skin temperature, sweat gland activity, respiratory muscle activity, PCO₂, heart rate variability, or brain wave pattern.

Biofeedback began in the 1950s with the work of the experimental psychologist Dr. Neil Miller. He demonstrated that rats could learn to regulate autonomic functions when motivated by painful or pleasurable stimuli. The idea that autonomic function could be volitionally controlled was contrary to the scientific dogma of the time. In the 1960s, other researchers began to examine the human ability to consciously alter physiologic function.

Certification is obtained through the Biofeedback Certification International Alliance (BCIA) and is open to professionals from clinical health care areas including, but not limited to, psychology, nursing, and counseling. Requirements for certification are: (1) 48 hours of didactic education; (2) 20 hours of contact spent with a BCIA-approved mentor, 50 patient/client sessions, and case conference presentations; and (3) successful completion of a written certification examination. There is also a continuing education requirement.

When treating a medical or psychological disorder, biofeedback practitioners must hold a current state license in a BCIA-approved health care field or, if without this license, be supervised by an appropriately credentialed health care professional. Separate, additional certificates are required for electroencephalographic (EEG) biofeedback (neurofeedback) and pelvic muscle dysfunction work.

The goal of biofeedback is to help the patient train himself or herself to produce the desired response at other times. Since biofeedback is a taught, self-regulatory skill, patients should be motivated; prepared to take an active role in their treatment; able to respond well to visible, quantifiable information; or have aptitude or familiarity with technology. Typical biofeedback sessions last 50 minutes, with half or more of that time in active monitoring. To begin a biofeedback session, the therapist applies sensors to the patient that monitor the physiologic parameters of interest. For example, in a case of chronic tension headache, an electromyographic (EMG) sensor may be applied to the skin of the forehead. Information from the sensor feeds back to the patient as sound or as an image on a computer screen in real time, so he or she can begin to learn to reduce tension in the forehead muscle. Multiple sessions are usually required, and the patient is asked to practice the learned skills between sessions. Some biofeedback software programs and sensors are available for use on a home computer or with portable electronic devices.

There are no reported adverse effects of biofeedback therapy. Benzodiazepines, opioids, other sedating medicines, and even caffeine can have undesirable effects on biofeedback training.

A. Hypertension

The AHA 2013 Scientific Statement paper on CIT for blood pressure–lowering conferred a "Class IIB, level of evidence B" designation for the efficacy of biofeedback for treating hypertension and stated that "biofeedback may be considered in clinical practice to lower blood pressure." Studies on the blood pressure–lowering effect of biofeedback have been published for over 40 years. Meta-analyses consistently show that compared with waitlist or other inactive control groups, biofeedback can significantly lower patients' systolic and diastolic blood pressures (approximately 5–8 mm Hg systolic and 3–5 mm Hg diastolic pressure). In many older studies biofeedback was not superior to an active control group (eg, sham biofeedback or nonspecific behavioral control) in its effect on blood pressure except when coupled with relaxation training or cognitive therapy. But later studies suggest that biofeedback is superior to active controls, achieving significantly greater blood pressure reductions and increased baroreceptor sensitivity. In general, the degree of blood pressure reduction with biofeedback strongly correlates with pretest blood pressure, ie, persons with higher baseline blood pressures show larger beneficial effects.

Because most patients in studies of nonpharmacologic treatment of hypertension have only mild hypertension, the effect of treatments like biofeedback are more difficult to detect. Also, as for all antihypertensive therapies, small reductions in blood pressure yield important clinical benefits.

There is also research on respiratory biofeedback training for blood pressure reduction. A particular pattern of device-assisted respiration practiced for 15 minutes daily has been shown in seven of nine small studies to lower ambulatory blood pressure. A meta-analysis of eight studies concluded that both diastolic and systolic blood pressure may be reduced with short-term use of device-guided breathing. However, following exclusion of five of the trials, which were sponsored by or involved the manufacturers of the device, no significant effect was found. A 2015 review of 15 published studies of this device concluded that it does significantly lower blood pressure (but one of the review's authors may have had a financial conflict of interest). Longer term, independent trials are required.

B. Coronary Artery Disease

Heart rate variability is an indicator of autonomic tone and is postulated to be the mediator of the effects of cognitive and mind-body therapies on cardiovascular conditions. Cardiac electrophysiology studies have shown that decreased heart rate variability is predictive of both short-term and long-term mortality after MI. There are several clinical studies of the effect of biofeedback on heart rate variability. One RCT of 154 patients with established CAD showed that biofeedback significantly increased heart rate variability. A second RCT by the same group involving 222 patients found fewer all-cause readmissions and all-cause emergency visits (13.33 versus 35.59%) than the control group at 1 year follow-up Another RCT showed an 86% reduction in post-MI mortality at 2 years after a psychosocial intervention that included biofeedback training of heart rate variability. However, this study did not show a significant change in heart rate variability except with exclusion of individuals with baseline high heart rate variability. Thus, it is not yet established that improved heart rate variability from biofeedback training affects important cardiovascular outcomes.

C. Raynaud Phenomenon

The efficacy of biofeedback on Raynaud phenomenon has been studied in eight RCTs. Three show biofeedback to be superior to active control (eg, autogenic training), and four show benefit from biofeedback that is equivalent to active control. One large study showed thermal biofeedback to be equivalent to EMG biofeedback treatment and to treatment with sustained-release nifedipine.

D. Headache

The efficacy of biofeedback and other behavioral techniques on recurrent migraine and tension headaches has been evaluated in over 50 studies including many RCTs. Several meta-analyses concur there is a significant reduction (30–55%) in headache frequency with biofeedback and other behavioral interventions. Other outcomes with significant improvement in several headache studies are anxiety, depression, self-efficacy, and medication usage. The American Academy of Neurology practice guidelines state that there is grade A evidence for the use of thermal biofeedback with relaxation or EMG biofeedback for prevention of migraine. Biofeedback compares favorably with pharmaceutical treatments in several studies. There are also studies showing enhanced efficacy from adding medications to biofeedback therapy. The American Academy of Neurology practice guidelines state that there is grade B evidence for behavioral therapy (eg, biofeedback and relaxation techniques) when combined with prophylactic medication therapy (eg, propranolol and amitriptyline) to achieve additional clinical improvement for migraine relief. Finally, a 2016 randomized controlled pilot study of 27 patients suggested that biofeedback may have a role in treating medication-overuse headache.

E. Urinary Incontinence

Pelvic floor muscle training is an effective treatment for incontinence in women. In a 2011 Cochrane review of 24 trials, biofeedback-assisted pelvic floor muscle training yielded higher benefit for incontinence in women, but a 2012 review questioned whether the observed effect could be related to the amount of health professional contact. A 2013 RCT supported the use of biofeedback for urinary incontinence in premenopausal women. In 2016, an RCT involving 58 women with overactive bladder symptoms showed significantly improved symptoms and quality of life with EMG biofeedback-assisted pelvic muscle therapy after 9 weeks of treatment. In men with urinary incontinence after prostatectomy, a 2016 systematic review and meta-analysis of 13 RCTs involving a total of 1108 patients found that biofeedback-assisted pelvic floor muscle training resulted in immediate-, intermediate-, and long-term benefits on urinary incontinence that were significantly better than pelvic floor muscle training alone. Small-to-moderate immediate- and intermediate-term effects were also observed on the quality of life. A 2012 RCT of 52 post-prostatectomy men showed that pelvic floor biofeedback significantly improved erectile function.

F. Fecal Incontinence

There are over 40 trials of biofeedback for fecal incontinence in adults. Although all but two of these reported moderate to large benefit, the methodologic quality of some studies is low. A 2012 Cochrane review of biofeedback and sphincter exercises for fecal incontinence that included 21 RCTs found that biofeedback appeared to improve treatment outcomes; however, due to methodological weaknesses of many of the trials, a definitive conclusion was not possible. A 2013 systematic review of 13 trials was more positive, noting that biofeedback plus electrical stimulation was particularly effective. A report of 513 consecutive patients seen at a tertiary colorectal referral clinic showed that over 70% of patients received benefit. Skeptics have noted that most studies of biofeedback for fecal incontinence were performed in tertiary referral centers that had specialized expertise in this modality. However, a 2017 retrospective study form a secondary care center found low-intensive biofeedback therapy in 205 patients achieved results comparable to those at tertiary referral centers (71% patient response rate; 47% achieved continence). Good anal sphincter exercise technique, longer in-home practice, and more sessions were significantly associated with a favorable outcome. Another real-world study in 2013 found that less than half of patients with fecal incontinence referred for pelvic biofeedback actually received this therapy due to lack of insurance coverage or geographic distance to the treatment facility; however, the success rate was high (80%) in those who did receive biofeedback therapy. Another 2013 trial found significant quality of life benefit for fecal incontinence patients undergoing biofeedback therapy. In addition to the many clinicians in this field who consider pelvic biofeedback to be first- or second-line therapy for fecal incontinence, the American College of Gastroenterology Practice Guidelines consider recommend it as safe and effective for the treatment of fecal incontinence.

G. Chronic Constipation

Approximately 30–50% of cases of chronic constipation are due to pelvic floor dyssynergia, in which there is a failure of the pelvic floor and anal muscles to relax during straining. Constipation due to pelvic floor dyssynergia is less response to laxative and fiber treatment but may be successfully treated with biofeedback. In 6 of 11 RCTs of patients with pelvic dyssynergia, biofeedback was superior to other modalities, including usual care, polyethylene glycol, diazepam, placebo, or sham biofeedback, achieving success rates of 70-80%. A 2012 report of 226 patients referred to a tertiary care center also showed that over two-thirds of patients with dyssynergic defecation had improved symptoms with pelvic biofeedback therapy. In an RCT of 157 with levator ani syndrome, a condition related to dyssynergia, response to biofeedback was superior to pelvic floor massage or electrostimulation. Based on its demonstrated efficacy and safety, biofeedback is widely recommended as first-line therapy alone or in combination with other measures for pelvic floor dyssynergia.

H. Stroke Rehabilitation

Biofeedback for stroke rehabilitation has a sound theoretical basis but has been difficult to evaluate for several reasons, including nonstandardized outcome measures, multiple versions of biofeedback therapies, and variability in the time poststroke at which biofeedback is offered. There are over 30 RCTs, all with small sample sizes. Although most studies show some benefits, such as improved motor strength, gait quality, and functional recovery, overall results are mixed. A Cochrane review concluded that EMG biofeedback cannot be recommended as a routine treatment but may be reasonably considered due to its safety and possible efficacy. A comprehensive 2009 review on motor recovery following stroke pointed out the limitations of trials of biofeedback for stroke but concluded that there are positive results for recovery of arm function and standing balance but not for sit-to-stand transfer ability. At least four trials have concluded that there is significant benefit of biofeedback for gait training after stroke. A 2013 RCT showed improvement in hand function with biofeedback, and a 2014 RCT showed improvement in lower extremity function. In two 2016 trials, visual biofeedback did not enhance outcomes of gait symmetry and postural balance beyond what was achieved with conventional treadmill training and physical therapy. In a trial conducted in patients with poststroke dysphagia, laryngeal elevation training combined with game-based biofeedback increased the removal rate of nasogastric tubes.

I. Psychiatric Disorders

EEG biofeedback, also known as neurofeedback, was first used to reduce seizure frequency in epilepsy in the 1970s. Since then, it has been applied to psychoses, substance use disorders, anxiety disorders, affective disorders, traumatic brain injury, attention-deficit/hyperactivity disorders, and other psychiatric conditions. However, there are few methodologically rigorous trials investigating this form of biofeedback in adults. A 2012 case series report of 51 patients with schizophrenia showed neurofeedback led to improvements in the Positive and Negative Syndrome Scale score in most patients. A 2016 RCT of 84 patients with psychotic symptoms who underwent heart rate variability biofeedback sessions showed that no group differences occurred in paranoid symptoms or subjective stress, although paranoia was diminished in the subset of participants who were breathing per protocol. A small 2013 RCT of 20 people with opiate addiction undergoing neurofeedback showed improvement in somatic symptoms, mental health, relief from withdrawal, and reduced desire to use opioids. A 2016 review of neurofeedback for PTSD examined five studies and found that neurofeedback had a statistically significant effect in three studies.