• ]]>High Blood Pressure]]>
• ]]>Anxiety]]>, ]]>Back Pain]]>, ]]>Constipation]]>, Female Stress Incontinence, ]]>Insomnia]]>, Headaches ( ]]>Migraine]]> and ]]>Tension]]> ) , Pain in General (Many Types), ]]>Raynaud's Disease]]>, Rehabilitation from ]]>Strokes]]>, ]]>Stress]]>, ]]>Tension-type Headaches]]>
Some functions in the body occur automatically, outside of conscious control (such as heart rate and blood pressure). Biofeedback is a method of making those “involuntary” processes something you can do at will.
The basic method is quite simple. In biofeedback, a machine gives you direct information regarding the bodily process in question (the “feedback” part of the term “biofeedback”). Given this information, you can find a way to control it, just like you can learn to wiggle your ears if you try hard enough.
For example, your blood pressure might be displayed on a screen. Blood pressure naturally goes up and down from time to time. When it goes down, you’ll notice that and feel pleased; when it goes up, you’ll feel displeased. Pleasure and displeasure act like the reward and punishment technique used for training animals. When a rat in a maze is rewarded with food for going the right way and given an electric shock for going the wrong way, it will soon learn to go the right way. Similarly, the unconscious parts of the nervous system figure out a way to get a "reward" instead of receive "punishment." In the case just described, this means reducing blood pressure.
The display screen provides the feedback because normally we can’t detect our own blood pressure. Using a machine to provide that information allows the person to achieve conscious control. This process generally works, at least to a modest extent. After a number of sessions, most people reach a place where they can lower their blood pressure simply by thinking, “I want my blood pressure to fall.” They don’t know how they're doing it (any more than ear wigglers know how they’ve accomplished that); nonetheless, they can cause the desired effect.
In addition to measuring blood pressure and heart rate, there are biofeedback machines in fairly common use that measure muscle tension, skin temperature, skin resistance to electricity, and brain wave activity.
What Is Biofeedback Used For?
Probably the most common use of biofeedback is to treat stress]]> and stress-related conditions, including ]]>anxiety]]> , ]]>insomnia]]> , ]]>high blood pressure]]> , ]]>fibromyalgia]]> , muscle pain, ]]>migraine headaches]]> , and ]]>tension headaches]]> .
What Is the Scientific Evidence for Biofeedback?
Although many studies have evaluated biofeedback, most of them suffer from inadequate design. 1]]> Only one form of study can truly prove that a treatment is effective: the ]]>double-blind, placebo-controlled trial]]> . (For more information on why such studies are so crucial, see ]]>Why Does This Database Rely on Double-blind Studies?]]> )
However, it is somewhat tricky to fit biofeedback into a study design of this type. The main problem is finding a placebo for biofeedback treatment. In the best-designed studies of biofeedback, people in the placebo group practice biofeedback with a machine that produces carefully garbled information. Study participants in this group believe they are practicing biofeedback, but in fact they are not learning any conscious control over the body process in question.
Many biofeedback studies do not use placebo biofeedback; they compare biofeedback to no treatment. Studies of this type cannot provide reliable evidence about the efficacy of a treatment. If a benefit is seen, there is no way to determine whether biofeedback caused it or whether it was caused generically by attention. (Attention alone will almost always produce some reported benefit.)
Other trials used intentionally neutral therapies, such as the use of a home diary. These are better than studies with a no-treatment control group. However, when the placebo is so different in form than the treatment under study, any apparent differences in outcome could simply represent differences in the power of suggestion in each approach.
Still other studies simply involved giving people biofeedback and seeing whether they improved. Such trials are almost completely meaningless; numerous studies have shown that both participants and examining physicians will frequently think they observe improvement in people given a treatment, regardless of whether the treatment does anything on its own. For example, early studies of biofeedback for stroke rehabilitation that did not use blinding or a control group reported miraculous successes equivalent to the “throw down your crutches and walk” cliché. ]]>2]]> However, when controlled trials were performed, it turned out that biofeedback did not provide much more than marginal benefit, if any. For this reason, we do not even report uncontrolled studies below.
Given these caveats, the following is a summary of what science knows about the medical benefits of biofeedback.
Possible Effects of Biofeedback
Of all the medical conditions for which biofeedback has been advocated, the best studied is ]]>hypertension]]> . However, a review of the literature published in 2003, which found 22 controlled trials of acceptable quality, ]]>3]]> concluded that real biofeedback is not more effective than fake biofeedback. A study published subsequent to this review did report benefits, but it was poorly designed. ]]>24]]>
Biofeedback has been studied for other medical conditions as well. At least one controlled study supports the use of biofeedback for each of the following: ]]>anxiety]]> , ]]>12]]> chronic low-back pain, ]]>13]]> female stress incontinence, ]]>14]]>]]>insomnia]]> , ]]>5]]> and, possibly, rehabilitation from ]]>strokes]]> . ]]>18-20]]> Note that the evidence of benefit with biofeedback is not definitive for any of these conditions, and in many cases there are also studies with negative outcomes.
There is mixed evidence for the effectiveness of biofeedback for recurrent headaches, both ]]>migraine]]> and ]]>tension]]> . ]]>15-17]]> In a detailed review of multiple controlled studies, however, researchers concluded that biofeedback is useful for tension headaches, particularly when combined with other relaxation therapies. ]]>25]]> And, in another review of 94 studies, researchers concluded that biofeedback is capable of significantly reducing the frequency for both migraine and tension-type headaches, among other benefits. ]]>27]]> However, it is important to note that not all of the studies they used to arrive at this conclusion were randomized, placebo-controlled trials.
The balance of the evidence suggests that biofeedback is not effective for ]]>asthma]]> , ]]>7]]> and no more than marginally effective for ]]>Raynaud’s disease]]> . ]]>10,11]]> Evidence is mixed regarding biofeedback’s effectiveness for ]]>constipation]]> . ]]>8-9,21,23-24,28]]> However, a detailed review of 3 randomized trials found that biofeedback was more effective than non-biofeedback treatments for constipation related to pelvic floor dysfunction, though the studies were not of the highest quality. ]]>26]]>
What to Expect During a Biofeedback Session
As described above, biofeedback training involves the use of a machine that relays information about the aspect of the body that you wish to control. In early stages, the trick is finding the “muscles” necessary to produce the desired effect. Typically, a biofeedback practitioner will teach a series of visualizations and other mental exercises in the hope that it will facilitate the process. For example, if you have high blood pressure, you might be asked to imagine the blood vessels in your body opening up and dilating.
How to Choose a Biofeedback Practitioner
As with all medical therapies, it is best to choose a licensed practitioner in states where a biofeedback license is available. Where licensure is not available, seek a referral from a qualified and knowledgeable healthcare provider.
10. Raynaud's Treatment Study Investigators. Comparison of sustained-release nifedipine and temperature biofeedback for treatment of primary Raynaud’s phenomenon. Results from a randomized clinical trial with 1-year follow-up. Arch Intern Med. 2000;160:1101-1108.
24. Tsai PS, Chang NC, Chang WY, et al. Blood pressure biofeedback exerts intermediate-term effects on blood pressure and pressure reactivity in individuals with mild hypertension: a randomized controlled study. J Altern Complement Med. 2007;13:5:547-554.
Last reviewed September 2009 by EBSCO CAM Medical Review Board]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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