Biofeedback Research

C 2023

Biofeedback mechanism.
Biofeedback is a form of alternative medicine that involves measuring a subject bodily processes such as blood pressure, heart rate, skin temperature, galvanic skin response (sweating), and muscle tension and conveying such information to him or her in real-time in order to raise his or her awareness and conscious control of the related physiological activities.
By providing access to physiological information about which the user is generally unaware, biofeedback allows users to gain control over physical processes previously considered automatic. Interest in biofeedback has waxed and waned since its inception in the 1960s; at the beginning of the 21st century it is undergoing something of a renaissance, which some ascribe to the general upswing of interest in alternative medicine modalities. Neurofeedback has become a popular treatment for ADHD; electromyogram (muscle tension) biofeedback has been widely studied and accepted as a treatment for incontinence disorders, and small home biofeedback machines are becoming available for a variety of uses. Its role in controlling hypertension is becoming recognized [1].
Types of biofeedback instrumentation

Electromyogram (EMG)
An Electromyogram is the most common form of biofeedback measurement. An EMG uses electrodes or other types of sensors to measure muscle tension. By the EMG alerting you to muscle tension, you can learn to recognize the feeling early on and try to control the tension right away. EMG is mainly used as a relaxation technique to help ease tension in those muscles involved in backaches, headaches, neck pain and grinding your teeth (bruxism). An EMG may be used to treat some illnesses in which the symptoms tend to worsen under stress, such as asthma and ulcers.
Peripheral skin temperature
Sensors attached to your fingers or feet measure your skin temperature. Because body temperature often drops when a person experiences stress, a low reading can prompt you to begin relaxation techniques. Temperature biofeedback can help treat certain circulatory disorders, such as Raynaud’s disease, or reduce the frequency of migraines. The physiological process behind the temperature drop associated with the stress response is quite simply vasoconstriction (blood vessels narrowed by the smooth musculature in their walls)
Galvanic skin response training
With Galvanic skin response training, sensors measure the activity of your sweat glands and the amount of perspiration on your skin alerting you to anxiety. This information can be useful in treating emotional disorders such as phobias, anxiety and stuttering. This is the method most commonly used by lie detector machines. It is the most popular form of biofeedback, with over 500,000 hand-held GSR2 units having been purchased by consumers since the early ’70s; it is also one of the biofeedback methods used by Calmlink and the video game series Journey to Wild Divine. Galvanic Skin Response meters are also now gaining popularity in hypnotherapy and psychotherapy practice where subtle physiological changes indicating emotional arousal can be more easily detected than by observation alone.

Electroencephalography (EEG)
An EEG monitors the activity of brain waves linked to different mental states, such as wakefulness, relaxation, calmness, light sleep and deep sleep. This is the least common of the methods, mostly due to the cost and availability of an EEG machine.
Neal Miller, a psychology Ph.D and neuroscientist who worked and studied at Yale University, is generally considered to be the father of modern-day biofeedback. He came across the basic principles of biofeedback while doing animal experimentation conditioning the behavior of rats. His team found that, by stimulating the pleasure center of a rat’s brain with electricity, it was possible to train them to control phenomena ranging from their heart rates to their brainwaves. Until that point, it was believed that bodily processes such as heart rate were under the control of the autonomic nervous system and not responsive to conscious effort[2].
The Miller group was one of three major approaches to understanding the limits of self-regulation of the body. Voluntary control of the autonomic nervous system had been considered impossible, only controlled by conditioning. Other threads of inquiry leading to biofeedback emerged from clinical attempts to use mind/body self-regulation techniques in healthcare. Elmer Green, PhD of the Menninger Foundation produced some of the original research on the limits of human self-regulation of normally unconscious processes and applied these techniques successfully to migraine headache and hypertension. Barbara Brown, PhD actually coined the word “biofeedback” during the early days of the field, as the Biofeedback Research Society was being formed. Other early pioneers were interested in consciousness and looked at EEG self-regulation as a way to approach mind vs. brain distinctions – see the work of Joe Kamiya, PhD. Other early efforts were directed toward examining the claims of yogis and other meditators for demonstrated mind/body control and markers of states of consciousness.[3] See Elmer Green et al Beyond Biofeedback and Barbara Brown Stress & The Art of Biofeedback for some early writings. The Biofeedback Research Society evolved into the Biofeedback Society of America and more recently the Association for Applied Psychophysiology and Biofeedback, a scientific and professional society for the field.

Hemoencephalography (HEG)
An HEG is a method of functional infrared imaging that indirectly measures neural activity in the brain. There are two known types of HEG, passive infrared (pIR) and near infrared (nIR).[4] Near Infrared HEG relies on the measurement of the differences in the color of light being reflected back through the scalp by the relative amount of oxygenated and unoxygenated blood in the the brain. Passive Infrared relies on the measurement of the heat being radiated from the scalp at locations of interest.

Biofeedback Overview, By Mayo Clinic
Biofeedback is a technique you can use to learn to control your body’s functions, such as your heart rate. With biofeedback, you’re connected to electrical sensors that help you receive information (feedback) about your body (bio).

This feedback helps you focus on making subtle changes in your body, such as relaxing certain muscles, to achieve the results you want, such as reducing pain. In essence, biofeedback gives you the power to use your thoughts to control your body, often to improve a health condition or physical performance.

Types of biofeedback

Your therapist might use several different biofeedback methods. Determining the method that’s right for you depends on your health problems and goals. Biofeedback methods include:

Brainwave. This type of method uses scalp sensors to monitor your brain waves using an electroencephalograph (EEG).
Breathing. During respiratory biofeedback, bands are placed around your abdomen and chest to monitor your breathing pattern and respiration rate.
Heart rate. This type of biofeedback uses finger or earlobe sensors with a device called a photoplethysmograph or sensors placed on your chest, lower torso or wrists using an electrocardiograph (ECG) to measure your heart rate and heart rate variability.
Muscle. This method of biofeedback involves placing sensors over your skeletal muscles with an electromyography (EMG) to monitor the electrical activity that causes muscle contraction.
Sweat glands. Sensors attached around your fingers or on your palm or wrist with an electrodermograph (EDG) measure the activity of your sweat glands and the amount of perspiration on your skin, alerting you to anxiety.
Temperature. Sensors attached to your fingers or feet measure your blood flow to your skin. Because your temperature often drops when you’re under stress, a low reading can prompt you to begin relaxation techniques.
Biofeedback devices

You can receive biofeedback training in physical therapy clinics, medical centers and hospitals. A growing number of biofeedback devices and programs are also being marketed for home use, including:

Interactive computer or mobile device programs. Some types of biofeedback devices measure physiological changes in your body, such as your heart rate activity and skin changes, by using one or more sensors attached to your fingers or your ear. The sensors plug into your computer.

Using computer graphics and prompts, the devices then help you master stress by pacing your breathing, relaxing your muscles and thinking positive thoughts. Studies show that these types of devices might be effective in improving responses during moments of stress, and inducing feelings of calm and well-being.

Another type of biofeedback therapy involves wearing a headband that monitors your brain activity while you meditate. It uses sounds to let you know when your mind is calm and when it’s active to help you learn how to control your stress response. The information from each session can then be stored to your computer or mobile device.

Wearable devices. One type of wearable device involves wearing a sensor on your waist that monitors your breathing and tracks your breathing patterns using a downloadable app. The app can alert you if you’re experiencing prolonged tension, and it offers guided breathing activities to help restore your calm.
The Food and Drug Administration has approved a biofeedback device, Resperate, for reducing stress and lowering blood pressure. Resperate is a portable electronic device that promotes slow, deep breathing.

However, many biofeedback devices marketed for home use aren’t regulated by the Food and Drug Administration. Before trying biofeedback therapy at home, discuss the different types of devices with your doctor to find the best fit.

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What are the published researches supporting Biofeedback?

The following published research articles support the general science of biofeedback and its applications as effective therapies for a host of clinical ailments:

Biofeedback in the Treatment of Phantom Limb Pain: A Time Series Analysis. Retrieved September 3, 2010 from

Summary: Researchers at the Center for Pain Studies located in the Rehabilitation Institute of Chicago / Northwestern University Medical School performed a study of nine individuals with Phantom Limb Pain to assess the effects of biofeedback on pain. The participants received biofeedback treatments over the course of four to six weeks. The results of the study showed that eight of the nine patients experienced reductions in pain that varied from 25-66 percent.

Biofeedback in the Treatment of headache and other Childhood Pain. Retrieved September 3, 2010 from

Summary: Much research has been conducted on the subject of the effects of biofeedback on childhood pain, mainly headaches. Empirical data was studied and reassessed by researchers at both the Central Institute of Mental Health in Mannheim, Germany and the Center for Stress and Anxiety Disorders in Albany, New York. The findings have shown evidence that approximately two thirds of the children experienced a 50% pain decrease regarding headaches. The studies concerning biofeedback on related pain such as arthritis and recurrent abdominal pain have shown to be inconclusive due to a lack of research.

Biofeedback for Chronic Obstructive Pulmonary Disease in the Treatment of headache and other Childhood Pain. Retrieved September 3, 2010 from

Summary: A study done was conducted at the University of Washington Medical Center to test the likelihood of an intervention that included heart rate variability biofeedback and walking with pulse oximetry feedback to improve quality of life for patients suffering from chronic obstructive pulmonary disease. Twenty participants were studied over the course of nine sessions using the Six Minute Walk Distance Test. Outcomes. The outcome showed a statistically and clinically significant improvement in walking distance and overall quality of life.

Biofeedback of R-Wave-to-Pulse Interval Normalizes Blood Pressure. Retrieved September 3, 2010 from

Summary: Doctors in Munich, Germany explored the way biofeedback treatment affected patients with problematic blood pressures. Twenty-two participants received three individual sessions over the course of two weeks. Twelve of the participants had high blood pressure while the other ten experienced low pressures. The findings concluded that both high and low pressures were modified in a significant and positive way after three sessions of biofeedback.

Biofeedback Treatment for Asthma. Retrieved September 3, 2010 from

Summary: Research was conducted at the University of Medicine and Dentistry of New Jersey and the Robert Wood Johnson Medical School to evaluate the effectiveness of biofeedback as a complimentary treatment for asthma. Ninety-four adult volunteers with asthma participated. Results suggested that the participants required less steroid medications and averaged a decrease in one full level of asthma severity.

Comparison of the Efficacy of Electroencephalography, Cognitive-Behavioral Therapy and Conservative Medical Interventions in the Treatment of Chronic Musculoskeletal Pain. Retrieved September 3, 2010 from

Summary: Researchers at the University of Tubingen in Germany compared three different types of treatments for chronic musculoskeletal pain to evaluate which would be most effective. The treatments compared were EMG biofeedback, cognitive-behavioral therapy, and conservative medical treatment. At the 24-month follow-up, only the biofeedback group maintained significant reductions in pain severity.

Biofeedback for Hypertension. Retrieved September 3, 2010 from

Summary: The Health and Public Policy Committee has reported that biofeedback is a constructive tool to decrease the use of medication in patients with hypertension. The research is based on 10-20 thirty-minute sessions, which have been proven to lessen blood pressure levels.

Biofeedback-Assisted Relaxation in Migraine Headache: Relationship to Cerebral Blood Flow Velocity in the Middle Cerebral Artery. QBAA Published Research. Retrieved September 3, 2010 from

Summary:Summary: The departments of Psychiatry and Neurology at the Medical College of Ohio tested 20 patients experiencing migraines with and without auras. After being treated with 20 sessions of biofeedback the patients experienced a reduction in pain, depression, and anxiety. Patients with and without aura experienced equally positive outcomes.

Evaluating the Efficacy of a Biofeedback Intervention to Reduce Children ADD. Retrieved September 3, 2010 from

Summary: Over a six-week period, 150 7th and 8th grade children with high anxiety were assigned to 12 sessions of biofeedback to determine if the treatments would aid in a reduction of symptoms. Students received six sessions of thermal training and six sessions of EMG training. The research showed that there was a significant decline in both state and trait anxiety.

Biofeedback in Treatment of Heart Failure. Retrieved September 3, 2010 from

Summary: Biofeedback training can be used to reduce activation of the sympathetic nervous system (SNS) and increase activation of the parasympathetic nervous system (PNS). It is well established that hyperactivation of the SNS contributes to disease progression in chronic heart failure. It has been postulated that underactivation of the PNS may also play a role in heart failure pathophysiology. In addition to autonomic imbalance, a chronic inflammatory process is now recognized as being involved in heart failure progression, and recent work has established that activation of the inflammatory process may be attenuated by vagal nerve stimulation. By interfering with both autonomic imbalance and the inflammatory process, biofeedback-assisted stress management may be an effective treatment for patients with heart failure by improving clinical status and quality of life.

Recent studies have suggested that biofeedback and stress management have a positive impact in patients with chronic heart failure, and patients with higher perceived control over their disease have been shown to have better quality of life. Our ongoing study of biofeedback-assisted stress management in the treatment of end-stage heart failure will also examine biologic end points in treated patients at the time of heart transplant, in order to assess the effects of biofeedback training on the cellular and molecular components of the failing heart. We hypothesize that the effects of biofeedback training will extend to remodeling the failing human heart, in addition to improving quality of life.

Biofeedback for Headaches. Retrieved September 3, 2010 from

Summary: Biofeedback is a direct feedback of a physiological function. The aim of biofeedback is to change the physiological function into a required direction. To manage this, the physiological function has to be fed back visually or acoustically and it has to be perceived consciously. Biofeedback as a therapeutic practice derives from behavioural therapy and can be used in the context of behavioural interventions. Biofeedback has proved to be successful in non-medical treatment of pain. According to more recent meta-analyses biofeedback reveals high evidence in the treatment of migraine or tension-type headache. In these headaches biofeedback procedures are considered highly effective. PMID: 20563685 [PubMed – in process] Dr. George Grant has been our keynote speakers at our annual convention for the past 10 years.
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Virtual reality in the treatment of generalized anxiety disorders. Retrieved September 3, 2010 from

Generalized anxiety disorder (GAD) is a common anxiety disorder characterized by 6 months of excessive anxiety and worry about a variety of events and situations. Anxiety and worry are often accompanied by additional symptoms like restlessness, being easily fatigued, difficulty concentrating, irritability, muscle tension and disturbed sleep. GAD is usually treated with medications and / or psychotherapy. In particular, the two most promising treatments seem to be cognitive therapy and applied relaxation. In this study we integrated these approaches through the use of a biofeedback enhanced virtual reality (VR) system used both for relaxation and controlled exposure.

Moreover, this experience is strengthened by the use of a mobile phone that allows patients to perform the virtual experience even in an outpatient setting. This paper describe the results of a controlled trial (NCT00602212) involving 20 GAD patients randomly assigned to the following groups: (1) the VR and Mobile group (VRMB) including biofeedback; (2) the VR and Mobile group (VRM) without biofeedback; (3) the waiting list (WL) group. The clinical data underlined that (a) VR can be used also in the treatment of GAD; (b) in a VR treatment, patients take advantage of a mobile device that delivers in an outpatient setting guided experiences, similar to the one experienced in VR.

Prolonged Electromyogram Biofeedback Improves Upper Extremity Function in Children with Cerebral Palsy. Retrieved September 3, 2010 from

Biofeedback of muscle activity is commonly used as an adjunct to physical therapy, but it has not previously been used for long-term treatment of movement disorders. The authors hypothesized that chronic daily use of biofeedback of muscle electrical activity might promote improved use of the upper extremity in children with cerebral palsy and upper extremity motor deficits. They constructed portable electromyography (EMG) unit that includes a surface EMG sensor and amplifier, microcontroller-based nonlinear signal processing, and vibration feedback of muscle activity.

A total of 11 children ages six to 16 years, with cerebral palsy or acquired static brain injury, wore the device at least five hours per day for one month. Changes in upper extremity function were assessed using an individualized Goal Attainment Scale. Results showed significant clinical improvement in all 10 children who completed the study. These results suggest that further testing of prolonged surface EMG biofeedback is warranted.
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