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Sponsor: Institute of Spinal Cord Injury, Iceland




1) Introduction

2) How It Works

3) Biofeedback for SCI

4) Questions and Answers

5) Conclusion

6) Availability


Introduction: Biofeedback is a subtle training technique used to enhance mind-body control. By providing subjects with external audio or visual feedback of subtle nervous signals that reach the muscles, using electrodes to sense the signals, biofeedback provides a means for identifying, strengthening, and using these signals. Through this technology, biofeedback lets subjects know when they are changing their physical responses – such as nerve signal strength, body temperature, blood pressure, or heart rate – in desired directions. This information can be used to teach individuals to better control their body.

Under certain conditions, biofeedback can assist individuals with SCI to regain or improve functional usage of motor nerve cells in the brain, brain stem, and spinal cord, which can lead to improved use of disabled limbs.

Dr. Bernard Brucker, Founder of the Biofeedback Laboratory at the University of Miami’s School of Medicine, developed an internationally recognized biofeedback method that uses precise techniques to restore lost functions in those with neural impairment, called the Brucker Method. According to Brucker, his aim in developing his method was to improve the lives of those with neurological motor impairment by providing a bridge between neuroscience and rehabilitation.

Biofeedback was initially viewed with skepticism by traditional medicine. However, repeated studies confirmed that individuals could change both voluntary and involuntary responses after being fed back information that revealed what was occurring in their bodies. After treatments, patients retain the ability to repeat learned responses at will, without visual or audio feedback.

In 1969, the use of audio-visual information to train subjects to alter blood pressure, heart rate, muscle tension, and brain activity was first termed “biofeedback.” O. Hobart Mowrer pioneered the use of instruments to control bodily functions in 1939, using alarms triggered by urine to stop children from bedwetting. Biofeedback first gained the public’s attention in the late sixties, when it was used to demonstrate the biophysical self-control of yogis in altered mental states.

 Biofeedback has been used to treat migraine headaches, tension headaches, chronic pain, digestive-system disorders, urinary incontinence, high blood pressure, cardiac arrhythmias, attention deficit hyperactive disorder, Raynaud’s disease, epilepsy, SCI, stroke, traumatic brain injury, cerebral palsy, and various movement disorders.

How Biofeedback Works 

“A reinforcing stimulus is roughly the same as a reward. If a person does something and receives a ‘reinforcer,’ he will probably do the same thing again the next chance he gets.” —Richard Malott, (1972)

Biofeedback is a form of operant learning; psychologist Leland Swenson says of EMG biofeedback as an operant training technique:

EMG biofeedback has been extended into the medical areas of deficient neuromuscular control. Inglis, Campbell, and Donald (1976) reviewed applications of EMG biofeedback in treating peripheral nerve muscle damage, the effects of strokes, partial paralyses, and cerebral palsy (early brain damage having a motor component). They cite considerable evidence to suggest that patients can learn to gain more control over the involuntary activity of voluntary muscles. This neuromuscular reeducation approach has been successful in restoring function to paralyzed limbs where some neural control remains. Within a couple of hours, those patients who had at least a few intact nerve endings were producing sufficient motor unit action potentials from these surviving nerve endings to achieve large percentages of normal, voluntary muscle functioning. The various studies reported 50% to over 85% of patients benefited from such treatments. [Applications of Operant-Related Learning Principles to the Real World, Leland Swenson] 

For SCI applications, the Brucker method of biofeedback operant training uses electromyography (EMG), which senses motor action potentials (nerve “impulses” or signals) with far greater precision and sensitivity than the user can. Electromyography therapy determines the bioelectrical function of a patient's muscles, which indirectly reveals the functional condition of the spinal cord and brain.

During biofeedback treatment, the patient is requested to perform intended movements. Using a movable graph on a computer screen, EMG provides visual feedback of neural signals that reach the target muscles. The subject may need repeated attempts to “find” a neural pathway that delivers a signal to target muscles. But even then the signal is often too weak for the subject to sense.

Once a neural path is found, the therapist directs the subject to make the EMG graph “grow.” This can only occur by increasing the strength of the motor signal that reaches the muscle. However, because the subject may not sense the signal, or signal variations may be too slight to be felt at first, the moving chart provides the reinforced stimulus necessary for operant learning to occur.

Thus, visual feedback teaches the subject how to reproduce, maintain, and control EMG responses for maximum improvement in muscle function. This information, combined with behavioral conditioning techniques and rehabilitation, helps subjects reeducate their muscles. The level of control gained in one session is the starting point for the next.

Biofeedback for SCI: For SCI, the Brucker Biofeedback Technique uses the Neuroeducator 3 Electromyography (EMG) Biofeedback System, which allows therapists to identity subtle motor connections between the brain and the body that survive SCI, or that have slowly repaired or rebuilt since being damaged. This information allows therapists to design individually customized plans aimed at restoring or improving voluntary muscle control.

The Brucker technique is the only biofeedback protocol specifically designed to enhance neural conduction and functions in subjects with neurological injury and disease. Unlike general uses of biofeedback to enhance relaxation, or to control blood pressure or heart rate, biofeedback for SCI requires equipment sensitive enough to monitor neural signals to within one percent of a normal signal. In addition, for SCI applications biofeedback-trained therapists should know which muscles are needed to regain specific motor functions, the signal strength needed for specific muscles to function, and techniques for helping the subject find and develop these signals.

People with SCI have regained much lost motor function after biofeedback training. The results sometimes appear as miraculous. People who were told that they would never walk or use their hands have regained the ability to walk or feed themselves. Restored functions become natural through practical use. However, motor improvements through biofeedback training require specific physical conditions:

1.     A neural connection must exist between the brain and the muscle (or muscle group) that is desired to move. Such connections might have survived initial SCI, or they may have repaired over time, or they may be the spinal cord’s attempt to rewire itself through existing connections.

2.     The patient must be aware and able to mentally respond to therapist directions.

3.     Muscular atrophy or contractures cannot be so severe that they’re unable to be corrected. Electrical stimulation therapy may be needed to strengthen or rebuild atrophied tissues, allowing them to fully benefit from biofeedback. Because physiatrists can be reluctant to prescribe such therapy to retard or reverse atrophy when no obvious muscle contractions are present, biofeedback evidence of an existing signal can be used to show a need.

4.     Biofeedback can be used to monitor any neural signal provided that an external electrode can be positioned to sense and relay the signal to an external device that’s able to represent the signal’s presence and strength. Although biofeedback can be used to improve functions in the hands or feet, muscles in fingers or toes can be too small for electrodes to fit.

Understanding biofeedback potentials and limitations reveals the importance of maintaining muscle tone, flexibility, and bone density through personal care. The above requirements are needed not only in using biofeedback to train the body in using existing, but disused neural connections, but will also be needed for individuals with SCI to benefit from emerging treatments that repair or regenerate the spinal cord.

Sources of neural connections through the spinal cord after SCI include, for example, existing pathways, alternate pathways, damaged pathways that spontaneously repair over time, pathways that spontaneously rewire over time, and surgically reconstructed pathways

According to Brucker, it is extremely rare that all of the cord’s neural connections are lost due to SCI. A “complete” classification of SCI (compared to an “incomplete” injury) is a functional description of neurological symptoms, rather than a physical description of the spinal cord itself. Nerve connections between the brain and muscles below the level of injury often survive SCI, but signals over these connections are too weak to be felt in a neurological examination or to move affected limbs.

In addition to Brucker’s observations of biofeedback’s clinical use, studies involving Transcranial Magnetic Stimulation provide supporting evidence. Dr. G.A. Delaney and colleagues (London, Canada) found that axons could survive through the injury site in patients with “longstanding” SCI, preserving "axonal integrity in descending motor tracts in the face of extensive functional loss."

Similar to the brain, redundancy is believed to be part of the spinal cord’s design. Several neural pathways may connect the brain to specific targets in the body, rather than one. But a lifetime of repeated use conditions our brains to see certain pathways as the connection for certain uses. Brucker makes the analogy of a favorite route between the workplace and home. If construction closes the road, we still go home – provided we find and learn to use an alternate route.

Over time, repairs may naturally occur to demyelinated axons, or broken axons may find and remake lost connections in the injured spinal cord. Axon regrowth is limited by the extent of gliosis (the formation of the “glial scar” that occurs during acute SCI) and the presence of inhibitory molecules in the spinal cord’s extracellular matrix, which were released due to damage to myelin sheathing.

Finally, medicine is beginning to test methods for repairing or regenerating the damaged spinal cord. The brain may find it difficult to find and use newly created neural connections, or repaired connections that have been chronically “turned off.” For all these potentials, biofeedback provides a means for finding, improving, and using these connections.

Biofeedback for SCI: Questions & Answers

1) How does biofeedback work? Biofeedback is not a treatment in the sense that something is done to the subject. Similar to learning to ride a bicycle, biofeedback teaches users to sense and make use of potential abilities through experience. For example, it’s impossible to explain the balance needed to ride a bicycle to someone else. They need to feel it for themselves – but once felt and controlled they retain the skill for life.

In practice, biofeedback for SCI uses external electrodes to sense subtle neural signals that reach the muscles when the subject tries to move them. The electrodes relay this information to a device that’s able to represent the signal and its strength visually, or with sound. The Brucker approach usually presents a line graph that changes with increasing signal strength.

Subjects are directed to contract the monitored muscle. The EMG system is able to sense and reveal slight neural signals that the subject may not feel. Once a signal is found, the subject is instructed to try to focus not on the arm or leg, but on the graph, while they attempt to make the graph grow. If sounds are used, they’re instructed to turn the sound on or off. For example, when attempting to decrease spasticity a subject may be directed to turn a sound off, which would correspond to controlling the unwanted ‘spasticity’ signal. When directed to increase a motor signal the subject would try to turn the sound on.

With trial and error and repetition, subjects may find more effective pathways for producing desired results. Once these pathways are found and used, the brain remembers where they are and how to use them. Improvements gained in one biofeedback session are the starting point for the next.

2) How soon will the therapist know if improvements are possible? A biofeedback-trained therapist can tell during the first treatment whether neural connections exist for each muscle tested. The likelihood of functional improvements depends on the strength of motor signals that reach the muscles. For example, the quadriceps requires roughly 14% of a normal motor signal to trigger voluntary contractions. If 10% percent of a normal signal reaches the muscle when the subject attempts to move it, prior experience suggests that the movement threshold might be reached in the first or second biofeedback session. More sessions are needed if the initial signal is lower, but still strong enough to suggest that a muscle’s functional threshold might be reached. If no signal can be found, or if no improvement can be made on trace signals, it is unlikely that the muscle’s functional threshold will be reached at that time. A clinical study involving one hundred subjects with upper extremity SCI reported the following:

“A significant increase in EMG activity occurred from the triceps after one biofeedback treatment session and further significant increases in EMG activity occurred after additional biofeedback treatment sessions. Initial muscle strength and initial EMG levels were not determining factors for response to the biofeedback. The results suggest the efficacy of biofeedback for increasing voluntary EMG responses in long term spinal cord injury patients.”

3) Does injury level or neurological “completeness” limit potential benefits? Biofeedback therapy can lead to functional improvements in subjects with SCI regardless of level of injury or completeness. Moreover, MRIs are unable to accurately predict outcomes of biofeedback treatments, because they are unable to determine the neural conductivity. Subjects with injuries evaluated as “complete” have made substantial improvements through biofeedback. Whereas others with slight to moderate incomplete SCI have improved only slightly. According to Brucker, it is rare that biofeedback therapy fails to exert some degree of positive effects.

4) Does time post injury affect possible effects? Biofeedback treatment outcomes for those with SCI can be affected by time post injury for the good or bad. Patients who had little neural sparing through the injury site soon after injury can have considerable disused connections ready to be found and used, once enough time elapses to permit neural repair, or remodeling. On the down side, too much time post injury contributes to muscle atrophy, contractures, and loss of bone density; these can all adversely affect an individual’s ability to benefit from biofeedback. For example, if a tendon becomes to too contracted, it may be unable to respond to biofeedback-identified and -strengthened signals.  

5) What degree of improvement is typically seen in patients with SCI? Brucker estimates that 98% of individuals with SCI who undergo his method improve at least one vertebra level of functionality; therefore the condition of an individual with cervical C7 SCI might improve to that generally found in those with thoracic T1 injury. Nine-five percent of his patients improve two vertebra functional levels, and 85% improve three. Improvements greater than this are too erratic to predict. However, biofeedback improvements may occur in functions controlled by nerves that leave the cord far below the subject’s lesion, before being seen in functions controlled by nerves that exit the cord just below the injury site.  

Depending on which muscles can be fired through biofeedback and strengthened through rehabilitation, it may be possible for previously wheelchair-using individuals to stand and ambulate. Specific muscles (quadriceps) are needed to stand, and others (hip flexors) are needed to walk. However, the use of braces or adjusted patterns of gait might allow a subject to stand or ambulate – even if control of the quadriceps and hip flexors is not achieved. This also applies to the muscles of the calves, feet, and ankles, or to the upper extremities. In other words, a BFB-trained therapist will try to improve as many functions as possible. But if some motor functions do improve, while others do not, improvements in limb function might still be gained. 

6) How long does a typical session last for a subject with SCI? One hour.

7) Has biofeedback led to positive effects in SCI patients for urinary, bowel, respiratory, spasticity/clonus, or pain issues? Biofeedback can produce positive effects on urinary incontinence, bowel control, respiration, spasticity, and clonus. It is ineffective for treating SCI-related chronic pain. Improved muscle tone and control of abdominal muscles can indirectly improve bowel and bladder control. Spasticity and clonus often decrease when improvements are made in voluntary motor signal strength. Previously ventilator-dependant subjects have improved the use of intercostal muscles, which assists breathing with the upper chest cavity (as opposed to diaphragmatic breathing), allowing these individuals to become ventilator independent.   

8) How many sessions are usually required to achieve maximum results? Fifteen sessions are normally advised for a course of biofeedback treatment for SCI.

9) What physical factors determine the outcome of biofeedback treatments? To be effective, neural pathways must be exist between the brain and muscles that control desired functions. Neural signals over these connections may be weak or the connection may be dormant. But a pathway must exist for biofeedback to exert an effect. Target muscles must be able to respond to neural signals. Excessive atrophy and tendon contractures can prevent the use of limbs, regardless whether a neural connection is found or strengthened.  

10) Can Biofeedback reverse muscular atrophy? Muscle mass may be improved if biofeedback therapy leads to functional use. Moderate to severe atrophy may require the use of therapeutic electrical stimulation to rebuilt atrophied muscles along with biofeedback. However, an initial biofeedback evaluation can reveal if nerve signals are present in atrophied muscles that might lead to functional improvements once the muscles are rebuilt. 

11) Are additional rehabilitation regimens recommended for biofeedback subjects? Biofeedback is more effective when combined with other forms of rehabilitation. For reasons discussed before, it is recommended that individuals considering biofeedback attempt to maintain flexibility, bone density, and muscle mass. If biofeedback therapy succeeds in identifying and strengthening neural pathways, physical rehabilitation may optimize their functional use.

12) Are follow-up treatments indicated once improvements plateau? Once improvements plateau, further biofeedback therapy is unlikely to lead to additional gains. However, because neural repairs in the damaged spinal cord can slowly occur over time, periodic biofeedback evaluation may reveal new potentials for functional improvements.

13) Has biofeedback been used with other function-enhancing modalities or reparative/regenerative interventions? Biofeedback has been used successfully with therapeutic electrical stimulation to maintain or restore muscle mass and standard physical rehabilitation practices. Because biofeedback offers an effective means for finding new neural connections and training the patient in their functional use, it should synergistically enhance the potential benefits accruing from the many function-restoring therapies emerging throughout the world.

14) Is Biofeedback ineffective for any functions commonly lost or impaired through SCI? Biofeedback is ineffective for restoring sensation lost through SCI. Nor does it alleviate chronic pain due to spinal cord damage.

15) What contraindications exist for biofeedback? Because biofeedback therapy does not “do” anything to the body, few contraindications exist. However, because resulting functional improvements can require strenuous physical effort, individuals interested in biofeedback may need to be aerobically fit.

16) Where is the Brucker biofeedback method offered? The procedure is available in several locations in the U.S., Europe, the Middle East, Central America, South America, and Asia (see below). 

Conclusion: In conclusion, Brucker emphasizes: “Many individuals facing permanent functional losses due to central nervous system (CNS) damage have neurological potential for greater functional recovery, even long term post onset. Biofeedback techniques can be extremely powerful in gaining this increase in function through more efficient use of the CNS, but only if applied properly.”

In addition to improving the lives of individuals with SCI, Brucker believes that biofeedback offers a valuable means for maximizing functional gains from neural repairs – whether they occur naturally, or result from clinical treatments. He notes: “Recent findings in neurological and behavioral sciences have shown that CNS cells, if damaged, have potential for remyelination and axonal repair which can take place years post damage from injury or disease. It is also now known that the CNS can have both dendrite and axonal sprouting in its attempt to regain integrity. While the functional correlates of such neural repair were once thought to be automatic, it is becoming clear that to maximize this neural potential, specific learning techniques at the neuronal level are necessary. Advanced biofeedback is the technique best suited for maximizing this potential.”


Main Center

bulletBrucker Biofeedback Laboratory, University of Miami School of Medicine/MJHHA, 5200 NE 2nd Ave, Miami, FL 33137; (telephone: 305-762-3882; email: eroberts@mjhha.org.

Other U.S. Centers


Florida Hospital, 5165 Ananson St, Orlando, FL 32804 (407-303-7600).


Cora Rehabilitation Clinic, 527 E Long Ave, New Castle, PA 16101 (724-654-4545).


St. David's Rehabilitation Center, 1005 E 32nd St, Austin, TX 78705 (512-476-7111).


Mary Free Bed Rehabilitation Hospital, Wealthy SE, Grand Rapids, MI 49503 (616-242-0360).

International Centers


Neurological Education Center, Beijing Rehabilitation Center, Beijing Shijingshan District, Badachu Rd, Beijing, China (010-88961133, ext 2204).


Dr. Bernard Brucker Rehabilitation Center, Santa Anna University, Rua Voluntarrios da Patria #257, Santana, Sao Paulo, Brazil 02011 000 (5511 2175 8050).


Hospital de Nino, Apartado 4087, Zona 5, Panama, Republic of Panama (001 507 225 1583).


Jerusalem Community Health Center, 30 Tachkemoni St, PO Box 6851, Jerusalem, Israel (011 972 25381820).


Orthopadische Klinik Munchen-Harlaching, Zentrum fur Kinderorthopadie, Leitender Arzt Dr. med. Peter Bernius, Harlachinger Strasse 51, 81547 Muchen, Germany (0 89 62 11 20 71).


Mallya Hospital, No 2, Vittal Mallya Rd, Bangalore, India 560 001 (91 80 2277979).


German scientist Ulrich Schmidt developed IMF® therapy, which is being used in a number of clinics (e.g., www.imf-therapy.co.uk) to treat a variety of neurological disorders, including SCI. Like other biofeedback therapies, IMF is based on the scientifically proven fact that in most spinal-cord injuries, even those clinically classified as complete, some intact, albeit perhaps dormant, neurons still transverse the injury site. Through appropriate rehabilitative programs and building upon inherent plasticity (i.e., adaptability) of the nervous system, these surviving neurons lay the foundation for new function-restoring neuronal networks, pathways, and connections.

With IMF, residual nerve signals generated by the mental intention to move muscles below the injury site are recorded at those muscles. The IMF device amplifies these faint impulses and then sends the amplified signals back to the target muscles. With practice, this process builds up nascent function-restoring networks and, in turn, voluntary muscle movement and strength. Unlike passive FES muscle stimulation, the patient’s intention is the driving force behind restored function.

At the 6th European Trauma Congress (May 2004), Schmidt and colleagues presented the results of a study evaluating the effects of IMF therapy in subjects with paraplegia:

“19 paraplegic patients ranging from 1 month to 43 years after spinal cord damage performed IMF-therapy with the aim of achieving better stability in their body. After one month 18 patients had better proprioceptive feedback and one patient had no change. After two months 11 patients (60%) were able to intensify voluntary muscle activity. After three months 3 patients (15%) were able to stand and walk on crutches or with a metal walker – one of them 43 years after spinal cord damage.”