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Upon first seeing their MRIs, many people with spinal-cord injury (SCI) have said to themselves, "But everything below my injury can't be paralyzed! There's barely a notch in my spinal cord!"

Perhaps SCI’s cruelest aspect is its uncertainty. We wonder how our bodies could become so impaired through so little apparent damage, whether its lost functions might one day return, and what types of repairs are needed to regain them.

Since the 1970s, a passive neuromuscular training technique developed by Dr. Bernard Brucker, University of Miami, called the Brucker Biofeedback Method, has allowed many with SCI to regain functional abilities. 

This method uses visual “feedback” from an electromyography (EMG) device. Through sensitive electrodes placed over muscles, EMGs sense motor-action potentials (nerve “impulses” or signals) with great precision. The EMG visual display allows users and therapists to “see” subtle neural signals that reach the muscles from the brain, which the user is unable to sense. Seeing these signals enables trained therapists to choose specific rehabilitative techniques aimed at strengthening the signals until they produce a desired functional effect, e.g., the user can voluntarily contract a previously paralyzed muscle.

This technique has improved the quality of life for many with SCI by shedding light on one of its previously uncertain aspects: the cord's functional potential in its chronically injured state. However, as reparative treatments for chronic SCI move from the lab to the clinic, biofeedback’s benefits to the paralyzed community may broaden far beyond its present uses; they may be integral to emerging regenerative successes.

This two-part article explores biofeedback’s proven benefits and future potentials. 

How Biofeedback “Works”

Biofeedback is a form of operant learning, which uses a “reinforced stimulus” as a reward to encourage the subject to repeat a desired action. During biofeedback, the patient is requested to perform intended movements. Using a movable graph on a computer screen, the EMG provides visual feedback of neural signals that reach target muscles. The subject may need repeated attempts to “find” a neural pathway that delivers a signal. But even then the signal is often too weak for the subject to sense.

Once a pathway 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, EMG feedback is used to provide the “reinforced stimulus” necessary for operant learning to occur.

By teaching subjects how to reproduce, maintain and control EMG responses for maximum improvements in muscle function, EMG visual feedback – combined with behavioral conditioning techniques and rehabilitation – helps subjects “re-educate” their muscles. The control gained in one session is the starting point for the next.

SCI Applications

The Brucker Technique uses the Neuroeducator 3 EMG Biofeedback System, which allows therapists to identity subtle motor connections between the brain and the body that survived injury, or that have slowly repaired or rebuilt since being damaged.

Unlike biofeedback to enhance relaxation, control blood pressure, or control heart rate, SCI biofeedback requires equipment sensitive enough to monitor neural signals to within 1% of normal signal. In addition, 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.

Subjects with SCI have regained many lost motor functions 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. However, motor improvements through biofeedback therapy require the patient to have specific physical conditions.



·        A neural connection must exist between the brain and target muscles. Such connections might have survived initial SCI, or they may have repaired over time, they may be the cord’s attempt to rewire itself through remaining connections, or they may result from regenerative treatments.

·        The patient must be able to mentally respond to therapists’ directions.

·        Muscular atrophy or contractures cannot be so severe that they’re unable to be corrected. Electrical stimulation may be needed to strengthen or rebuild atrophied tissues, allowing them to fully benefit from biofeedback. Because physiatrists can be reluctant to prescribe e-stem 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 for e-stem.

·        Target muscles must be large enough to support an electrode’s placement. 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.


Q & A

Dr. Bernard Brucker, founder and an original co-director of the Miami Project to Cure Paralysis, currently directs the University of Miami School of Medicine’s Biofeedback Laboratory. 

JPK: How soon can the therapist know if improvements are possible?

Dr. Brucker: A biofeedback 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 require roughly 14% normal motor signal to trigger voluntary contractions. If 10% reaches the muscle when the subject first attempts to move it, experience suggests that the movement threshold might be reached in the first or second session. More sessions are needed if the initial signal is lower, but still strong enough to imply that a muscle’s functional threshold might be reached.

JPK: Does injury level or neurological “completeness” limit potential benefits?

Dr. B: Biofeedback therapy can lead to functional improvements regardless of injury level or completeness. Moreover, MRIs are unable to accurately predict biofeedback outcomes, because they are unable to determine 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. It is rare that biofeedback fails to exert some benefits.

JPK: Does time post injury affect biofeedback’s possible effects?

Dr. B: Efficacy 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 might have considerable disused connections ready to be found and used, once enough time elapses to permit neural repairs, or remodeling. However, too much time post injury can contribute to muscle atrophy, contractures, and bone-density loss, which all adversely affect an individual’s ability to benefit from biofeedback.

JPK: How much improvement is typically seen?

Dr. B: Roughly 98% of individuals with SCI who undergo biofeedback improve at least one vertebra level of functionality. Therefore the condition of an individual with C-7 injury might improve to that generally found in those with T-1 injuries. Ninety-five percent improve two functional levels, and 85% improve three. Greater improvements are too erratic to predict. However, improvements may occur in functions controlled by nerves that leave the cord far below the lesion before being seen in functions controlled by nerves that leave the cord just below the injury site.

JPK: Can biofeedback lead to other benefits?

Dr. B: Biofeedback can have positive effects on urinary incontinence, bowel control, respiratory functions, and spasticity. It is ineffective for treating chronic pain. Improved muscle tone and control of abdominal muscles can indirectly improve bowel and bladder control. Spasticity often decreases when improvements are made in voluntary motor signal strength. Previously ventilator-dependant subjects have improved the use of intercostal muscles, which assists upper-chest-cavity breathing (as opposed to diaphragmatic breathing).

JPK: How many sessions are needed to achieve maximum results?

Dr. B: Fifteen sessions are normally advised.

JPK: Are follow-up treatments indicated once improvements plateau?

Dr. B: At this point, further therapy is unlikely to lead to additional gains. However, because neural repairs in the cord can slowly occur over time, periodic biofeedback evaluation may reveal new potential for improvement.


Although the Brucker Biofeedback Method has improved the lives of many with SCI, its contributions may only be barely tapped. Part two discusses intriguing potentials that biofeedback may yet have to offer.  

Adapted from article appearing in June 2007 Paraplegia News (For subscriptions, call 602-224-0500) or go to .