Edward Taub, PhD
Physical Medicine and Rehabilitation Service,
Birmingham Veterans Affairs Medical Center,
Birmingham, AL 35233 and Psychology Department,
University of Alabama at Birmingham, Birmingham AL 35294
A new discovery in physical rehabilitation is discussed in an article entitled "Constraint-Induced Movement Therapy: A new family of techniques with broad application to physical rehabilitation--A clinical review," which appears in this issue of the Journal. Constraint-Induced Movement Therapy (CI Therapy) techniques induce patients with cerebrovascular accident (CVA) and other types of injury to practice using an affected limb on an intensive or massed practice basis for consecutive weeks. The signature intervention for persons with CVA involves training use of the more-impaired arm in the clinic for at least 6 hours per day for from 10 to 15 consecutive weekdays and constraining use of the less-impaired arm both in the clinic and at home for the 2-3 week treatment period. Its most salient aspect is the demonstration in controlled studies that the treatment effect transfers to the real world where it substantially increases the actual amount of use of the more-impaired arm in activities of daily living.
The common therapeutic factor among the different CI Therapy techniques is massed practice. We have found that even when conventional physical therapy techniques are administered in a concentrated manner for consecutive weeks patients obtain a large benefit. There is evidence from several recent studies that extended and concentrated practice produces a large use-dependent cortical reorganization that substantially increases the size of the motor cortical areas involved in the innervation of movement of the more-affected limb. This recruitment of additional areas of the cortex in the innervation of movement provides a central nervous system basis for why the massing of practice is a critically important variable for rehabilitation. Virtually all rehabilitation therapies are currently administered on a highly distributed or spaced basis. However, the evidence from this laboratory and others suggests that rehabilitation treatments for many patients are most effective when they are administered on a concentrated or massed practice basis.
Consequently, it is important to consider changing the paradigm for the delivery of rehabilitation services. It is not so much the nature of the techniques that require revision (though we believe that CI Therapy research has uncovered some useful new approaches to the training of impaired limbs), but rather the intensity with which they are delivered. Changing conventional approaches to treatment will not be easy for a variety of practical and administrative reasons; however, the evidence available now could not be clearer on the value of administering rehabilitation treatments on a concentrated schedule.
The range of disorders for which CI Therapy might be an effective treatment encompasses a number of conditions in which motor disability is in apparent excess of the underlying organic pathology. Our research indicates that excess disability is an important component of many conditions in which there is motor impairment and which have been found to be refractory to current forms of treatment. As noted, the signature CI Therapy intervention is used for stroke patients with an upper limb paresis. The original therapy has recently been extended in this laboratory to successfully treat deficits in arm use in traumatic brain injury patients and to treat lower limb impairments in stroke, spinal cord injury, and hip fracture patients. A possible explanation for the excess motor disability in these patient populations is that it is being maintained by a learning phenomenon termed "learned nonuse." The present work stems from earlier basic research with monkeys (summarized in this issue of the Journal), which suggests that learned nonuse is established whenever 1) organic damage results in an initial inability to use a body part so that an individual is punished for attempts to use it and rewarded for using other parts of the body, and 2) there is recovery from, or healing of, the organic damage so that the person recovers the ability to use that body part, but the suppression of use learned in the acute phase remains in force. Thus, a portion of many motor deficits would appear to be due to the persistence of the original disability that initially had an organic basis. The nonuse is maintained after recovery from, or healing of, the organic injury by the operation of a powerful learned inhibition of movement that is normally permanent. However, it is potentially reversible and can be overcome by the application of an appropriate intervention, such as one of the several CI Therapy techniques.
The laboratories of Thomas Elbert, Ph.D. and Wolfgang Miltner, Ph.D., in collaboration with myself, have adopted the massed practice approach that characterizes CI Therapy to ameliorate focal hand dystonia in keyboard musicians and guitarists (T.E.) and have gathered evidence that supports concentrated use of a residual limb as a treatment for phantom limb pain (W.M). These new findings hold promise that a massed practice approach may yield effective new treatments for such refractory disorders as aphasia, and left-neglect after stroke and for chronic pain immobility syndrome. Another major issue that awaits resolution is determining methods that would be effective in preventing learned nonuse from supervening after injuries from which there is slow recovery, thereby preventing the development of dysfunctional states. Given the range of disorders for which CI Therapy has already shown itself to be an efficacious intervention, it seems possible that learned nonuse is a general mechanism that can be reduced or eliminated by a set of CI Therapy techniques that are fundamentally similar, though differing in details that are appropriate for the special needs imposed by different pathological conditions. This possibility warrants future investigation along a number of different avenues.
Edward Taub, PhD
This Guest Editorial is an invited opinion.
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Last Updated Tuesday, May 29, 2007 8:22 AM