CI Therapy: A New Rehabilitation Technique for Aphasia and Motor Disability after Neurological Injury
CI Therapy: A New Rehabilitation Technique for Aphasia and Motor Disability after Neurological Injury
Edward Taub, Ph.D. Department of Psychology, University of Alabama at Birmingham, Birmingham
In this issue, F. Pulvermüller discusses some work involving the application of the approach to rehabilitation embodied in Constraint-Induced Movement therapy (CI therapy) to the treatment of aphasia after stroke that he carried out at the University of Konstanz in collaboration with B. Neininger, T. Elbert, B. Mohr, B. Rockstroh, P. Koebbel and myself.1 To fully appreciate the nature of this intervention it might be of value to understand both the context from which it emerged and the other treatments to which it is related. Patients with chronic stroke are a largely untreated group of individuals in the United States primarily because no therapy had been found that is successful in the rehabilitation of functionally meaningful movement in the life situation in this very large population.2 However, a new set of treatment techniques has been developed that data from controlled studies have indicated can substantially reduce the incapacitating motor deficit of the more-affected arm or leg of many patients with chronic stroke.3-6 The functional independence of these patients is thereby substantially increased. The treatment effect for the upper extremity has been replicated by my collaborators in Germany in the laboratories of W. H. R. Miltner,7 H. Flor,8 and T. Elbert.9 The procedures for this intervention are relatively simple, and it has been found to be almost uniformly effective for the approximately 75% of the chronic stroke population having significant residual motor deficit to whom it has been applied to date. CI therapy was derived directly from basic research with monkeys whose forelimbs had been surgically deprived of sensation.3,10 After deafferentation of one forelimb, monkeys do not use the affected extremity when unrestricted in the colony environment. However, they can be induced to use the deafferented limb by either of two general techniques: 1) restricting movement of the intact arm for 7 or more days, 2) training the deafferented arm. A useless limb is thereby converted into a limb that can be used extensively. Experiments indicated that the nonuse of an arm after deafferentation is a learning phenomenon, designated learned nonuse.3,4,6 It involves a learned suppression of movement and develops in the acute and early subacute periods. The reason that the techniques noted above are effective is because they overcome this learned nonuse. The same techniques are effective for producing a substantial rehabilitation of movement after stroke in humans. CI therapy consists of a family of treatments; their common element is that they induce stroke patients to greatly increase the use of a more-affected upper extremity for many hours a day over a period of 2 or 3 consecutive weeks (depending on the severity of the initial impairment). This concentration (or massing) of practice provides an effective bridge enabling the gains in motor ability produced by therapy in the laboratory to be transferred to the home so that there is consistent use of the more-affected arm there. This provides a remedy for the problem of lack of transfer of therapeutic gains obtained in the clinic to the real world environment, which has been a serious problem with other types of neurorehabilitative techniques. The signature intervention for the arm involves motor restriction of the upper extremity less affected by a stroke in a protective safety mitt or sling for a target of 90% of waking hours over a period of two or three weeks, while at the same time intensively training the arm affected by the stroke. Studies indicate that the intensive training is by far the more important component of the treatment package, producing at least 80% of the therapeutic outcome. The therapies result in large changes in amount of use of the more-affected arm in the activities of daily living outside the clinic that persist for at least the two years measured to date. As noted, they are thought to work because they overcome a learned nonuse of the more-affected arm that develops in the early post-stroke period as in the case of monkeys after deafferentation. Work has been carried out to date with close to 200 patients in this laboratory and its associated clinic and over 100 patients in other laboratories, with significant improvement in virtually every case. In four recent papers, my German collaborators and I have shown that CI therapy changes the organization and function of the brain so that large new areas of the nervous system are recruited into the generation of the movements of patients with stroke.11-14 The mechanism involved in this change is termed “use-dependent” cortical reorganization, discovered in monkeys in the laboratory of Dr. Michael Merzenich15-18 and subsequently demonstrated in humans at the University of Konstanz in the laboratory of Prof. Thomas Elbert.19,20 The fact that CI therapy produces a “massive” cortical reorganization has served to increase the credibility of the clinical results obtained with CI therapy. Dr. Randolf Nudo had previously demonstrated a similar phenomenon in monkeys with a technique very much like CI therapy.21 Our work represents a demonstration that an effective stroke rehabilitation therapy can serve to “rewire the brain” in humans. During the past four years the upper extremity intervention has been successfully extended to patients with traumatic brain injury.6 In addition, a lower extremity treatment deriving from upper extremity CI therapy has been developed that involves only intensive training of gait for the laboratory-standard 6 hours on each weekday over a period of 3 consecutive weeks. No physical constraint is placed on the less-affected leg. This intervention has been applied first to 42 patients with chronic stroke and then with equally good results to patients with spinal cord injury and patients with fractured hip who suffer from residual motor deficit after replacement or repair of the joint. A related therapy has also been developed for improving focal hand dystonia in musicians by Victor Candia in collaboration with Dr. T. Elbert and myself.22 The massed practice principle derived from CI therapy has also been found to be effective for the reduction of phantom limb pain after upper extremity amputation by Dr. T. Weiss in collaboration with Dr. W. Miltner and myself at the Friedrich Schiller University in Jena.23 The CI Aphasia therapy described elsewhere in this issue makes use of a basic technique pioneered by Dr. Pulvermüller24 and also the fundamental procedures employed previously in CI Motor therapy. Treatment is massed and carried out for many hours a day over consecutive weeks. The constraint is not physical as when it is produced by means of a device in the case of treatment of the upper extremity, but it is real nonetheless, being imposed by the rules of the “language game” that is the main part of each patient’s therapeutic regimen. Either the patients improve their linguistic ability or they lose the game they are playing. Exactly the same principle of success or reward made contingent on improved performance is embodied in the “shaping” procedure25,26 used in CI Motor therapy. Moreover, in CI Movement therapy for the lower extremity there is no physical restraint used, just as is the case for CI Aphasia therapy. A deficit in linguistic ability might not intuitively seem remediable by a treatment governed by the same therapeutic principles as are applied to a motor deficit of the extremities. However, both speech and movement are effector functions, though controlled by different parts of the brain. Therefore, it is perhaps not surprising that the same treatment principles are applicable to both. A clear implication of this line of reasoning is that after successful treatment with CI Aphasia therapy, the brain should show substantial plastic changes in the areas related to speech, as has been demonstrated to occur as a result of CI Motor therapy in areas relevant to extremity movement. What is surprising, however, is that CI Aphasia therapy had a beneficial effect not only on motor speech, but on linguistic comprehension as well, a nonmotor function. This is a potentially significant observation and suggests the value of exploring the usefulness of a CI therapy approach with other nonmotor deficits after neurological damage. Recent discoveries about how the central nervous system responds to injury through cortical reorganization and how to retrain or remediate impaired behavior have given rise to the development of several effective new therapies for the rehabilitation of function after neurological injury. Until now, neurorehabilitation has been largely static; few, if any of the older treatments have received evidence-based demonstrations of efficacy.2 However, a current melding of basic research in neuroscience and behavioral science gives promise of entirely new approaches to improving the behavioral, perceptual and cognitive capabilities of individuals who have sustained substantial neurological damage.27 The current state of change in the field of rehabilitation amounts to an impending paradigm shift. The application of CI therapy to the treatment of aphasia appears to represent one example of this new approach.
References 1. Pulvermüller F, Neininger B, Elbert T etal. Constraint-Induced therapy of chronic aphasia after stroke. Stroke 2001; 32: 1621-1626 2. Duncan PW. Synthesis of intervention trials to improve motor recovery following stroke. Top Stroke Rehabil 1997; 3: 1-20 3. Taub E. Somatosensory deafferentation research with monkeys: implications for rehabilitation medicine. In: Behavioral psychology in rehabilitation medicine: clinical applications. Ed. Ince LP. pp. 371-401. Williams Wilkins, New York, 1980 4. Taub E, Miller NE, Novack TA et al. Technique to improve chronic motor deficit after stroke. Arch Phys Med Rehabil 1993; 74: 347-354 5. Taub E, Crago JE, Uswatte G. Constraint-Induced Movement therapy: a new approach to treatment in physical rehabilitation. Rehab Psychol 1998; 43:152-170 6. Taub E, Uswatte G, Pidikiti R. Constraint-Induced Movement therapy: a new family of techniques with broad application to physical rehabilitation - a clinical review. J Rehab Res Devel 1999; 36: 237-251 7. Miltner WHR, Bauder H, Sommer M, Dettmers C, Taub E. Effects of Constraint-Induced Movement therapy on chronic stroke patients: a replication. Stroke 1999; 30: 586-592 8. Kunkel A, Kopp B, Muller G et al. Constraint-Induced Movement therapy: A powerful new technique to induce motor recovery in chronic stroke patients. Arch Phys Med Rehabil 1999; 80: 624-628 9. Sterr A, Elbert T, Berthold I, Kölbel S, Rockstroh B, Taub E. CI therapy in chronic hemiparesis: the more the better? Manuscript submitted for publication 10. Taub E. Movement in nonhuman primates deprived of somatosensory feedback. In: Exercise and Sports Sciences Reviews (vol. 4). pp. 335-374. Journal Publishing Affiliates, Santa Barbara, 1977 11. Liepert J, Bauder H, Sommer M et al. Motor cortex plasticity using Constraint-Induced Movement Therapy in chronic stroke patients. Neurosci Lett 1998; 250: 5-8 12. Liepert J, Bauder H, Miltner WHR, Taub E, Weiller C. Treatment-induced massive cortical reorganization after stroke in humans. Stroke 2000; 31: 1210-1216 13. Kopp B, Kunkel A, Mühlnickel W, Villringer K, Taub E, Flor H. Plasticity in the motor system correlated with therapy-induced improvement of movement in human stroke patients. NeuroReport 1999; 10: 807-810 14. Bauder H, Sommer M, Taub E, Miltner WHR. Effect of CI therapy on movement-related brain potentials. Psychophysiol 1999; 36: Suppl. 1, S31 (Abstract) 15. Jenkins WM, Merzenich MM, Ochs MT, Allard T, Guic-Robles E. Functional reorganization of primary somatosensory cortex in adult owl monkeys after behaviorally controlled tactile stimulation. J Neurophysiol 1990; 63: 82-104 16. Recanzone GH, Jenkins WM, Merzenich MM. Progressive improvement in discriminative abilities in adult owl monkeys performing a tactile frequency discrimination task. J Neurophysiol 1992; 67: 1015-30 17. Recanzone GH, Merzenich MM, Jenkins WM. Frequency discrimination training engaging a restricted skin surface results in an emergence of a cutaneous response zone in cortical area 3a. J Neurophysiol 1992; 67: 1057-70 18. Recanzone GH, Merzenich MM, Jenkins WM, Grajski A, Dinse HR. Topographic reorganization of the hand representation in area 3b of owl monkeys trained in a frequency discrimination task. J Neurophysiol 1992; 67: 1031-56 19. Elbert T, Pantev C, Wienbruch C, Rockstroh B, Taub E. Increased use of the left hand in string players associated with increased cortical representation of the fingers. Science 1995; 220: 21-3 20. Sterr A, Mueller MM, Elbert T, Rockstroh B, Pantev C, Taub E. Changed perceptions in Braille readers. Nature 1998; 391: 134-5 21. Nudo RJ, Wise BM, SiFuentes F, Milliken GW. Neural substrates for the effects of rehabilitative training on motor recovery following ischemic infarct. Science 1996; 272: 1791-4 22. Candia V, Elbert T, Altenmüller E, Rau H, Schäfer T, Taub E. Constraint-Induced Movement therapy for focal hand dystonia in musicians. Lancet 1999; 353: 42 23. Weiss T, Miltner WHR, Adler T, Bruckner L, Taub E. Decrease in phantom limb pain associated with prosthesis-induced increased use of an amputation stump in humans. Neurosci Lett 1999; 272: 131-134 24. Pulvermüller F, Roth VM. Communicative aphasia treatment as a further development of PACE therapy. Aphasiology 1991; 5: 39-50 25. Taub E, Burgio L, Miller NE et al. An operant approach to overcoming learned nonuse after CNS damage in monkeys and man: the role of shaping. J Exp Anal Beh 1994; 61: 281-293 26. Skinner BF. The technology of teaching. Appleton-Century-Crofts, New York, 1968. 27. Conference on “The impending paradigm shift in neurorehabilitation and remediation: the melding of basic research in neuroscience and behavioral science to produce advances in therapeutics.” University of Alabama at Birmingham, July 2001. Organized by Taub E, Elbert T, Miltner MHR