Commentary. Constraint-Induced Movement Therapy: A New Approach to Treatment in Physical Rehabilitation

Transcription

1 Commentary Rehabilitation Psychology devotes a section of each issue to commentary on recent trends, concerns, or publications in rehabilitation psychology practice, research, and education. Articles appearing in this section may contain comments in reaction to specific pieces appearing in recent issues of the journal, and they may address methodological, theoretical, educational, or professional concerns. Manuscripts to be considered for this section should conform to the established editorial guidelines for the journal and not exceed 15 pages in length. Manuscripts should be submitted to the editor of the journal for processing, and authors should dearly indicate in a cover letter that the submission is for the Commentary section. The submission and subsequent correspondence will then be handled by the associate editor in charge of the section, TLrnothy R. Elliott, PhD, Department of Physical Medicine and Rehabilitation, University of Alabama, 1717 Sixth Avenue South, Birmingham, Alabama Ideas and suggestions for topics and authors are welcomed. Constraint-Induced Movement Therapy: A New Approach to Treatment in Physical Rehabilitation Edward Taub, Jean E. Crago, and Gitendra Uswatte University of Alabama at Birmingham ABSTRACT. Constraint-Induced (CI) Movement Therapy is a new approach to the rehabilitation of movement, based on research in neuroscience and behavioral psychology, that has been shown in controlled experiments to greatly increase the amount of use of an impaired upper extremity in chronic stroke patients in both the laboratory and the real world. CI Therapy consists of a family of techniques that induce stroke patients to greatly increase their use of an affected upper extremity for many hours a day over 10 to 14 consecutive days. The signature technique involves restricting the contralateral arm in a sling and training the affected arm. This commentary reviews the animal and human research and the theoretical formulation on which CI Therapy is based. 152 Rehabilitation Psychology, 1998, Vol. 43, No. 2, Copyright 1998 by the Educational Publishing Foundation, /

2 Constraint-Induced Movement Therapy 153 Traditional neurorehabilitation interventions have not been demonstrated to be effective in controlled studies. In a 1992 review of the stroke rehabilitation literature, de Pedro-Cuesta, Widen-Holmqvist, and Bach-y-Rim wrote that "as regards activities of daily life and motor function, differences between... rehabilitation in stroke units... and non-rehabilitation... were detected in relatively few quality studies and remained particularly inconclusive insofar as life in the home environment was concerned" (p. 433). In a 1997 review, Duncan reported that "clinical research studies to support the efficacy of the interventions are few" (p. 1). (See also reviews by Ernst, 1990, and Dobkin, 1989.) The weak contribution from such basic sciences as behavioral psychology and neuroscience to physical rehabilitation may account for the dearth of effective interventions. Neuroscience, in studying the nervous system and its pathology, focuses on the origin of dysfunction in neurorehabilitation patients. Operant conditioning, a branch of behavioral psychology, studies how to systematically modify behavior, which is the ultimate aim of physical therapy. These two disciplines should arguably have been the parent sciences of physical rehabilitation, but this has not been the case. Neuroscience holds an important place in the curriculum of physical therapy schools, but its influence has been largely didactic and has had little bearing on clinical practice. Behavioral psychology has contributed much to the treatment of chronic pain (e.g., Fordyce, 1991), but has had little or no place in the curriculum of physical therapy schools or in developing treatments for movement disorders. In other health-related fields, basic research has been of inestimable value in enabling the development of new therapeutic approaches. The limited practical influence of neuroscience on physical rehabilitation to date may well be because the findings, until recently, have been restricted to areas that are distant from obvious application to clinical practice. Recent discoveries about the processes of injury and central nervous system recovery, such as findings on nervous system damage in the early postinjury phase (reviewed in Novack, Dillon, & Jackson, 1996), spinal cord regeneration (reviewed in Schwab & Bartholdi, 1996), and cortical reorganization (Elbert, Pantev, Wienbrnch, Rockstroh, & Taub, 1995; Flor et al., 1995; Mezemich et al., 1984; Muehlnickel, Elbert, Taub, & Flor, in press; Pons et al., 1991; Taub, Flor, Knecht, & Elbert, 1995), have generated considerable interest. It is hoped that these findings will lead to new and effective rehabilitation interventions. Behavioral psychology has had little impact on the rehabilitation of movement, in part, because of the failure of biofeedback techniques to consistently effect changes in functional activity when applied to the treatment of movement disorders. In the 1960s, a strong interest developed in the application of operantconditioning techniques to the area of rehabilitation Once, 1969). Initial experiments involving the application of biofeedback procedures as a type of operant conditioning were promising; studies reported improvements in range of movement, manual muscle-test scores, and muscle tension as measured by electromyographic techniques (Wolf, 1983). Later work, however, failed to show that these physiological changes were persistent and related to changes in functional

3 154 Taub, Crago, and Uswatte activity, so that biofeedback techniques came to be viewed as having questionable clinical significance (Duncan, 1997; Wolf, 1983). The disappointment engendered by the biofeedback research appears to have spread to all operant-conditioning techniques. Consequently, there has been very little interest in the application of operant-conditioning techniques to the rehabilitation of movement in recent years. Movement science, the study of motor learning and the kinetics and kinematics of movement, has had a substantial influence on the practice of physical therapy. However, it has not led to the formulation of effective interventions, probably because early models of motor control, including reflex and motor hierarchy theories, gave incomplete accounts of human movement. These incomplete theories led to the facilitation approaches in physical therapy, which have proven to be ineffective (Duncan, 1997; Horak, 1992; Shumway-Cook & Woollacott, 1995). Current models of motor control, which include systems, dynamicalaction, task-oriented, and ecological theories, provide more comprehensive explanations of human movement than early models, but have yet to yield a large enough body of knowledge to provide specific implications for clinical practice. This problem is evident in the difficulty of operationalizing the task-oriented approach to physical therapy (Horak, 1992; Shumway-Cook & Woollacott, 1995). In addition, motor-learning research has been conducted largely with healthy rather than neurologically impaired participants, has focused on artificial tasks, and has used limited parameters of movement such as speed and error rate to index the full range of use of an extremity in activities of daily living. As the work herein described shows, findings based on such laboratory-based tasks and outcome variables may not be applicable to the most salient targets of physical therapy: functional activities in the home. Constraint-Induced (CI) Movement Therapy is a new approach to the rehabilitation of movement (Taub, 1980), based on research in behavioral psychology and neuroscience, that has been shown in controlled experiments to greatly increase the amount of use of an impaired upper extremity in chronic stroke patients in both the laboratory and the real world (Taub et al., 1993; Taub, Pidikiti, DeLuca, & Crago, 1996; Taub & Wolf, 1997; Wolf, Lecraw, Barton, & Jann, 1989). CI Therapy is made up of a family of treatments that involve focusing attention on and repeatedly practicing use of the stroke-affected arm in the clinic and, in most variants, constraining use of the unaffected arm both in the clinic and at home (Morris, Crago, DeLuca, Pidikiti, & Taub, 1997). These treatments emerged directly from basic research that used operant-conditioning techniques to change the arm-use behavior of monkeys from whose forelimbs somatic sensation had been surgically abolished (Taub, 1977). A major review of stroke-rehabilitation interventions singled out CI Therapy as "the most promising" evidence that motor recovery can be facilitated in stroke patients with some purposive movement of the hand and as one of the few treatment modalities for which there is sound evidence of transfer of therapeutic effect from the clinic to the life situation (Duncan, 1997). In this commentary, we review the animal research on which CI Therapy is

4 Constraint-Induced Movement Therapy 155 based, provide a model explaining its operation in terms of learning followed by use-dependent cortical reorganization, summarize the research on the application of CI Therapy to chronic upper extremity hemiparesis in stroke patients, and suggest future applications. We also discuss principles that have emerged during the course of this work that may enable the conversion of conventional physical therapy, biofeedback, and other techniques into effective treatment modalities for the long-term improvement of degraded motor patterns and functional activity. AN ANIMAL MODEL OF LEARNED NONUSE When a single forelimb is deafferented in a monkey, the animal does not make use of it in the life situation (Lassek, 1953; Mott & Sherrington, 1895). However, by restricting movement of the intact limb for several days, the monkey can be induced to use the deafferented extremity permanently. Training of deafferented limb use also proved to be an effective technique. Initially, conditioned-response techniques were used to train limb use (Knapp, Taub, & Berman, 1958, 1963; Taub, 1977; Taub, Bacon, & Berman, 1965; Taub, Ellman, & Berman, 1966; Taub, Williams, Barro, & Steiner, 1978). Subsequently, it was found that shaping techniques, which involve increasing behavioral requirements by very small steps (Morgan, 1974; Panyan, 1980; Skinner, 1938, 1968), are considerably more effective (Taub, 1976, 1977). Several converging lines of evidence suggest that nonuse of a single deafferented limb is a learning phenomenon involving a conditioned suppression of movement (Taub, 1977, 1980). The restraint and shaping techniques appear to be effective because they overcome learned nonuse. Substantial neurological injury usually leads to a shock-like phenomenon, whether at the level of the spinal cord (spinal shock) or brain (diaschisis or cortical shock). Deafferentation initially results in a reduction within the spinal cord in the background level of excitation that keeps neurons ready to respond. This effect is most marked in the deafferented segments of the spinal cord, where the depressed condition of the motor neurons greatly elevates the threshold for excitation necessary to produce movement. With time, recovery processes raise the background level of excitability of motor neurons so that movements, at least potentially, can be expressed. In monkeys, the period of spinal shock lasts from 2 to 6 months following forelimb deafferentation (Taub, 1977). The inability of the monkeys to use the deafferented limb due to spinal shock leads to conditioned suppression of use of that limb. Animals with one deafferented limb try to use that extremity in the immediate postoperative situation, but they cannot. Attempts to use the deafferented limb often lead to painful and otherwise aversive consequences, such as falls and loss of food. These failures in use constitute punishments that suppress arm use (Kimble, 1961). Meanwhile, the monkeys get along quite well in the laboratory environment on three limbs and are therefore positively reinforced for this pattern of behavior, which as a result is strengthened. These contingencies of reinforcement lead to a persistence of the

5 156 Taub, Crago, and Uswatte nonuse of the affected extremity. Consequently, the monkeys never learn that, several months after the operation, it had become possible to make use of the limb. The restraint of the intact limb several months after unilateral deafferentation serves to overcome this conditioned suppression of movement or learned nonuse. Restriction of the intact limb induces animals to use the deafferented limb or forego feeding, locomotion, and other important dally activities with any degree of efficiency. This change in motivation overcomes the learned nonuse of the deafferented limb and consequently the animal uses it. J An experiment was carried out to test the learned-nonuse formulation directly (Taub, 1977, 1980). Movement of a unilaterally deafferented forelimb was prevented with a restraining device in several animals so that they could not attempt to use that extremity for a period of 3 months following surgery. The reasoning was that in preventing an animal from trying to use the deafferented limb during the period before the spinal shock had passed off, one should thereby prevent the animal from learning that the limb could not be used during that interval. In conformity with this prediction, the animals were able to use their deafferented extremity in the free situation after the restraint was removed. Suggestive evidence in support of the learned-nonuse formulation was also obtained during the course of deafferentation experiments carried out on the day of birth (Taub, Perrella, Miller, & Barro, 1973) and prenatally (Taub, 1980; Taub, Perrella, Miller, & Barro, 1975). USE-DEPENDENT CORTICAL REORGANIZATION Recent magnetic source imaging studies with humans, carried out by a group of investigators including one of the coauthors (ET), and an intracortical microstimulation (ICMS) study with monkeys suggest that cortical reorganization may be associated with the therapeutic effect of CI Therapy. The human imaging studies followed the seminal work of Merzenich and coworkers on use-dependent cortical reorganization in monkeys (e.g., Merzenich et al., 1984), and showed that the cortical somatosensory representation of the digits of the left hand was larger in string players, who use their left hand in the dexterity-demanding task of fingering the strings, than in nonmusician controls (Elbert et al., 1995). Moreover, the representation of the fingers of blind Braille readers, who use several fingers simultaneously to read, was found to be enlarged (Sterr et al., 1998). These results, in conjunction with research on cortical reorganization in adult phantomlimb patients (Flor et al., 1995), suggest that the size and nature of the cortical representation of a body part in adult humans depends on the amount of use of that part. The ICMS study demonstrated that in adult squirrel monkeys, who were surgically given an ischemic infarct in the cortical area controlling the movements of a hand, training of the affected limb results in cortical reorganization so that the area surrounding the infarct not normally involved in control of the hand comes to participate in that function (Nudo, Wise, SiFuentes, & Milliken, 1996). These

6 Constraint-Induced Movement Therapy 157 findings suggested the possibility that the increase in affected arm use produced by CI Therapy results in a use-dependent increase in the cortical representation of the affected arm, which provides the neural basis for a permanent increase in the use of that extremity. This hypothesis has recently been confirmed in a transcranial magnetic stimulation (TMS) study in which it was found that the cortical region from which electromyographic responses of a hand muscle can be elicited by TMS more than doubled after CI Therapy in chronic stroke patients compared with the pretreatment period (Liepert et al., in press). APPLICATION TO CHRONIC STROKE PATIENTS Development of CI Therapy Learned nonuse is hypothesized to develop in some humans after stroke by similar mechanisms to those that operate after deafferentation in monkeys, with the difference that the initial period of motor incapacitation would be due to cortical rather than spinal shock. It was therefore felt that the techniques that overcome learned nonuse in monkeys following unilateral deafferentation should also constitute a potential treatment to increase the amount of limb use in chronic stroke patients with upper extremity hemiparesis (Taub, 1980). Ince (1969) and Halberstam, Zaretsky, Brucker, & Gutman (1971) carried out the initial studies of the application of CI Therapy to humans. Ince transferred the conditioned-response techniques used with the deafferented monkeys directly to the rehabilitation of movement of the paretic upper extremity of 3 chronic stroke patients. He tied the unaffected upper extremity of the patients to the arm of a chair, while asking the patients to flex their affected arm to avoid an electric shock. The motor status of two of the patients did not change; the third patient, however, improved substantially in the training and life situation (Ince, 1969). Halberstam et al. used a similar treatment protocol with a sample of 20 elderly stroke patients and 20 age-matched controls. Treatment-group participants were asked to flex their affected arm to avoid the electric shock and, also, to make a lateral movement at the elbow to avoid shock; the unaffected arm was not tied down. Most of the patients in the treatment group increased the amplitude of their movements in the two conditioned-response tasks; some showed very large improvements (Halberstam, Zaretsky, Brucker, & Gutman, 1971). There was no report of whether this improvement transferred to the activities of daily life. Steven Wolf and coworkers (Ostendorf & Wolf, 1981; Wolf, Lecraw, Barton, & Jann, 1989) applied the unaffected-limb-constraint portion but not the affectedlimb-training component of Taub's (1980) treatment protocol to the rehabilitation of movement in chronic neurologically impaired patients with a upper extremity hemiparesis. The 1989 study included 25 stroke and traumatic brain injury patients who were more than 1 year postinjury and who possessed a minimum of 10 degrees extension at the metacarpophalangeal and interphalangeal joints and 20 degrees extension at the wrist of the affected arm (minimum motor criterion).

7 158 Taub, Crago, and Uswatte The patients were asked to wear a sling on the unaffected ann all day for 2 weeks, except during a half-hour exercise period and sleeping hours. The patients demonstrated significant but small improvements in speed or force of movement, depending on the task, on 19 out of 21 tasks on the Wolf Motor Function Test (WMFF; Taub et al., 1993; Wolf, Lecraw, Barton, & Jann, 1989), a laboratory test involving simple upper extremity movements. There was no report of whether the improvements transferred to the life situation. Taub et al. (1993) applied both the paretic ann training and contralateral arm restraint portions of the treatment protocol (Taub, 1980) to the rehabilitation of chronic stroke patients with an upper extremity hemiparesis in a study that used an attention-placebo control group and emphasized transfer of therapeutic gains in the laboratory to the life situation. Four treatment participants signed a behavioral contract in which they agreed to wear a sling on their unaffected ann for 90% of waking hours for 14 days. On 10 of those days, the treatment participants received 6 hours of supervised task practice using their affected arm (e.g., eating lunch; throwing a ball; playing dominoes, Chinese checkers, or card games; writing; pushing a broom, and using the Purdue Dexterity Board and Minnesota Rate of Manipulation Test) interspersed with 1 hour of rest. Five control participants were told they had much greater movement in their affected limb than they were exhibiting, led through a series of passive movement exercises in the treatment center, and given passive movement exercises to perform at home. All experimental and control participants were at least I-year poststroke (mean = 4 years) and had passed the minimum motor criterion before intake into the study. Treatment efficacy was evaluated using the WMFT, the Arm Motor Ability Test (AMAT; Kopp et al., 1997; McCulloch et al., 1988), and the Motor Activity Log (MAL; Taub et al., 1993), which tracks ann use in 14 ADL through a semistructured interview. The treatment group demonstrated a significant increase in motor ability as measured by both laboratory motor tests (WMFT, AMAT) over the treatment period, whereas the controls showed no change or a decline in arm motor ability. On the MAL, the treatment group showed a very large increase in real-world arm use over the 2-week period and demonstrated a further small increase in use when tested 2 years after treatment; the control participants exhibited no change or a decline in arm use over the same period. These results have since been confirmed in an experiment using unaffected ann constraint and shaping of the affected arm, instead of task practice, with a larger sample (20 participants) and a more credible control group (15 participants to date). The shaping procedure involved selecting tasks that were tailored to address the motor deficits of the individual patient, helping the patient to carry out parts of a movement sequence if they were incapable of completing the movement on their own at first, and providing explicit verbal feedback for small improvements in task performance (Taub, Pidikiti, DeLuca, & Crago, 1996). Modeling and prompting of task performance were also used. The control group was designed to better control for the duration and intensity of the therapist-patient interaction and the duration and intensity of the therapeutic activities. The treatment participants signed a behavioral contract agreeing to wear a sling on

8 Constraint-Induced Movement Therapy 159 their unaffected arm for 90% of waking hours for 14 consecutive days and received shaping of affected arm use for the 10 weekdays of that period. The control participants received a general fitness program in which they performed strength, balance, and stamina training exercises; played games that stimulated cognitive activity; and practiced relaxation skills for 10 days. As in the first experiment, the treatment group demonstrated a significant increase in motor ability as measured by the WMFT over the intervention period, whereas the control participants did not. On the MAL, the treatment group showed a very large increase in real-world ann use from pretreatment to follow-up 4 weeks after treatment; the control group did not exhibit a significant change over the same period. The control subjects' answers to an expectancy and self-efficacy questionnaire about their expectations for rehabilitation prior to the control intervention and their reported increase in quality of life after the intervention, as measured by the MOS 36-Item Short-Form Health Survey (Ware & Sherbourne, 1992), suggested that they found the control intervention to be credible. Other experiments have indicated that there is family of techniques that can overcome learned nonuse (Taub, Pidikiti, DeLuca, & Crago, 1996; Taub & Wolf, 1997). The other interventions that have been tested are: (a) placement of a half-glove on the less affected arm as a reminder not to use it and shaping of the paretic arm, (b) shaping of the paretic arm only, and (c) intensive physical therapy (e.g., aquatic therapy, neurophysiological facilitation, and task practice) of the paretic arm for 5 hours a day for 10 consecutive weekdays. Our laboratory designed the half-glove intervention so that CI Therapy could be used with patients who have balance problems and might be at risk for falls when wearing a sling; this intervention expands the population of stroke patients amenable to CI Therapy threefold. We currently use a "padded safety mitt" that leaves the unaffected arm free, so as not to compromise safety, but that prevents use of the hand and fingers in ADL. The shaping-only intervention was tested to evaluate the relative importance of the constraint and task-practice components of the intervention. The intensive physical therapy intervention did not involve physical constraint of the unaffected ann; however, the participants were requested to not make use of their unaffected ann, and this regimen was monitored. To our knowledge, such a concentrated application of physical therapy had not been evaluated before this trial. All these groups showed very large increases in arm use in the life situation over the treatment period equivalent to that observed for the sling-constraint and task-practice and the sling-constraint and task-shaping groups. Two years after treatment, however, these three groups showed some decrement in arm use, whereas the sling-constraint and task-practice-shaping groups did not. The sling-plus-shaping results have been replicated in full studies in two laboratories (Kunkel, Kopp, Taub, & Flor, 1997; Sommer, Bauder, Miltner, & Taub, 1997) and in pilot data elsewhere (Desai, 1991; Koelbel et al., 1997; G. Lavinder, J. Charles, & A. Gordon, personal communication, June-August, 1997; Tries, 1991). The sling-plus-task-practice results have been replicated in pilot studies with subacute stroke patients who are 3-6 months poststroke (D. Nichols, C. Giuliani, C. Winstein, S. L. Wolf, personal communications, September-

9 160 Taub, Crago, and Uswatte December, 1997). Whether CI Therapy techniques will produce similar positive results in acute inpatients remains to be determined. The question arises as to the common factor or factors underlying the therapeutic effect in these different interventions. Although most of the techniques involve constraining movement of the less affected arm, the shaping-only and intensive-physical-therapy interventions do not. There is thus nothing talismanic about use of a sling or other constraining device on the less-affected extremity. The common factors appear to be attention to the paretic limb and repeatedly practicing use of the paretic arm. It is likely that it is these two factors that give rise to the use-dependent cortical reorganization visualized by Liepert et al. (in press), which is presumed to be the basis for the long-term increase in the amount of use of the more affected extremity. Lower Functioning Patients Until recently, the patients we worked with all met or exceeded the minimum motor criteria of 20 degrees of extension at the wrist and l0 degrees of extension of the fingers. This represents a relatively high initial level of motor ability. It is estimated that approximately 20 to 25% of the chronic stroke population meet this motor criterion (Wolf & Binder-Macleod, 1983). However, current work with lower functioning patients is proving to be very promising, suggesting that CI Therapy may be applicable to up to 50% of the stroke population with a chronic unilateral motor deficit. The minimum motor criterion for inclusion of lower functioning patients into therapy is 10 degrees extension of the wrist, 10 degrees abduction of the thumb, and 10 degrees extension of any two other digits. Eight patients whose initial motor ability fell below the minimum motor criterion for the higher functioning group and above the minimum criteria for the lower functioning group have been given CI Therapy to date. All eight of these lower functioning patients exhibited substantial improvement. While the final level was somewhat lower than that of the higher functioning patients, since the lower functioning patients started from a lower initial level of motor ability, the relative change was as large as in the higher functioning patients. These data suggest that the motor capacity of chronic patients is modifiable in a larger percentage of the population than our research originally indicated. New Methods in Treatment-Outcome Measurement CI Therapy successfully transfers improvement in the quality and amount of arm use from the clinic to the life setting (Duncan, 1997; Taub et al., 1993). The current consensus in the rehabilitation field, including the perspectives of patients, researchers, clinicians, and health care payers, is that functional activity in the life situation is the most important outcome to pursue and measure (Keith, 1995). Physical-rehabilitation outcome-evaluation instruments, however, do not provide a direct measure of motor function in the real world (Uswatte & Taub, in

10 Constraint-Induced Movement Therapy 161 press). Traditional instruments in physical rehabilitation focus on measuring strength, flexibility, and coordination in the clinic or laboratory situation (Smith & Clark, 1995). More recent instruments measure functional ability in the home indirectly by clinician observation of activities of daily living performed in the laboratory or clinic (Baxter-Petralia, Bruening, Blackmore, & McEntee, 1990; Cress et al., 1996; Holbrook & Skilbeck, 1983), but the relationship between performance on these instruments and performance in the life situation has not been rigorously tested (Keith, 1995). When investigators have attempted to measure behavior in the home, they have relied on retrospective, self-report questionnaires and focused on functional independence rather than extremity function (Katz, Downs, Cash, & Grotz, 1970; Keith, Granger, Hamilton, & Sherwin, 1987; Mahoney & Barthel, 1965). The experimental work conducted by this laboratory and the observations of others (Andrews & Stewart, 1979) suggest that laboratory motor tests indicate a rehabilitation patient's maximum motor ability, but that patients frequently do not make full use of that ability in the life setting. There is frequently a very large gap between the two. Our laboratory, consequently, has developed new instruments, the MAL and the Actual Amount of Use Test (AAUT), that measure upper extremity function in the life situation (Uswatte & Taub, in press). The MAL (Taub et al., 1993; Uswatte & Taub, in press) is a semistructured interview during which respondents are asked to rate how much and how well they use their affected arm for 14 ADL in the home over a specified period. The MAL is administered independently to the patient and an informant. The tasks include such activities as brushing teeth, buttoning a shirt or blouse, and eating with a fork or spoon. The AAUT (Taub, DeLuca, & Crago, 1996; Morris, Crago, DeLuca, Pidikiti, & Taub, 1997; Uswatte & Taub, in press) is an observational test that measures how much patients spontaneously use their affected arm to perform a set of tasks in the laboratory. It is administered on first entrance into the laboratory before pretreatment testing and just prior to posttreatment testing. Patients are videotaped as they are unobtrusively led through a standardized scenario of 20 tasks that they might encounter in the clinic on a regular basis (e.g., remove coat, place project card in wallet, fill out form). Patients are not told that they are being videotaped during test administration; however, they gave informed consent to be videotaped prior to entry into the CI Therapy trial. In addition, they are not prompted as to which arm to use to accomplish the tasks or informed that they are being tested. Clinicians who are unaware of the patients' treatment condition use the videotape to rate the patients' behavior on the amount of arm use. The patients' performance on the AAUT is believed to be more closely related to how much they actually use their affected arms in their daily lives than their performance on laboratory tests of motor ability where an experimenter specifically asks them to perform tasks with their affected arm. A third real-world outcome measure we are developing is the use of accelerometry to measure arm use objectively and directly in the home (Uswatte & Taub, in press). The accelerometers used in our laboratory are plastic units about the size and weight of a large wristwatch that are based on piezoelectric crystal technol-

11 162 Taub, Crago, and Uswatte ogy. When the piezoelectric crystal in the accelerometers is subject to acceleration, it deforms and produces a charge. This charge is digitized, summed over a user-specified epoch, and reported as a whole number each epoch (Computer Science Applications, 1996; Tryon & Williams, 1996). We propose to have patients wear accelerometers on each arm and the hip before, during, and after treatment. Recordings from the affected arm unit will be compared before and after treatment to evaluate the change in the amount of ann movement due to treatment. Recordings from the unaffected ann unit during treatment will be used to monitor compliance with the constraint protocol while recordings from the hip unit before and after treatment will be used to assess the impact of the intervention on general physical activity. Two initial experiments with college students in a laboratory setting suggested that the accelerometers (a) provide reliable measures of simple and ADL-like arm movement, (b) display high sensitivity to movement parallel to the x and y axes of the units and low sensitivity to movement parallel to the z axis, and (c) possess high sensitivity to changes in the duration and speed of arm movement and low sensitivity to changes in distance (Uswatte et al., 1997). We have also developed two tests of upper extremity motor ability in the laboratory of specific value for evaluating the population of chronic stroke patients we study. The WMFT was first developed in the laboratory of Steven Wolf and has been modified by the current group (Taub et al., 1993). The WMFF measures the ability of patients to perform 19 simple limb movements and tasks with the affected ann. Two of the items measure strength and 15 items are timed and scored by raters blinded to the pre- or posttreatment status of the patient. The items include activities such as lifting the affected arm from the test table surface to a box, extending the elbow past a line 40 cm from the initial position, turning over playing cards, and picking up a pencil. The AMAT (Kopp et al., 1997; McCulloch et al., 1988; Taub et al., 1993), measures the ability of patients to perform 13 ADL with the affected arm. Each of the 13 tasks is a complete ADL commonly carried out in the life setting, such as putting on a sweater, dialing a telephone number, and unscrewing a jar cap. FUTURE APPLICATIONS The range of disorders for which CI Therapy might be an effective treatment encompasses conditions in which motor disability is in apparent excess of the underlying pathology. A possible explanation for the excess motor disability in some of these cases might be that it is being maintained by learned nonuse (Taub, 1994). The research with deafferented monkeys suggests that learned nonuse is established whenever (a) 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 (b) 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 conditioned in the acute phase remains in force. Some preliminary studies suggest that the range of disorders that meet these

12 Constraint-Induced Movement Therapy 163 stipulations is wide. Research with monkeys suggests that excess motor disability can occur following pyramidotomy and other motor lesions (Chambers, Konorski, Liu, Yu, & Anderson, 1972; Lashley, 1924; Ogden & Franz, 1917; Tower, 1940). The study in which Wolf et al. (1989) reported improved motor performance in patients with a unilateral upper extremity hemiparesis after CI Therapy treatment included traumatic brain injury patients. This suggests that excess motor disability occurs after traumatic brain injury and can be overcome by CI Therapy techniques. Positive results obtained with CI Therapy by Crocker, MacKay-Lyons, and McDonnell (1997) with a 2-year-old with a hemiparesis due to cerebral palsy and by our laboratory (DeLuca, Crago, & Taub, 1997) with a teenager with a hemiparesis due to perinatal stroke suggest that excess motor disability occurs in children with cerebral palsy. A case study by Birbaumer and Taub (1994), which described restoring ambulation in a 29-year-old woman who was 6 months post spinal cord injury using a CI Therapy approach, suggests that excess motor disability in the lower extremities occurs after SCI. Our laboratory has currently begun using a CI Therapy approach for improving ambulation in chronic stroke. The first three patients have exhibited, if anything, greater improvement than our patients treated for upper extremity motor deficit (Spear, Yakley, & Taub, 1998). Given these results and theoretical considerations, additional disorders where CI Therapy might prove effective include peripheral nerve damage, unused or underused prosthetic limbs, broken hip, and arthritis during periods of remission (Taub, 1980, 1994). Another area for future research is the prevention of learned nonuse. Preliminary magnetic resonance imaging (MRI) data collected by Chatterjee, Edwards, Uswatte, and Taub (1997) suggest that in chronic stroke patients with an upper extremity hemiparesis there may be an association between the locus of the infarct and the affected arm motor ability. If the initial findings are confirmed, MRIs, obtained after an infarct can be visualized in the scans in the early poststroke period, could serve to identify patients who are likely to regain motor control of their arm in the chronic phase and provide such patients with treatment in the acute phase that prevents the development of learned nonuse (Uswatte & Taub, in press). IMPLICATIONS FOR THE DELIVERY OF PHYSICAL THERAPY SERVICES Conventional physical therapy is usually administered only once or twice per week on an outpatient basis; but even when it is administered every day, individual treatment sessions last just 0.5 to 1 hour each. When stroke survivors are rehabilitation inpatients in the subacute period, they typically receive at least 3 hours of therapy daily. However, the treatments cover so wide a range of areas (e.g., speech therapy; cognitive retraining; and therapy for the lower extremity, for

13 164 Taub, Crago, and Uswatte the upper extremity, and for transfers) that repetitive practice is not given in any particular type of motor function. As noted in the introduction, controlled studies evaluating traditional physical therapy interventions, which typically involve relatively little repetitive practice, have not yielded positive findings. As described above, applying the family of CI Therapy techniques produces very large increases in the amount of arm use of chronic and subacute stroke patients in their daily lives. In addition, when conventional physical therapy is administered for 6 hours/day for 10 consecutive weekdays, there is a similar increase in arm use over the treatment period. This suggests that the factor underlying the difference in results between CI Therapy and traditional techniques does not reside primarily in the nature of the therapy, but rather in its frequency of delivery. This conclusion implies that some chronic and subacute stroke patients could benefit greatly from physical therapy if they received treatment for multiple hours per day over consecutive days (Duncan, 1997; Taub & Wolf, 1997). Although the motor-learning literature suggests that massed practice has a neutral or negative effect on the learning of continuous tasks and a variable effect on the learning of discrete tasks (Schmidt, 1988), recent studies with neurologic patients from the laboratory of Mauritz, in which large therapeutic effects for lower extremity function were obtained with repetitive concentrated interventions (Butefisch, Hummelsheim, Denzler, & Mauritz 1995; Hesse, Bertelt, Schaffrin, Malezic, & Mauritz, 1994), support the repetitive training model of CI Therapy. We recognize that it is difficult to alter customary methods of delivering therapeutic services because of the tendency to remain with what is known, the existence of administrative structures designed to manage the current model of delivery efficiently, and the very real consideration of what services payment agencies are willing to reimburse. However, none of these constitute insuperable barriers. What is being proposed here is not a change in therapeutic practice per se; very little that is used in conducting CI Therapy is unfamiliar to physicalrehabilitation professionals. Instead, the proposal is to (a) identify, provide, and reimburse treatment for subacute and chronic stroke patients who are amenable to therapy involving repetitive practice and (b) change the schedule of treatment for these patients so that they receive concentrated and repetitive training. The suggestion is not to discard the "3-hour rule" and training in varied activities, but rather to extend treatment for those patients who have the stamina to carry out further therapeutic exercises. The additional time would be spent in repetitive practice of specific types of movement and would continue until an apparent plateau of function had been reached, at which point training would be switched to another part of the body or motor function. If patients cannot tolerate more than 3 hours of therapy daily, it would be advantageous to defer inpatient treatment or prescribe outpatient treatment when they gain the requisite stamina. The data from the CI Therapy literature and other recent work speak very clearly on the value of this approach.

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19 170 Taub, Crago, and Uswatte measurement of extremity use at home [Abstract]. Rehabilitation Psychology, 42, 139. Uswatte, G., & Taub, E. (in press). Constraint-induced movement therapy: New approaches to measurement in physical rehabilitation. In D. T. Stuss, G. Winocur, & I. H. Robertson (Eds.), Cognitive neurorehabilitation: A comprehensive approach. New York: Cambridge University Press. Ware, J. E., & Sherbourne, C. D. (1992). The MOS 36-Item Short-Form Health Survey (SF-36). I. Conceptual framework and item selection. Medical Care, 30, Wolf, S. L. (1983). Electromyographic biofeedback applications to stroke patients: A critical review. Physical Therapy, 63, Wolf, S. L., & Binder-Macleod, S. A. (1983). Electromyographic biofeedback applications to the hemiplegic patient: Changes in upper extremity neuromuscular and functional status. Physical Therapy, 63, Wolf, S. L., Lecraw, D. E., Barton, L. A., & Jann, B. B. (1989). Forced use of hemiplegic upper extremities to reverse the effect of learned nonuse among chronic stroke and head-injured patients. Experimental Neurology, 104, Acknowledgments. This research was supported by Grant HD from the National Institutes of Health, Grant from the Retirement Research Foundation, and a grant from the Center for Aging, University of Alabama at Birmingham, to Edward Taub and Grants B93-629AP and B95-975R from the Rehabilitation Research and Development Service, U.S. Department of Veterans Affairs, to Rama D. Pidikiti and Edward Tanb. We would like to thank the following collaborators: Rama D. Pidikiti, Anjan Chatterjee, Stephanie C. DeLuca, David Morris, Sharon Shaw, Edwin W. Cook, Wolfgang Miltner, Bruno Kopp, Maneesh Varma, Seth Spraggins, Scott Moran, Harrison Walker, Vinayak Sharma, Jesse Calhoun, Kim Rudolph, David Edwards, Francilla Allen, Jennifer Glasscock, Louis D. Burgio, Donna M. Bearden, Thomas E. Groomes, William D. Fleming, Cecil S. Nepomuceno, and Neal E. Miller. We would also like to thank Drs. Scott Richards, Thomas Novack, and Jay Meythaler for their critical reading of the manuscript and for their helpful suggestions. Offprints. Requests for offprints should be directed to Edward Taub, PhD, Department of Psychology, University of Alabama, CH415, 1300 University Boulevard, Birmingham, Alabama