Stroke rehabilitation - constraint-induced movement therapy

Summarized by Robert W. Griffith, MD
June 16, 2000 (Reviewed: December 11, 2002)

Introduction

Constraint-induced movement therapy (CI therapy) is the term applied to a series of rehabilitation techniques championed by researchers at the University of Alabama, USA, and the Friedrich-Schiller University, Jena, Germany. Recently the technique has gained further credibility by a report that it is associated with a measurable long-term alteration in brain function, using focal transcranial magnetic stimulation mapping.

For the upper limb, CI therapy involves inducing the use of the more-affected side for a target of 90% of the waking hours by using one of several methods of constraint of the less-affected arm. Concentrated, repetitive training of the affected limb is given for 6 hours a day for a 2-3 week period. For lower-limb paresis the procedure is the same, but without constraint of the lesser-affected leg.¹

Several small studies have shown the effectiveness of CI therapy in chronic stroke patients, when the motor defect is stabilized; substantial long-term improvement has been achieved.² The technique has also been used effectively in musicians with another cortical disorder, focal hand dystonia.³

The study summarized here was designed to use CI therapy as a model to assess therapy-induced neuronal plasticity in stroke patients. Clinical effectiveness was not a prime target of the study, so that no control group was considered necessary.

Method

Thirteen patients with hemiparesis of mean duration 4.9 years were studied. Ten were men, and the mean age was 56.7 years. Eleven had a right-sided paresis; 3 were cortical lesions (2 ischemic, 1 hemorrhagic) and10 had lacunar subcortical lesions in the internal capsule.

CI therapy was given for 12 days, preceded and followed by electrophysiological and behavioral tests. Constraint consisted of wearing a resting hand splint in a 900 sling on the non-paretic side, for 90% of waking hours. On 8 weekdays during the treatment period 6 hours of intensive use of the affected arm was instituted, employing a variety of movements, according to a behavioral technique called "shaping".⁴

The Motor Activity Log (MAL) scale was employed to assess arm use in 20 common, important activities of daily living; testing was done at intervals before and up to 6 months after CI therapy.

Bilateral focal transcranial magnetic stimulation (TMS) mapping was done, measuring the size of the cortical motor output map, motor thresholds, and the location of the "center of gravity" of the output map.

Results

The MAL scores were significantly increased from one day before treatment (mean 2.2) to one day after treatment (mean 3.7, p<0.001). The improvement was maintained at 6 months after treatment.

The TMS mapping data paralleled the MAL results. On the day before treatment, there were 40% fewer active positions on the affected side than on the non-infarcted side (p<0.001), but by the first day after CI therapy this relationship had reversed, with a 37.5% difference in favor of the affected side. Four weeks after treatment, the size of the motor output map on the affected side was still significantly larger than before therapy (p=0.036), while at 6 months both sides were practically equal in size.

The amplitude-weighted center of gravity in the TMS results from the affected side showed significantly greater shifts in a medio-lateral direction, compared with the unaffected side (small shifts were probably due to technological limitations of the method). In 9 cases the shifts were lateral, in 4 they were medial. These shifts were maintained at 4 weeks after therapy.

Comment

The investigators claim that this is the first demonstration in man of a long-term change in brain function that is associated with a treatment-induced improvement in the rehabilitation of movement after stroke injury. In other words, CI therapy led to an increase in the number of neurons related to movement in the stroke-affected limb, situated close to those involved before the start of therapy. They go on to speculate that the technique reduces local infarct-induced inhibitory interneurons, thereby unmasking pre-existing excitatory connections; the short time-course of the changes makes the formation of new anatomic connections by sprouting unlikely.

This study has two important inferences. First, it provides evidence that a successful therapeutic intervention has its foundation in electrophysiological changes that represent cortical neuronal plasticity - something that has been described before in animals and humans.

Second, the technique termed CI therapy has not yet found immediate acceptance in rehabilitation units worldwide. This may, in part, be a reflection of the personnel-intensive physiotherapy demanded. The existence of objective, measurable electrophysiological changes provides confirmation of the significant effects of the technique, and places it on sounder footing. It is to be hoped that additional well-controlled clinical studies will conclusively demonstrate the usefulness of CI therapy, so that it will then be used on a much larger scale. Full rehabilitation after stroke is a worthy objective.

Source

• Treatment-induced cortical reorganization after stroke in humans J. Liepert, H.  Bauder, HR. Miltner,   et al., Stroke, 2000, vol. 31, pp. 1210--1216

Footnotes
1. Constraint-induced movement therapy: a new family of techniques with broad application to physical rehabilitation - a clinical review. E. Taub, G. Uswatte, R. Pidikiti, J Rehab Res Dev, 1999, pp. 237--251
2. Constraint-induced movement therapy for motor recovery in chronic stroke patients. A. Kunkel, B. Kopp, G. Mueller, Arch Phys Med Rehabil, 1999, pp. 624--628
3. Effects of constraint-induced movement therapy on patients with chronic motor deficits after stroke: a replication. WH. Miltner, H. Bauder, M. Sommer, Stroke, 1999, pp. 586--592
4. An operant approach to rehabilitation medicine: overcoming learned nonuse by shaping. E. Taub, JE. Crago, LD Burgio, J Exper Anal Behav, 1994, pp. 281--293

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.