Constraint-Induced Movement Therapy – March 2007

Constraint-induced movement therapy (CIMT) is a physical rehabilitation technique that has been receiving increasing attention in the pediatric rehabilitation community. CIMT was developed based on animal models of sensory deprivation from 1960’s and 70’s. The adaptation of the general procedures (using a restraint to encourage contralateral limb use) to humans initially occurred in adults with hemiparetic stroke, where the majority of published research reports have been focused to date. These initial studies, conducted in the 1980’s, involved “forced use,” or encouraging use of the involved extremity by restraining the non-involved extremity alone or along with conventional physical/occupational therapy. Subsequently, CIMT was conceptualized, which involves intensive targeted practice with the involved extremity along with the restraint (typically 2-3 weeks in duration). Thus, CIMT is an active, task-driven, treatment administered by a trained practitioner, combining principles from the fields of behavioral psychology and motor learning. The results of a recent, randomized, multi-site trial of CIMT indicate CIMT produced clinically relevant improvement in involved upper extremity function in stroke patients (1).

Despite the success of CIMT in adults with stroke to date, there is considerably less evidence of its efficacy in children with hemiplegia. Until recently much of the evidence has been in the form of case studies or small ABA design studies. In the last several years, however, there have been a number of small randomized control trials of CI therapy in children (2). All of these studies to date have suggested efficacy in improving quality and quantity of affected limb use in children with hemiplegia. The research to date has focused on a variety of age groups spanning from ~ nine months to adolescence. Theoretically, the increased plasticity in the developing brain would suggest that efficacy would be greater the earlier CIMT is administered. However, the evidence to date does not support this notion, as efficacy has been shown across all ages. One study even suggests increasing efficacy up until the age of ~4-5 years is likely due to increasing ability of children to stay on task as they mature (and thus increase intensity of treatment) (3). Furthermore, recent evidence suggests that efficacy may be related to severity of hand impairments, with very mild or severe impairments may not be amenable to treatment (4).

Comment:

While the evidence to date is promising, considerably more work is required, including large-scale, multi-site randomized control trials. Most of the studies to date have used differing outcome measures, the types of practice and restraints (e.g., casts, slings, mitts) and varying treatment durations. Since it is not the restraint that induces change, rather it is the environment that is used to solicit intensive practice, there is no evidence supporting the use of more invasive devices such as bi-valved casts. Furthermore, studies of spinal cord tract development in the kitten indicate that restriction of limb use at an early “critical” age may even permanently damage development (5). In light of recent studies suggesting efficacy with modest restraint (using a mitt) for just two hours per day in very young children, long-periods of restraint should not be used until these risks in young children have been determined. Dosing effects need to be determined as well. Both modified (i.e., reduced) schedules and more passive “forced use” paradigms have been shown to be effective in younger children, but the extent to which more intensive and active treatment is required with increasing age is unknown. Furthermore, restraining the unaffected limb without structuring the environment and providing tasks graded to provide success likely leads to frustration as a child attempts to negotiate activities within their normal routine. Left unsupervised, there would be increased risk of injury in the event of loss of balance since the child’s normal protective response would be inhibited.

CIMT should complement, rather than replace, other treatments throughout the child’s long-term pediatric care since it only occurs during a short period. Recent evidence suggests that repeating it may result in cumulative improvements. CIMT was developed to overcome learned non-use in adults with hemiplegia while children with hemiplegia may have never effectively learned to use their involved extremity. Thus CIMT must be modified to be developmentally focused (6). Trained therapists need to understand the concept of CIMT before starting treatment and have theoretical and practical knowledge of motor-learning principles of skill acquisition and motor development, as well as a pedagogical framework regarding how to teach children to learn. One key issue is to start with the end goal in mind. CIMT is a unimanual intervention, and increased functional independence in the child’s environment requires use of both hands in cooperation. Principles of motor learning would suggest that this might be best accomplished by skipping the restraint and practicing bimanual skills directly. The efficacy of such bimanual training remains a promising area for future exploration.

1. Wolf S, Winstein C, Miller J, Taub E, Uswatte G, Morris D, et al. Effect of constraint-induced movement therapy on upper extremity function 3 to 9 months after stroke" The EXCITE Randomized Clinical Trial. JAMA 2006;296:2095-2104.
2. Charles J, Gordon AM. A critical review of constraint-induced movement therapy and forced-use in children with hemiplegia. Neural Plasticity 2005;12:245-262.
3. Eliasson AC, Krumlinde-sundholm L, Shaw K, Wang C. Effects of constraint-induced movement therapy in young children with hemiplegic cerebral palsy: an adapted model. Dev Med Child Neurol 2005;47(4):266-75.Charles et al. 2006
4. Charles JR, Wolf SL, Schneider JA, Gordon AM. Efficacy of a child-friendly form of constraint-induced movement therapy in hemiplegic cerebral palsy: a randomized control trial. Dev Med Child Neurol 2006;48(8):635-42.
5. Friel KM, Martin JH. Role of sensory-motor cortex activity in postnatal development of corticospinal axon terminals in the cat. J Comp Neurol. 2005 Apr 25;485(1):43-56. 
6. Gordon AM, Charles J, Wolf SL. Methods of constraint-induced movement therapy for children with hemiplegic cerebral palsy: development of a child-friendly intervention for improving upper-extremity function. Arch Phys Med Rehabil 2005;86(4):837-44.