Constraint-induced movement therapy (CI, CIT, or CIMT)
Constraint-induced movement therapy (CIMT) is a rehabilitation approach designed to enhance the use of limbs in individuals with movement impairments, primarily targeting those who have suffered strokes, traumatic brain injuries, or conditions such as multiple sclerosis and hemiplegia. The therapy works by restricting the use of the unaffected limb, often through slings or mitts, while encouraging the patient to utilize the affected limb exclusively during the therapy period, typically lasting two to three weeks. This method seeks to combat a phenomenon known as "learned non-use," where a person stops using a weakened limb because it feels easier to rely on the unaffected one.
CIMT incorporates intensive training sessions focusing on repetitive tasks that help rewire the brain and regain mobility in the affected limb. Modified versions of this therapy exist, such as modified CIMT (mCIMT), which involves less daily practice. Research indicates that CIMT can lead to structural changes in the brain, enhancing areas associated with limb movement, suggesting that the therapy promotes neuroplasticity. Although primarily used post-injury, CIMT can be effective even years after the onset of limb control loss, emphasizing the importance of early and continuous engagement in rehabilitation efforts.
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Constraint-induced movement therapy (CI, CIT, or CIMT)
Constraint-induced movement therapy (CIMT) is a series of rehabilitation techniques to help patients improve the ability to use limbs. CIMT has been used in patients with a variety of medical issues, including those who have experienced strokes or traumatic brain injury, individuals with multiple sclerosis, and children with hemiplegia, or unilateral cerebral palsy, which means paralysis of one side of the body.
CIMT involves limiting the patient's use of the limb that is less affected—for example, by putting the less affected arm in a sling or mitt for most of the day—and having the patient use the other limb almost exclusively for two to three weeks. The patient also receives several hours of training using the more affected limb daily. Another treatment, modified CIMT (mCIMT), is similar but includes less daily training while the more affected limb is restricted.
Studies have found that CIMT can have an effect on the brain. Imaging studies show that areas of the brain related to moving the more affected limb grow in patients engaged in CIMT. This has been described as a rewiring of the brain.
Background
CIMT is based on the research of behavioral neuroscientist Edward Taub and others at the University of Alabama at Birmingham. Taub first began the work earlier, however. He was a graduate student at Columbia University when he conducted laboratory work in a research institute at the Jewish Chronic Disease Hospital in New York. Researchers operated on monkeys to sever the spinal nerve connection allowing them to feel sensation in one or both front limbs. The monkeys used these limbs as supports to move around and to grasp and manipulate items. Although the limbs were not affected in any other way—they still operated as before—the monkeys stopped using the limbs that lacked sensation.
Researchers persuaded the monkeys to use the affected limbs through several conditioning techniques. For example, the monkey could learn to move the limb when it hears a sound, such as a buzzer, because if it failed to move the limb, it received a small electric shock. Taub and the other researchers also tried a restraint method—the unaffected limb was restrained using a straitjacket, so the monkey could not use it, but the affected limb was left free. If the monkey did not use the affected limb, it was more or less helpless. Food was placed outside of the monkeys' cages. Researchers found that within a few hours, the monkeys began to use the unbound limbs. They reached out to pick up the food and managed to feed themselves. Some of the monkeys began using the unbound limbs to support their bodies as they moved around their cages. Their movements were clumsy, because they did not have sensation in the limbs, but they were able to function well. After one week with the unaffected limbs bound, the monkeys continued to use the limbs that did not have sensation. This behavior continued and was found to be permanent. Taub and his colleagues began to publish papers on their monkey studies during the 1960s, although the work continued for decades.
The researchers worked to build on knowledge from earlier studies. Previous studies had concluded that without sensory input, a living creature could not move or use its limbs. Taub's research clearly proved this to be untrue. The work also disproved ideas about the adult brain. Previously, researchers believed only immature brains could adapt—they had what is called plasticity—but the monkey experiments showed that adult primate brains were not rigid and set.
Researcher Larry Anderson, who had observed Taub's work, attempted to translate Taub's findings to human patients in 1967. Anderson immobilized the unaffected arms of three stroke patients. He sounded a tone. Patients who did not move their affected but unbound arms received mild electric shocks. After some success with his small study, Anderson applied his work to a larger group of twenty-four stroke patients. All of the patients in this group saw improvement in their affected limbs. Taub began a series of his own experiments using human stroke patients in 1986.
Overview
CIMT is based on learned non-use. This is the idea that when a person does not use a limb, the person's brain forgets how to use it.
Learned non-use often arises when an individual does not try to use a weakened limb because it is just easier to use the other one. The less the affected limb is used, the greater the loss of mobility as the brain forgets how to use it; this leads the person to rely even more on the other limb, creating a cycle of non-use. This prevents the individual from regaining strength in and use of an affected limb.
CIMT helps to counteract learned non-use by forcing the individual to use the affected limb. This use helps the brain relearn how to operate the limb. Physical therapists have found that the adage "use it or lose it" is true in recovery, and patients must use the affected limbs regularly to rewire the brain and regain control of the limbs.
Many stroke patients need to relearn how to use an affected arm and hand. A physical therapist often begins working with a stroke patient by restraining the functional arm for 90 percent of the patient's waking time. Next, the therapist puts a mitt on a stroke patient's functional hand for several hours a day. The patient performs repetitive tasks using the affected, free hand. This helps the brain repair the pathways required to use the limb. These repetitive tasks involve shaping, or adaptive task practice (ATP). This means the therapist breaks tasks down into manageable pieces, then changes one part of it at a time. For example, making a telephone call involves picking up the handset and dialing a number. Shaping might involve learning to grasp the handset first. After the patient repeatedly practices this action, the therapist might have the patient grasp the handset and bring it to his or her ear. After repeatedly practicing these steps, the patient would add another step, and so on.
When used soon after the event that caused paralysis, such as a stroke, CIMT can prevent patients from developing learned non-use. CIMT has been found to be effective even long after patients have experienced loss of limb control, however. Physical therapists advise patients to begin therapy no matter how much time has passed.
Bibliography
"CI Therapy Research Group." University of Alabama at Birmingham Department of Psychology, www.uab.edu/citherapy/. Accessed 29 Nov. 2017.
"Constraint Induced Movement Therapy." Children's Hemiplegia and Stroke Association, chasa.org/treatment/constraint-induced-movement-therapy/. Accessed 29 Nov. 2017.
"Constraint Induced Movement Therapy." Physiopedia, www.physio-pedia.com/Constraint‗Induced‗Movement‗Therapy. Accessed 29 Nov. 2017.
"Edward Taub, PhD." American Psychological Association, www.apa.org/action/careers/health/edward-taub.aspx. Accessed 29 Nov. 2017.
McDermott, Annabel. "Constraint-Induced Movement Therapy—Upper Extremity." Heart & Stroke Foundation Canadian Partnership for Stroke Recovery, 22 Sept. 2016, www.strokengine.ca/intervention/constraint-induced-movement-therapy-upper-extremity/. Accessed 29 Nov. 2017.
"Neurological Rehabilitation." Johns Hopkins Medicine, www.hopkinsmedicine.org/healthlibrary/conditions/physical‗medicine‗and‗rehabilitation/neurological‗rehabilitation‗85,P01163. Accessed 29 Nov. 2017.
Schwartz, Jeffrey M., and Sharon Begley. The Mind and the Brain: Neuroplasticity and the Power of Mental Force. HarperCollins, 2002, pp. 138–62.
Taub, Edward. "The Behavior-Analytic Origins of Constraint-Induced Movement Therapy: An Example of Behavioral Neurorehabilitation." Behavioral Analysis, vol. 35, no. 2, Fall 2012.
Wolf, Steven L., et al. "The EXCITE Stroke Trial: Comparing Early and Delayed Constraint-Induced Movement Therapy." Stroke, vol. 41, no. 10, Oct. 2010, pp. 2309–15.