Published in UAB Insight, Spring 2007

Challenges conventional wisdom surrounding poststroke recovery

After decades of rigorous research, Constraint-Induced Movement therapy (CIMT), a rehabilitation technique pioneered by UAB behavioral neuroscientist Edward Taub, PhD, has been proven to produce greater improvements in movement and functional use of impaired arms and hands in stroke patients than conventional care, according to the Extremity Constraint Induced Therapy Evaluation (EXCITE) trial (JAMA. 2006;296[17]:2095-2104). CIMT is the first rehabilitation modality to show such progress and dramatically changes how neurological injuries are studied and treated.

Investigators conducted EXCITE, a prospective, single-blind, randomized clinical trial, at UAB and six other academic institutions. In 222 patients who retained some hand and wrist movement 3 to 9 months after a stroke, researchers found 2 weeks of CIMT significantly improved upper extremity function that persisted at 1 year. Investigators randomized EXCITE participants to CIMT or customary care, which ranges from no treatment after formal rehabilitation to pharmacologic or physiotherapeutic interventions. Investigators evaluated patients with the Wolf Motor Function Test, a measure of laboratory time and strength-based functional ability, and the Motor Activity Log, a measure of how well and how often patients perform 30 common daily activities.

Compared with controls, the CIMT group achieved a 34% reduction in time to complete a task; a 65% increase in the proportion of tasks performed spontaneously with the partially paralyzed arm in the life situation; and a greater decrease in self-perceived hand function difficulty.

The Approach
“Constraint-Induced (CI) Movement therapy consists of three components: massing of repetitive, structured, practice-intensive therapy in use of the more-affected arm; restraint of the less-affected arm; and a transfer program, which includes monitoring arm use in life situations and problem solving to overcome perceived barriers to using the extremity,” says Taub, whose UAB team trained EXCITE primary investigators and their staffs at other study sites. Coprincipal investigator of EXCITE’s UAB arm is Gitendra Uswatte, PhD, assistant professor of psychology.

Since completing EXCITE, Uswatte, Taub, and David M. Morris, PhD, PT, associate professor of physical therapy, have further refined CIMT and found that streamlined techniques lead to greater improvements than those studied in the original investigation. CIMT is applicable for those with poststroke hemiparesis in lower extremities, with outcomes mimicking the success of earlier upper-limb studies, and also for those with traumatic brain injury (TBI), cerebral palsy, aphasia, and focal hand dystonia.

Therapists customize CIMT techniques for each patient depending on severity of their deficit, but typically include intensive training by behavioral shaping of the impaired arm and hand and wearing a restraining mitt on the less-affected hand for waking hours during the entire 2 or 3 weeks of treatment. People with mild-to-moderate motor impairment after stroke typically spend 3 hours a day in CI therapy for 10 consecutive weekdays. Those with moderate deficits work 3 hours a day for 3 weeks, and those with moderately severe deficits work 6 hours a day for 3 weeks.

“Repetitive tasks are undoubtably crucial to CIMT’s success, yet recent UAB studies have shown the component that engenders the most clinically significant improvements is the transfer package,” Uswatte says. “We use a home diary, questionnaire, and 30-minute daily discussions that focus on identifying and surmounting patients’ perceived barriers to using their impaired arm in everyday life. For example, a patient may admit he has not lifted his glass of water, not because of the ‘learned nonuse’ that stroke patients develop, but from fear he will spill it. Therapists help patients solve such problems, perhaps suggesting they fill a glass only one-quarter full to encourage frequent, repetitive movement of affected limbs and produce greater range of motion.”

Challenging Convention
An editorial accompanying Taub’s JAMA article noted that EXCITE is a well-designed randomized clinical trial that suggests more recovery after stroke is possible than traditionally thought. “Despite decades of research and discovery, researchers still have no clear idea as to the maximal amount of benefit with interventions that harness the learning powers of the human brain.”

Taub’s work stems from his basic research with monkeys. He began translating techniques he developed with monkeys to chronic stroke patients when he learned medical literature suggested it was highly unlikely their motor capacity was modifiable. “We knew a small placebo-controlled study would suggest CIMT’s therapeutic significance if we could show improvement in affected limbs in chronic stroke patients who were expected to have little or no recovery of motor function either spontaneously or with the application of any known rehabilitation therapy,” he says.

Historically, rehabilitation specialists reported patients improved little or not at all after the first year following stroke or brain injury, and traditional teachings maintained that brain plasticity occurred only in the immature nervous system, ceasing at about age 12 years. “This was virtually an axiom in neuroscience and rehabilitation medicine, and it went unchallenged, in part because no physical rehabilitation studies had ever shown substantial motor improvement more than 1 year after neurological injury,” Taub says. “Yet we have repeatedly shown CI therapy produces massive brain plasticity and cortical reorganization in adult patients months to decades after injury. When CI therapy studies began finding large changes in motor ability, it was obvious that neurological changes also must be occurring.”

Studies involving a variety of brain imaging and mapping techniques, including transcranial magnetic stimulation, functional magnetic resonance imaging, positron emission tomography, and source imaging with electroencephalography and magnetoencephalography have now validated the clinically observed behavioral improvements in CIMT. These investigations show excitability, metabolic, or other functional changes in the brain. Taub, Uswatte, collaborator Victor W. Mark, MD, and graduate students Lynne V. Gauthier and Christi E. Perkins are examining the brain’s anatomical structure before and after CIMT. UAB studies, replicated in many laboratories, find the brain area responsible for limb movements shrinks by half in chronic stroke patients. CIMT doubles the size of the involved brain area. “Future studies will help establish a time course for poststroke shrinkage and demonstrate ability of CI therapy to return the motor cortex to its prestroke size so it equals the corresponding area on the healthy side of the brain,” he says.

Beyond Stroke
Morris, Sharon E. Shaw, DrPH, PT, Staci B. McKay, and others have found that CI therapy produces equivalent improvements in TBI and stroke patients. Mark and other team members are studying CIMT for slowly progressing multiple sclerosis and, with a grant from the National Institute of Disability and Rehabilitation Research awarded to Uswatte, for patients with completely paralyzed hands. To customize CIMT for patients with fully plegic hands, Mary H. Bowman, MS, OTR, Camille C. Bryson, MS, PT, and other therapists incorporate techniques from neurodevelopmental and other therapies, such as light weight-bearing exercises, stretching, tapping, and applying ice, all of which reduce spasticity and allow flickers of movement that form a basis for motor training.

Taub encourages referrals of patients with affected limbs following TBI or stroke, but notes people with uncontrolled hypertension must work with their primary care providers to control their blood pressure before initiating CIMT.

Because CIMT laboratory studies for patients with specific requirements are funded by NIH grants, such treatment costs participants nothing. Therapy also is available through the Taub Therapy Clinic on a fee-for-service basis for anyone the data indicate may benefit. Eventually CIMT provided by automated workstations developed by Taub’s group and the Birmingham Veterans Affairs Medical Center may be available at reduced costs.

Up to 85% of the 566,000 stroke survivors in the United States experience hemiparesis immediately after stroke, and upper-extremity functional limitations persist in more than half of patients 3 to 6 months later. In about one third of stroke cases, someone, typically a spouse, must quit their job to care for the patient full time. UAB’s Stephen T. Mennemeyer, PhD, in collaboration with Uswatte, Taub, and physical therapist assistant Sonya Pearson, has found that two thirds of those who left their jobs to provide care returned to work after CIMT. With evidence showing CIMT is cost-effective, insurance providers may begin to embrace the concept.

“Up to 97% of our chronic stroke patients experience substantial, significant, clinically meaningful improvements,” Taub says. “With CI therapy, there is now more than hope.”

For more information:
Dr. Edward Taub
1.800.UAB.MIST
mist@uabmc.edu