RN/Thomson AHC Home Study Program CE CENTER

Originally posted February 2005

By Ellen Barker, RN, MSN, CNRN, APN

ELLEN BARKER is an advanced practice nurse in private practice, a neuroscience clinical specialist, and the president of Neuroscience Nursing Consultants in Greenville, DE. She is a member of the RN editorial board and an educational consultant for Medtronic, Inc.

A new therapy offers hope that movement will be restored to weakened limbs following a stroke.

Stroke is the No. 1 cause of serious adult disability in the United States.¹ Each year, more than 700,000 Americans suffer a stroke, and about two-thirds of them survive and require rehabilitation.² Not surprisingly, the road "back" can be arduous.

Stroke frequently causes motor deficits from damage to the brain. Weakness or paralysis of one side of the body, a common disability following stroke, may cause problems with the simplest of daily activities, such as walking, dressing, eating, and using the bathroom.

With conventional rehabilitation therapy for stroke, patients typically learn to compensate for their disability by using the functioning, rather than the impaired, limbs.³ However, a new and promising neurorehabilitation technique called constraint-induced movement therapy (CIMT), pioneered by Edward Taub, a psychology professor at the University of Alabama at Birmingham (UAB), takes a different approach. Also known as "forced use," CIMT emphasizes the use of the limb disabled by the stroke. By constraining the unaffected limb, it forces patients to actively use the affected limb, the goal being to maximize or restore its motor function. This type of therapy may even encourage a reorganization of brain cells—a theory that's still under study.

To understand the concept underlying CIMT, it helps to understand the physiologic processes that occur during and after stroke. It's also helpful to know what the research on CIMT is showing, since this type of therapy is still relatively new.

What happens during a stroke

When a stroke occurs, the blood supply to part of the brain is suddenly interrupted. It can result from thrombus formation or embolism (ischemic stroke), or when a blood vessel in the brain ruptures, with bleeding into the brain tissue or the subarachnoid space (hemorrhagic stroke). In the same way that a person suffering a loss of blood flow to the heart is said to be having a heart attack, a person with a loss of blood flow to, or sudden bleeding in, the brain can be said to be having a "brain attack."^1,4

Brain cells die when they no longer receive oxygen and nutrients from the blood or when they are damaged by sudden bleeding in the brain. Cerebral ischemia is the term used to describe the loss of oxygen and nutrients to brain cells as a result of inadequate blood flow. Prolonged ischemia leads to infarction, or cell death; the dead brain cells are eventually replaced by a fluid-filled cavity, or infarct.

When blood flow to the brain is interrupted, some brain cells die immediately, while others, though damaged, remain salvageable. These damaged cells make up the "ischemic penumbra," and can linger in this compromised state for several hours. The current thinking is that if blood flow is restored, some of these cells can be saved and may become functional again. In ischemic stroke, restoring blood flow to damaged cells may be achieved by administering the clot-dissolving agent , tissue plasminogen activator (t-PA) within three hours of the start of the stroke.^1,4

But t-PA isn't always given in time, it's not always effective, and it's not indicated for all types of stroke or all patients. So, despite t-PA, loss of function is still a reality for many stroke patients.

A natural rewiring of the brain

Advances in imaging and rehabilitation have shown us that the brain can compensate for function lost as a result of stroke. When cells in an area of the brain responsible for a particular function die after a stroke, the patient becomes unable to perform that function. The plasticity of the brain—its ability to adapt and reorganize—and a natural rewiring of the neural connections make it possible for one part of the brain to change functions and take up the work of the injured part.^1,5 This rewiring of the brain and restoration of function can be helped with therapy, and this is the goal of CIMT.

In one study of CIMT, researchers used focal transcranial magnetic stimulation to map the area of the brain that normally controlled arm movement on the weakened side of the body in 13 stroke survivors. They found that after 12 days of CIMT, not only was use returning to the arm, but the mapped area of the brain had nearly doubled in size. The improvement in motor performance and the increase in brain size lasted at least through the study follow-up at six months.⁶

The study emphasized, though, that the therapy succeeded only if patients worked at it full time, and that only through intense use of the affected limb will the brain be sufficiently rewired. Indeed, one of the major differences between CIMT and conventional therapies is, essentially, intensity.⁷

The development of CIMT was initiated by research led by Edward Taub, who opened the Taub Therapy Clinic at the UAB Hospital in 2001. In 1993, Taub studied monkeys whose forelimbs were surgically deprived of sensation.^8,9 His research demonstrated that injury to the nervous system results in cortical reorganization, meaning the brain retrains good cells to do the work of damaged ones.

Taub proposed that after a stroke, some of the disability that patients experience may result in part from "learned non-use" of the affected limb. The theory behind CIMT is that impairment has a behavioral basis as well as a neurological one. What this means is that CIMT may be applied in other conditions in which impairment may be caused in part by learned non-use, such as cerebral palsy and spinal cord and hip injuries.^10,11

Ongoing studies to determine benefits

So far, CIMT has been used mainly in post-stroke patients with upper-extremity hemiparesis, or weakness, at the Taub Therapy Clinic and the Advanced Recovery Rehabilitation Center in Sherman Oaks, CA, among other facilities. To prevent use of the unaffected hand, these patients wear a mitt or other restraining device for 90% of their waking hours. The patient attends a six-hour therapy session, five days a week, for two to three weeks. During the session, a physical or occupational therapist works exclusively with the patient to practice a behavioral technique known as shaping.⁵ As the patient repeats timed exercises, the therapist acts as a coach, encouraging the patient to improve each task.

The different repetitive tasks are performed continuously for about 15 - 20 minutes. The tasks have functional relevance—eating, using a phone, buttoning a garment, and other everyday activities—and each task is broken down into small steps.

When learning to drink from a cup using the affected hand, for example, a patient might initially practice moving his hand toward the cup, with feedback from the therapist. The next set of activities might include grasping the cup, followed by grasping just the handle, then picking up the cup, picking up the cup filled with liquid, and finally drinking from the cup. Therapists record the patient's progress and may encourage home follow-up.

It's estimated that about half of the total stroke population may benefit from CIMT.¹² Early outcomes from experimental studies have shown promise, in that CIMT has helped some stroke survivors avoid or overcome nonuse and regain upper limb function, with improvement in objective measures of dexterity and motor function.^13,14 These studies involved patients who'd undergone CIMT therapy from six months to 17 years post-stroke.

Determining whether CIMT will be more effective in stroke patients who are retrained sooner—from three to six months after suffering a stroke—is the aim of the federally funded Extremity Constraint-Induced Therapy Evaluation (EXCITE), the first national clinical research trial of its kind.¹⁵ This five-year, $7.5 million study of 240 patients at seven academic medical centers is an important step toward determining the effectiveness of CIMT and whether it is superior to traditional therapies.¹⁶

Although CIMT is a promising treatment, it will not be appropriate for everyone. It's more time-consuming, more demanding, and much more expensive than conventional rehabilitation. The Advanced Recovery Rehabilitation Center, for example, offers a two-week CIMT program for the upper extremities, for six hours a day, five days a week, at a cost of $5,000, which is not usually covered by Medicare or private insurance. Ultimately, though, research will define the best method of delivering CIMT and the role that it will play in stroke rehabilitation. In the meantime, you can encourage your stroke patients to use their affected limbs and to bring up the possibility of CIMT with their primary care provider. Who knows? Sometime in the near future, constraint-induced movement therapy may be considered one of the more conventional approaches to stroke rehabilitation.

Web Exclusive

REFERENCES

1. National Institute of Neurological Disorders and Stroke. "Stroke: Hope through research." 2004. www.ninds.nih.gov/disorders/stroke/detail_stroke.htm (9 Nov. 2004).

2. National Institute of Neurological Disorders and Stroke. "Post-stroke rehabilitation fact sheet." 2003. www.ninds.nih.gov/health_and_medical/pubs/poststrokerehab.htm (3 Nov. 2004).

3. Roth, E. J., & Harvey, R. L. (2000). Rehabilitation of stroke syndromes. In R. L. Braddom, Physical medicine and rehabilitation (2nd ed.). Philadelphia: W. B. Saunders Co.

4. Barker, E. (2002). Neuroscience nursing: A spectrum of care (2nd ed.). St. Louis: Mosby.

5. UAB Health System. "Taub therapy: Why it works." 2004. www.taubtherapy.com/show.asp?durki=61465 (9 Nov. 2004).

6. Liepert, J., Bauder, H., et al. (2000). Treatment-induced cortical reorganization after stroke in humans. Stroke, 31(6), 1210.

7. Maltin, L. J. "Stroke victims exercise the body to exercise the mind." 2000. my.webmd.com/content/Article/25/1728_58141.htm (9 Nov. 2004).

8. Reuters Health. "Therapy can give chronic stroke patients reuse of affected limb." 2001. www.neurologychannel.com/NeurologyWorld/02212001_therapy.shtml (2 Nov. 2004).

9. Taub, E., Miller, N. E., et al. (1993). Techniques to improve chronic motor deficit after stroke. Arch Phys Med Rehabil, 74(4), 347.

10. Taub, E., Ramey, S., et al. (2004). Efficacy of constraint-induced movement therapy for children with cerebral palsy with asymmetric motor impairment. Pediatrics, 113(2), 305.

11. Jackson, N. M. "Stroke therapy hobbles one arm." 2003. www.healthatoz.com/healthatoz/Atoz/dc/caz/neur/stro/alert05062003.jsp (3 Nov. 2004).

12. Taub, E., Crago, J. E., & Uswatte, G. (1998). Constraint-induced movement therapy: A new approach to treatment in physical rehabilitation. Rehabil Psychol, 43(2), 152.

13. Aycock, D. M., Blanton, S., et al. (2004). What is constraint-induced therapy? Rehabil Nurs, 29(4), 114.

14. Dromerick, A. W., Edwards, D. F., & Han, M. (2000). Does the application of constraint-induced movement therapy during acute rehabilitation reduce arm impairment after ischemic stroke? Stroke, 31(12), 2984.

15. Cox News Service. "Forcing their hand: New approach to therapy could offer breakthrough to millions of stroke victims." 2001. www.intelihealth.com/IH/ihtIH/WSIHW000/8124/20792/332370.html (9 Nov. 2004).

16. Dromerick, A. W. "Evidence-based rehabilitation: The case for and against constraint-induced movement therapy." 2003. www.vard.org/jour/03/40/1/guested.html (3 Nov. 2004).

Stroke research today

The National Institute of Neurological Disorders and Stroke (NINDS), a component of the National Institutes of Health, sponsors a multitude of research on disorders of the brain and nervous system, including all phases of stroke. Current NINDS stroke research is focusing on the following:

Neuroprotection. Scientists are looking for ways to prevent secondary brain injury following the initial wave of brain cell death by providing neuroprotection to salvageable cells. Neuroprotection includes preventing inflammation and blocking some of the toxic chemicals created by the dying brain cells.

Vasodilators. Researchers are trying to determine whether these drugs can be used to increase blood flow to the brain. So far, studies have had limited success, possibly because the vasodilators were not given soon enough after the onset of stroke.

Brain plasticity. This research looks at how the brain adapts to injury by reorganizing its functions, using noninvasive imaging technologies to map patterns of biological activity inside the brain. Other studies are looking at brain reorganization after stroke to determine whether specific rehabilitative techniques, such as constraint-induced movement therapy (CIMT), can stimulate brain plasticity, thereby improving motor function and decreasing disability.

Implantation of neural stem cells. The objective of this research is to see whether these cells are able to replace the cells that have died as a result of a stroke.

Sources: 1. National Institute of Neurological Disorders and Stroke. "Post-stroke rehabilitation fact sheet." 2003. www.ninds.nih.gov/health_and_medical/pubs/poststrokerehab.htm (10 Nov. 2004). 2. National Institute of Neurological Disorders and Stroke. "Stroke: Hope through research." 2004. www.ninds.nih.gov/health_and_medical/pubs/stroke_hope_through_research.htm#Research (10 Nov. 2004).