Inside Your Toolbox: Constraint-Induced Movement Therapy


A stroke can happen to anyone at any time, regardless of race, sex, or age. The effects can range between mild to devastating depending on factors such as location and amount of brain tissue affected. Some problems encountered include: one-sided weakness or paralysis, speech difficulties, and issues with cognition – among other things. One thing is certain - these can carry major quality of life ramifications that patients often struggle to deal with. Physical therapy is an integral part of the recovery process for these individuals, with emphasis placed on improving their overall functionality and independence. Let’s take a look at constraint-induced movement therapy (CIMT) as a treatment option to be considered.

What is Constraint-Induced Movement Therapy?

CIMT is a form of massed practice wherein the less affected upper extremity is restrained in order to impose increased use of the more affected extremity in the performance of motor tasks. This type of treatment can be used with patients diagnosed with stroke, spinal cord injury, cerebral palsy, and focal dystonia. 

The unique story behind this concept came from a woman who fell while sustaining a right CVA - simultaneously causing a fracture to her right humerus. Surprisingly enough, she significantly recovered the use of her left arm (side affected by the stroke) over a one year period. It is an interesting story and is essentially how CIMT is conducted. Let's take a look at the details. In general, there are three main factors:

  • The less affected arm is restrained for a 2-3 week period (typically a lightweight fiberglass cast, mitten, hand splint, and a sling).
  • The more affected arm is intensely trained - with high repetition and performance of novel and functional tasks.
  • The therapy sessions is administered 6 hours a day for 2-3 weeks while allowing rest when needed.

Along with these factors, the patient should likely exhibit a certain level of baseline functioning prior to participation ---

An important criterion for receiving CIMT or modified CIMT is the ability to extend one or more fingers of the affected limb, suggesting that these therapy forms are restricted to patients with a mild to moderate paresis of the limb.
— Ching-Yi Wu et al. (2015)

How does CIMT work?

So, what is going on with CIMT? What adaptations are happening in the brain to allow for improvement? Isn’t the damage already done? All excellent questions. Here are the proposed training effects of CIMT:

  • Expansion of the contralateral cortical area responsible for controlling movement of the affected limb and recruitment of new ipsilateral regions.
  • Enhanced neuronal excitability in the damaged hemisphere.
  • Enlarging of motor cortex representations of an affected body part.
  • Functional remodeling of the intact adjacent tissue in the motor cortex.

If correct, the mechanism through which CIMT works would seem to be through adaptations within the brain - factors such as cortical reorganization and neural plasticity.

Is CIMT a practical treatment approach?

The protocol dictated by CIMT is not always reasonable for patients. Not everyone will be capable of handling the intense scheduling and amount of restraint necessary to perform this type of training. Additionally, there are numerous safety concerns with restraining an already impaired individual and having them perform mobility tasks. It is up to the clinician to utilize their clinical judgement and adjust to their patient accordingly. For example, here is a table that outlines various considerations and benefits when applying CIMT to a patient following a stroke:

Stages of Stroke Benefits Considerations
Acute
(<4wks)
• May minimize non-use
• Prevents shrinking of cortical representation areas
• Improves motor function w/o increasing treatment time
• Improvements in UE reach tests but none in ADLs
• Safety concerns due to possible compromised balance and mental function
• Painful overuse syndrome and frustration of using weak and clumsy limb
• Possible lesion enlargement due to glutamate excitotoxicity or induced hyperthermia
Subacute
(4wks-1 year)
• Improvement in the patient's performance • Spontaneous recovery is known to occur during this stage
Chronic
(>1 year)
• Current studies demonstrate that CIMT is a powerful treatment for improving function in chronic stroke patients • Must revisit traditional rehabilitative and compensatory views in chronic stroke patients

There is also a modified version of CIMT available that may be more manageable for patients. Page et al utilized this protocol and was able to produce favorable results:

  • 30 minute functional practice sessions occurring 3 days/week
  • Restriction of the less affected arm 5 days/week for 5 hours
  • Administered for a 10-week period

Does CIMT work? Is it superior to traditional rehabilitation methods?

According to the research, there are mixed results. One very recent meta-analysis by Corbetta et al. stated that CIMT was associated with small improvements in motor impairment and function, but that these benefits did not convincingly reduce disability. Here are their findings:

  • "Eleven studies (with 344 participants) assessed the effect of CIMT on disability (the effective use of the arm in daily living) and found that the use of CIMT did not lead to improvement in ability to manage everyday activities such as bathing, dressing, eating, and toileting."                           
  • "Twenty-eight trials (with 858 participants) tested whether CIMT improved the ability to use the affected arm. CIMT appeared to be more effective at improving arm movement than active physiotherapy treatments or no treatment."

Not too convincing. Given the varying results of the literature, it is difficult to come to a conclusion on CIMT - at least when comparing it to traditional methods. Further research may be necessary to determine its usefulness and placement in the rehabilitation process. What are your thoughts on this treatment strategy? Have you used this in the clinic before and if so, what were the results?