Monday, January 14, 2013

Mirror Therapy Stroke Recovery

Find video of mirror therapy at the end of this article
Most recovery from stroke requires neuroplastic "rewiring" of the brain. Forging neuroplastic change in the cortex, the outer shell of the brain where much of neuroplastic action takes place, involves an incredible amount of effort on the part of the stroke survivor. 

It also takes time and resources dedicated to that effort. There are, however, recovery options that stroke survivors can use that to not burn through a lot of resources.  These recovery options can be added as a simple and effective adjunct to traditional therapy.

One example of such a recovery option is mirror therapy. Much research remains to be done to fully prove efficacy of mirror therapy. But for some stroke survivors mirror therapy appears to be a promising and effective option for reestablishing cortical control over wayward limbs.

Mirror therapy
· requires very little training 
· survivors with very little movement can   do it 
· is easy to set up 
· is not taxing to the patient

Mirror therapy for the upper extremity.
The stroke survivor is seated. A mirror is aligned to intersect with the patient's body in the sagittal plane at chest level. This is usually done by placing the mirror on a table with the hands resting on the table on either side of the mirror. The reflective part of the mirror faces the unaffected side. As the patient looks into the mirror, all they see is the unaffected side. The mirror blocks the view of the unaffected side of the body. The patient gazes into the mirror reflecting the "good" hand. When the "good" hand is moved the mirror gives the illusion that the "bad" hand is moving perfectly well.
Often, a "mirror box"—usually about twice the size of a shoebox—is used.  On one outside surface of the box is a mirror, which faces the unaffected side. The patient places the affected hand in the box so it is covered on all sides. The stroke survivor attempts to copy the movement of the “good” arm and hand with the hemiparetic arm. In other words, the movements are done symmetrically, like conducting an orchestra. However, the stroke survivor only sees the reflection of the good hand.

Mirror therapy for the lower extremity.
The stroke survivor can be either in long sitting on a plinth or seated on a chair. The advantage of the plinth is that the lower extremity is more easily viewed. The advantage of the chair is that it may be more comfortable for some patients. In either case, a mirror is placed the between the patient's legs to intersect patient's body in the sagittal plane. As with the upper extremity, the mirror is facing the unaffected side. The patient is instructed to plantar and dorsiflex the unaffected side ankle, and at the same time attempting to do the same movement with the unaffected side. The speed of the movement is self-selected.

For both the upper and lower extremity the dosage is 30 minutes a day, five days a week for four weeks.

How and why does it work?
There are two explanations for why mirror therapy seems to show efficacy in clinical research. The first is technical. The second explanation is better suited for patients who are less interested in the science and more interested in efficacy.
The scientific basis seems to be in what is activated when we are presented with the illusion of seeing both limbs when, in reality, we are only seeing one. Transcranial magnetic stimulation studies with mirror therapy reveal something remarkable; when the left hand is moving the left motor cortex is excited, and vice versa. Normally, of course, when the left hand moves, the motor cortex on the right side is activated. So if the stroke survivor has right-sided hemiparesis, viewing the "false” right hand in the mirror will activate the portion of the brain that controls the hemiparetic hand. If the stroke survivor is trying to activate the motor cortex for the affected side limb, research suggests that mirror therapy can be used to initiate that activation.

The simple explanation. But just like any other neuroplasticity-driving treatment option, it is primarily through the effort of the stroke survivor that rewiring takes place. For that reason it is essential that stroke survivors are educated on what works and how it works. Stroke survivors need to know why they're doing what they're doing in order to have them on board for the process. The challenge of making things scientifically accurate and easy-to-understand is essential to any patient education. Mirror therapy is no exception. The following can be used to describe the essence of mirror therapy to patients considering this option:
· The reflection of the good arm superimposes normal sensory signals on the brain.
· Mirror therapy provides proper visual input because the reflection helps them think that their affected arm is moving correctly.
· The reflection, perceived to be accurate movement is thought to reorganize the way the brain is wired.
· This fooling of the brain stimulates the brain to help with control of limb movement.

Here is a vid that will give you a general idea of how it works. I would suggest that the skill this therapist is suggesting (handwriting) may not be the best for this patient for 2 reasons:
1. Handwriting is a skill usually only done by the dominant hand. This patient cannot adequately perform handwriting with his non-dominant hand. So his left hand may not be the best teacher. This patient would probably be better served by working on something that the left hand can do flawlessly and that the right hand can learn from.
2. What movement should be chosen? I would suggest working on whatever movement the "bad" hand is on the cusp of doing. So if the survivor is on the cusp of opening the hand, work on that. Simple, basic movements seem to work best.


Carmen Lahiff-Jenkins said...

We have just posted about our new Rehabilitation edition for the World Stroke Organizations flagship journal International Journal of Stroke - you can access free articles about stroke rehabilitation here :)
We don't have anything on mirror therapy however we do have some similar therapies developed by Australian Dr Leeanne Carey an incredible OT with some amazing sensory therapies.

oc1dean said...

I'll be difficult, Is mirror therapy better than action observation?

Peter G Levine said...

Dean, better late than never: I don't know!

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