In Dr. Norman Doidge’s book, How the Brain Changes Itself, the author summarizes a study that led to Constraint-Induced Therapy (CIT) for stroke survivors.
The study was done by Edward Taub and involved the deafferentation (cutting sensory nerves, but leaving the motor nerves) of monkeys’ arms, which resulted in the inability to use the arm. Deafferent a left arm, and the monkey cannot move the left arm; same for the right. Deafferent both arms, though, and the monkey is able to use both.
According to Doidge, “[Taub] reasoned that if both arms were deafferented, a monkey should soon be able to use them both, because it would have to to survive.”
That conclusion meant that stroke survivors should be forced to use their affected side, because if they needed to use it, they would. One story told by a stroke survivor was that one morning in rehab, she asked for coffee, and her therapist put an oven mitt on the patient’s unaffected hand (to constrain it), pointed to a coffeemaker, and said, “You’ll have to make it yourself.” Because the oven mitt made her functioning hand unable to use the coffeemaker, the patient used her affected hand. Because she had no other choice.
I say, “Nonsense,” because after having a stroke, I would have had to go without coffee; there was no way of getting my useless hand to use a coffeemaker – no matter how much I needed/wanted that coffee. Maybe the stroke survivor had partial use of her hand, which made the technique work.
On the other hand, I had no control whatsoever over the muscles on the affected half of my body. In fact, I can show exactly how the monkey-study did not apply to me – in rehab, I wanted badly to sit on the edge of my bed (I’m not sure why it was so important to me); whenever I tried, though, I could swing my unaffected leg over, but when I pushed myself up to sit, I promptly fell to my left – sometimes landing on the bed and sometimes off. Certainly when I fell off the bed I needed my left side to catch me, but it didn’t step up as required.
In general, CIT is used as therapy for the upper limb (arm/hand) rather than the lower (leg) because there are fewer safe one-legged activities: if I make the unaffected leg unusable, there’s nothing absolutely required for survival for the affected leg to do by itself.
On the other hand, in my life, the use of my unaffected leg has been hampered by arthritis and bone spurs. Make my unaffected leg unusable, and my affected leg will be required to step up and take the lead.
That’s the plan starting this Friday, when my “good” leg will be disabled by surgery. It will be, as stroke survivor Grace Carpenter recognized, CIT for my other leg. I will be forced to use my affected leg for nearly everything, whether it likes it or not. The 6 years since the stroke has enabled this: Immediately after the stroke, my left (affected) leg would not have been able to do this, but I’ve just spent 6 years regaining control of and strengthening the leg so that it will be capable of doing so. It must.
And if my hand had made just as much progress as my leg in the past 6 years, you can bet I’d be trying CIT on my hand too.
See the original article: