Why Do Passive Motion Devices Not Heal The Brain?

With Dr. Nick Housley 16th Nov, 21


A stroke rehabilitation program may use active and passive motion devices. Passive motion devices assist you in increasing your range of motion without engaging your muscles. However, active motion devices can heal the brain of stroke survivors because they need muscle engagement.

Why Do Active Motion Devices Work Better?

In physical/outpatient therapy, you do 30-40 repetitions per hour on average to strengthen or reduce spasticity or improve the precision of your movements. However, robotic devices can help you do this therapy from your home.

Also, you can do 300-400 repetitions an hour on average with the help of these active motion devices. It means a lot more movement than your typical sessions to rewire your brain to increase motion.

Why Do Outpatient Settings Not Improve Brain Function?

To improve brain function, you have to perform 400-600 repetitions a day, which is a lot of movement. In contrast, in most outpatient therapy settings, you see your therapist for 45-60 minutes 2-3 times a week, and you do between 30-40 repetitions. It is about tenfold what is actually needed. As a result, this stroke rehabilitation is insufficient to improve brain function.

Why Do Passive Motion Devices Not Rewire Your Brain?

For your brain to rewire, it is not sufficient for you to have movements imposed upon you. You have to be actively engaged in those motions for your brain to respond.

In the past, continuous passive motion (CPM) devices helped increase range of motion, reduce DVT, and improve blood circulation for stroke patients. But it does not have that much influence on reducing the relative risk of DVT and no added benefits. Those devices may be effective in helping reduce pain or making you feel good, but if the goal is to improve function, you need to be actively engaged in it.

Additionally, it does not mean you can do something in a challenging situation or independently just because you can have something imposed upon you. For instance, when you sit in front of a piano that plays itself. It will look like you are playing that piano, but it will not happen if you put yourself in front of a piano that does not play itself.

How Does Motus Hand/Foot Help In Rewiring The Brain?

Motus Nova devices are active motion devices. Motus Nova aims to help people regain as much independence as possible without requiring help. Motus Nova can move just like any other CPM device, but it does not operate similarly. It functions under the input of a stroke or neurologic injury survivor. Therefore, it can enhance movements and either amplify or help to initiate them and complete them. But it will not necessarily do that for you without being actively engaged.

The Motus Hand and Foot have fine sensors that can attack small movements such as one-degree movements, detect those movements and then amplify them because it checks every couple of milliseconds. The system works with a combination of the forces your body produces and the range of motion with the intention of moving and accelerating movements. The active motion devices operate as a hybrid between you and your brain to amplify your activities.


Therapists use passive motion devices to help you improve mobility and range of motion, but those devices do not require your involvement or muscle engagement. By contrast, active motion devices such as the Motus hand/foot help you regain motor control by stimulating your brain.

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