Making Arms Weightless
The client has cerebral palsy and uses a motorised wheelchair. She does not have sufficient strength in her arms to lift them, let alone to lift a cup, so she is completely dependent on other people for eating and drinking.
This solution, which was partly inspired by a previous REMAP project, https://remap.org.uk/solutions/making-arms-weightless/, uses counterweights to balance the weight of her arms. It is attached to her motorised wheelchair and can be easily folded out of the way when not being used.
The Challenge
The client has cerebral palsy and lacks the strength even to lift her arms. This means that she is completely dependent on help to eat and drink and cannot undertake exercise to increase the muscle strength in her arms.
She has tried a sophisticated robotic arm which should respond to her attempts to move, but did not find it effective. Her OT was therefore not optimistic about a lower-tech solution but was persuaded by previous case https://remap.org.uk/solutions/making-arms-weightless/ that it was worth trying.
The solution
The solution uses 25mm steel scrap offcuts in drawstring bags as counterweights, which are connected via a tubular jib and pulley system to fleece loops around the client’s wrists or lower arms. The amount of steel in the bags can be adjusted to exactly counterbalance the weight of her arms, so that she can move them up and down more easily.
The mechanism slots into a socket connected to the back of her motorised wheelchair and can easily be folded out of the way or removed completely when not in use.
The tubes were scavenged from a discarded clothes rail. 3D printed parts allowed the four pulley wheels to be mounted in an offset arrangement so that two cords, one per arm, could run from a single jib. The side plates of the hinge were made from surplus laminate flooring boards.
The benefit
Before making the final equipment we tried a lash-up to test whether it would be effective. The client was clearly delighted: she spent the whole time moving her arms up and down and was reluctant to let us take it away. The final solution had a similar effect when that was delivered. She loves it, and so uses it willingly and regularly; within days she was able to do activities, such as art, that she hadn’t been able to do for years.
The client does not yet have the strength to lift a cup, even with the help of this device, but, because she is now able to move her arms, she can now exercise them more effectively in order to build up muscle strength. With this incorporated into her regime, her physiotherapist is confident that she will eventually have the strength to do much more unaided.
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