The need for intuitive upper arm bionics
Around 5,500 adults and children in the UK are living with an upper limb amputation or have congenital upper limb deficiency and hundreds more amputation procedures take place every year.
According to the MOD, in Afghanistan 240 British servicemen suffered amputations after being wounded between 2007 and 2013
Since that time many more serving and ex-military personnel have lost limbs through complications, or in other conflicts and accidents within the armed forces.
The most common causes of upper limb loss are congenital birth conditions or surgical removal due to injury, disease or vascular reasons (poor blood flow).
Upper limb amputation is functionally more disabling than lower limb amputation because of the vast number of fine motor skills undertaken by the hand and arm.
Limb-loss is extremely traumatic for patients and their families. It can impact on a patient’s mental as well as physical health and affect their emotional wellbeing, independence, mobility and financial situation.
Current prosthetic solutions
There are a variety of bionic limbs available; however, the current technology has drawbacks that affect both wearability and functionality for the user.
- The functionality of even high-end upper limb bionic prosthetics is still extremely poor – they can be unreliable, impractical and difficult to use.
- Bionic limbs are currently attached onto the amputation stump with sockets, straps and harnesses. Depending on their mobility, it can be extremely difficult for the patient to put on a bionic limb by themselves
- The sockets, harnesses and bionic arm socket can all cause painful chafing, which can lead to infection and ulcers
- Once fitted, the bionic limbs can be difficult to utilise, delivering very little practical benefit in terms of functionality
- Electrodes and wires are placed on the skin to transmit signals from the muscles to the prosthesis. However, these are only able to detect a limited number of signals, they restrict natural movement and often fall off due to sweat and movement
Bionic prosthetics – a future with functionality
RAFT wants to make upper arm prosthetics completely intuitive. We are undertaking research that will result in bionic prosthetics that fit perfectly and can be operated as intuitively as if it were the patient’s own hand and arm.
Our research is focusing on the development of pioneering technology that will enable existing and future upper limb bionics to work as effectively as the human arm.
A life without wires
Current bionics are operated using wires, which are placed on to the skin and transmit signals from the arm stump enabling the arm and hand to move.
However, these are only able to detect a limited number of clear signals so the prosthetic does not always function in the way desired, if at all. The wires also can restrict natural movement and often fall off as the wearer moves or due to sweat, making the bionic arm impractical to use.
In fact, studies in the US and UK indicate that more than 66% of amputees find usability and comfort such an issue that most only wear their prosthesis for up to two hours a day and a significant number give up using it altogether.
Eradicating wires for good
Our scientists in collaboration with University College London are working on the development of a micro electronic device that will be implanted under the skin on the amputation stump. This device will allow signals to be sent directly from the brain through the patient’s muscles directly to the bionic arm and back again.
The end result will be a prosthetic arm that works intuitively much like a human arm, is practical and affordable.
RAFT bionic Research Partner:
RAFT is collaborating with University College London (UCL) on this project.
The collaboration with UCL started in autumn 2016 and is scheduled for completion in spring 2018.