Research Project Snapshot — Investigating Socket Sensation & Proprioception in Lower Limb Amputees

Prosthetic Sensation for Lower Limb Amputees Feature Image

Project Profile

Institution & Project Groups

Imperial College London, Neuromechanics and Rehabilitation Technology Group (Department of Bioengineering) and Human Performance Group (Department of Surgery & Cancer).

Project Description

The study is the biggest attempt of its kind to capture the experiences and perception of using a leg prosthesis in everyday life. Each person’s experience is unique, and this means there is a lot of diversity across the limb-difference population.

We want to build a picture of the needs of prosthetic users that can be used by engineers and clinicians to improve technology and rehabilitation programs so that they are more relevant and suited to what’s required.

This is part of a research project to develop prosthetic sockets that provide sensation and can communicate with lower limb prosthetics users.

Invitation to Participate

Would you like to help us develop advanced prosthetics that can provide sensation? Tell us about your experience with your prosthesis!

We are research engineers from Imperial College London and want to understand:

  • how amputees sense their prosthetic leg(s) and the ground through their sockets;
  • how this may affect your everyday experiences.

We are looking for volunteers over the age of 18, who have lower limb amputations and use a prosthetic foot, ankle or knee to take our anonymous online questionnaire (15-30 mins to complete).

At the end of the survey, you can register your interest to get involved with our future activities such as testing our prosthetic-sensation prototypes and providing your opinions and experiences (e.g. during focus groups).

The link is provided below and you can complete this on a smartphone, tablet or computer.

This study has received approval from the Imperial College Research Ethics board.

Here is the link for the Questionnaire and Participation Information Sheet: https://bitly.com/socketsense.

If you want to know more, please do not hesitate to contact Shloak Mehta by email at smm315@ic.ac.uk.

Many Thanks,

Shloak Mehta

Learn More About Socket Sensation and This Research

Why is sensation from the legs so important?

Walking and balancing is automatic – The central nervous system (brain+spine) can generate walking movements and make quick adjustments stabilise your body subconsciously, but this relies on information about the ground from your foot and knowing where your limbs are (without looking):

Controlling movements and reacting to the environment – our brain can plan movements and detect any disturbances from the environment. It can then react by comparing where it had planned for the limb to actually be during the movement to where it actually is and coordinate the muscles to adjust the movement and compensate for any external forces and slippery floor.

How might this affect amputees?

“You can only control what you sense” – Prof. Arthur Prochazka (Neuroscientist)

Prosthetic ankles and knees do not directly provide any sensory information to the central nervous system as a natural limb would do through nerve connections. This reduces the amount of information and therefore restricts the ability to sense the ground through the foot and limb movement.

The Body’s Ability to Develop a New Sense — Socket Sense

This socket is the only link between the body and the prosthetic, and the brain can incorporate sensory feedback from the pressure exerted on the residual limb through the socket. The skin under the socket of the residual limb becomes more sensitive and attuned to pressure stimuli over time. Amputees may be able to use this feedback to identify the type of surface they are walking on, whether it is flat/uneven/sloped, etc. It might even lead to a form of proprioception, i.e. the ability of the brain to sense the position of a limb in space.

Understanding the Problem and What We Are Doing About It

The quality of this socket sense varies widely between amputees and may depend on many factors such as skin sensitivity, experience and socket type. Also its ability to compensate for the original loss of sensory feedback is not well understood, but this loss and potentially limited recovery of sensation is one of the reasons behind many common issues such as:

  • high risk of falls and reduced balance;
  • reliance on visual guidance;
  • low balance confidence and fear of falling;
  • more concentration needed to walk;
  • gait abnormalities which can lead to long term damage to joints;
  • long learning curve with prosthetics during rehabilitation.

The first step in the research process is therefore to study current user experiences to understand what influences the quality of sensory feedback from the socket, who is more at risk of low-quality feedback, and how this might affect the daily lives of users.

Understanding the development of socket sensation may allow better rehabilitation practices to focus on developing this sense, and guide efforts to provide additional artificial sensation. These efforts will integrate sensation into modern prosthetics so that the issues above can be tackled to improve the experience, performance and quality of life for amputees.

Prosthetic legs development including microcontroller, powered and mind-controlled prosthetics is a big research field, which is advancing all the time with more functionality and active range of motion. But, improving sensory feedback will be just as important, otherwise, these will more complex prosthetics will be much more difficult to use. There are many research projects across the world focused on this problem too, so it is an exciting time.

If you are a lower-limb amputee, you can participate first by filling out the survey above. Following this, you can register to get further involved in the project, like testing our prototypes!

Related Information

For more information on sensory feedback for bionic lower limbs, please see Understanding Bionic Touch and Sensory Feedback for Bionic Feet.

For a comprehensive description of all current lower-limb technologies, devices, and research, see Complete Guide to Bionic Legs & Feet.

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