Researchers at the Swiss Federal Institute of Technology Lausanne have developed a groundbreaking device that allows amputees to experience natural temperature sensations with their prostheses. The innovation opens the door to integrating a range of sensations into artificial limbs, enhancing the overall functionality and user experience.
The team, led by Prof Solaiman Shokur, recognized that sensory feedback is crucial for amputees to feel that their prosthetic limb is a part of their body. They understood that temperature plays a significant role in creating a natural sensation. Shokur explained, “To give a natural sensation, you cannot do it without temperature.” By replicating thermal sensations in an amputated hand, the researchers aimed to provide amputees with a more immersive and realistic experience.
The researchers developed a device called the MiniTouch, which consists of a temperature sensor placed on the prosthetic hand at the location where phantom thermal sensations typically arise. When the sensor detects a change in temperature, it sends a signal to a temperature controller. This information is then relayed to another component mounted on the upper part of the prosthesis, which touches the skin of the arm. The sensor’s detected temperature is reproduced on the arm at the trigger location for the phantom sensations.
In a study conducted by the team, the MiniTouch was fitted to the prosthesis of Fabrizio, a 57-year-old amputee. Fabrizio demonstrated remarkable accuracy in discriminating between bottles containing cold, hot, or room-temperature water when using the device. Without the device, his accuracy dropped significantly. Additionally, Fabrizio was able to distinguish between different materials, such as copper, glass, and plastic, with equal accuracy when blindfolded using the MiniTouch and his intact hand. However, without the device, his choices were based on chance.
The MiniTouch also improved Fabrizio’s ability to distinguish between real and prosthetic arms when blindfolded, although his intact hand still performed better, possibly due to the additional sensory information it receives. Furthermore, the device enhanced Fabrizio’s accuracy in sorting hot and cold steel cubes within a minute.
Fabrizio expressed his satisfaction with the device, stating that it provided him with a more intense phantom sensation in his missing hand when perceiving hot or cold objects. He compared it to his previous experience with a prosthetic hand that only offered basic movement, highlighting the significant advancements made possible by these new technologies.
The researchers emphasize that the MiniTouch does not require surgery and can be easily attached to existing prosthetics. It is also cost-effective and customizable, making it accessible to a larger group of patients. However, they acknowledge the need for further testing in a larger patient population.
Prof Silvestro Micera, another senior author of the study, revealed that the team’s future plans involve creating a single wearable system that can provide amputees with various sensations, including pressure, texture, position, temperature, and wetness. This integrated system would be a significant leap forward in enhancing the overall sensory experience for amputees.
Dr Sigrid Dupan, an expert in sensory feedback for prostheses at University College Dublin, praised the research as a significant advancement in thermal feedback for artificial limbs. However, she cautioned that not all amputees may experience phantom thermal sensations consistently, and more work is needed before these devices can be implemented widely in healthcare systems.
In conclusion, the development of the MiniTouch device represents a major breakthrough in enhancing the sensory experience for amputees. By replicating natural temperature sensations, researchers have taken a significant step towards creating more realistic and immersive prosthetic limbs. While further research is needed, the MiniTouch offers a promising solution that can be easily integrated into existing prosthetics, providing amputees with a greater sense of embodiment and functionality.
