Challenging Standardized Testing in Prosthetic Research:

The field of prosthetics is driven by innovation, but when it comes to testing upper-limb terminal devices, the procedures in place have an inherent flaw. These tests, designed to measure the functionality and usability of prosthetic devices, often fail to consider the resourcefulness and adaptability of the amputees who use them.

Standardized testing assumes that a prosthetic device, such as a hand or hook, should perform tasks in the same way a biological hand would. But this assumption ignores the reality of how amputees live and adapt. Amputees, by necessity, are experts in modification. They continuously adjust and customize their terminal devices to fit their unique needs and preferences, optimizing outcomes in ways that no standardized test could predict.

At Marins Med, our CTO Darryl DuBre has experienced this firsthand, both as an amputee and as a prosthetic designer. “There is no one way to use a prosthetic,” DuBre says. “Testing procedures that assume there is a ‘correct’ way to perform a task with a prosthetic limb are missing the point. Every amputee has different ways of modifying to get the best result.”

Testing Assumptions vs. Amputee Ingenuity

The standardized tests used to evaluate upper-limb terminal devices focus on replicating the function of a biological hand. They measure how well a device can grasp, pinch, and manipulate objects, but they do so under rigid conditions, expecting amputees to perform tasks in a “natural” way—without allowing for the ingenuity that so many amputees employ in their daily lives. This approach limits the scope of what these devices can do and, ultimately, undermines their potential for success.

Amputees are often forced to get creative with their devices. These modifications are essential to their functionality and usability but testing protocols do not account for this adaptability. Instead, they force amputees into a box, measuring success by how closely they can replicate the movements of a biological hand, without considering that amputees may be achieving even better results through their unique adaptations.

The Flaws of Standardization in Prosthetic Testing

One key flaw in current testing procedures is that they do not allow for individual customization. When testing upper-limb terminal devices like the ProHensor (also known as the ProHook), researchers expect users to complete tasks as if they were using a human hand. This approach ignores the fact that prosthetic devices are not meant to be exact replicas of human limbs; they are tools designed to help amputees perform tasks in the way that works best for them.

The problem with these tests is that they overlook the creativity that amputees bring to the table. Every amputee has a different way of using their prosthetic device to achieve the desired outcome. For example, some might modify their terminal device for specific tasks like gripping tools or lifting objects, creating a highly personalized adaptation that a standardized test would consider "incorrect" simply because it deviates from the expected norm.

Darryl DuBre, with his deep understanding of both prosthetic design and the amputee experience, believes that these testing standards are limiting. “There is no one right way to use a prosthetic limb,” DuBre says. “Amputees shouldn’t be forced to mimic biological hands. They should be encouraged to innovate and adapt to meet their needs.”

Rejecting the Standard and Pushing Boundaries

At Marins Med, we are redefining how prosthetics are tested and used. Our focus is on creating devices that can be easily modified and adapted by the user to achieve the best outcomes. The ProHook, for instance, is designed with a self-actuated locking system that empowers users to take full control of their grip and hold. It’s a tool that responds to the user’s needs, not the other way around.

“The ProHook was created with the understanding that amputees are not trying to replicate a hand,” DuBre explains. “They are trying to perform tasks in a way that works best for them, using the tools they have available. Our goal is to give them the best tool possible.”

By rejecting the limitations of traditional testing, DuBre and Marins Med are pushing the boundaries of what’s possible in prosthetics. They believe that instead of focusing on how closely a prosthetic device mimics a hand, the emphasis should be on how effectively it helps the user accomplish their goals.

A New Way Forward

The future of prosthetics lies in embracing the creativity and ingenuity of amputees, not restricting them to outdated testing models. Devices like the ProHook are built with this in mind—offering not just functionality, but adaptability. The key to a successful prosthetic is not how well it can mimic a hand, but how well it can help the user navigate the challenges of their daily life.

At Marins Med, we are committed to developing prosthetic solutions that prioritize the user’s experience and their unique ways of using their device. By rejecting standardized testing norms and embracing a more flexible, user-driven approach, we are paving the way for a future where prosthetics are not just tools but personalized extensions of the people who use them.

If prosthetic research and development can evolve to recognize the inherent adaptability of amputees, the results will be more empowering, innovative devices that truly reflect the needs and potential of the people who wear them.