The Role of Able-Bodied Participants in Prosthetic Research

At Marins Med, our mission is to advance upper limb prosthetics by creating devices that not only restore functionality but also seamlessly integrate into the daily lives of amputees. A significant challenge in prosthetic rehabilitation is the learning curve associated with using body-powered prostheses, especially those that operate in a Voluntary Opening (VO) manner. However, our innovative ProHensor device is designed to overcome these challenges by aligning more naturally with human grip mechanics, thereby simplifying the training process and promoting higher prosthetic acceptance.

The Common Research Approach: Using Able-Bodied Participants

In the realm of prosthetic research, it's commonplace to enlist able-bodied individuals as test subjects to simulate prosthetic use. Studies like Huinink et al. (2016) have provided valuable insights into how different training protocols affect the functionality and kinematics of body-powered prostheses. Their research, titled “Learning to use a body-powered prosthesis: changes in functionality and kinematics”, involved 30 able-bodied participants who underwent various training regimens to assess improvements in prosthetic use.

While this approach offers practical advantages—such as easier recruitment and controlled environments—it also introduces certain limitations:

 

1. Differences in Motor Control: Able-bodied participants have intact limb      proprioception and motor control, which can influence how they adapt to and operate prosthetic devices compared to amputees who must integrate the prosthesis into their residual limb function.
2. Psychological Factors: The emotional and psychological aspects of limb loss, such as  grief and identity reconstruction, play a crucial role in prosthetic acceptance and sustained use. These factors are absent in able-bodied participants, potentially skewing the outcomes of such studies.
3. Real-World Application: The day-to-day challenges faced by amputees—ranging from navigating different terrains to performing complex tasks—are not fully      replicated in controlled study environments with able-bodied individuals.

 

Should This Matter?

Absolutely. While using able-bodied participants can provide initial data and help in the development of prosthetic mechanisms, it's essential to recognize that amputees are the ultimate end-users. Their unique experiences and challenges must be considered to ensure that prosthetic devices are both functional and comfortable in real-world settings. Ignoring these differences can lead to overgeneralized findings that may not translate effectively to the target population.

The Best-Case Scenario: Integrating Diverse Participants

The optimal research pathway integrates both simulation studies with able-bodied participants and direct studies with amputees. This mixed-methods approach allows researchers to:

Leverage the Advantages of Both Groups:

 

•      Able-Bodied Participants: Facilitate initial testing, hypothesis generation, and
      prototype development.
•      Amputees: Provide insights into real-world use, uncover unique challenges, and
      validate findings from simulation studies.

 

Enhance Validity and Reliability:

 

•      Cross-validate data from different participant groups to ensure that findings are robust and widely applicable.

 

Iterate Design Based on Comprehensive Feedback:

 

•      Use feedback from amputee studies to refine prosthetic designs, ensuring they meet the nuanced needs of end-users.

 

How ProHensor Bridges the Gap

Recognizing the limitations of traditional research approaches, Marins Med has developed the ProHensor, a Voluntary Closing (VC) and Locking body-powered terminal device. Here's how ProHensor addresses the challenges highlighted by research:

1. Natural Grip Alignment:

Intuitive Operation: Unlike VO devices that require users to perform counter-intuitive actions to open the prosthesis, ProHensor operates on a Voluntary Closing and Locking (VC&L)mechanism. This aligns closely with the natural action of closing a hand to grasp objects, reducing the cognitive load during training.

2. Locking Mechanism:

Effortless Hold: ProHensor features a self-actuating locking mechanism that allows the prosthesis to maintain a hold on objects without requiring continuous physical or mental effort from the user. This innovation minimizes fatigue, enabling users to perform tasks more efficiently and comfortably over extended periods.

3. Simplified Integration:

No Intensive Training Required:Due to its intuitive design, ProHensor does not necessitate the same level of intensive training as VO devices. Users can achieve functional proficiency more quickly, fostering greater prosthetic acceptance and sustained use without the need for a specialized training protocol.

An Analogy: Driving a Car

Imagine learning to drive a manual transmission car versus an automatic transmission car. A manual car requires the driver to engage in counter-intuitive actions like coordinating the clutch and shifting gears manually, which can be overwhelming for beginners. In contrast, an automatic car aligns with the natural expectation of shifting gears seamlessly, allowing the driver to focus more on the road and less on the mechanics of driving.

Similarly, VO prosthetic devices demand users to perform non-intuitive actions to open the prosthesis, akin to the manual clutch operation, which can be mentally taxing and physically demanding. On the other hand, ProHensor's VC & L (voluntary closing and locking) mechanism operates in a way that feels more natural and intuitive, much like an automatic transmission, enabling users to focus on performing tasks rather than struggling with device mechanics.

Promoting Prosthetic Acceptance

Effective integration of prosthetic devices is pivotal in fostering prosthetic acceptance. Devices that align closely with natural movement patterns and reduce the need for specialized training are more likely to be embraced by users, reducing rejection rates. By leveraging the insights from Huinink et al.’s research and enhancing them with our intuitive design, Marins Med is committed to developing prosthetic solutions that cater to the real-world needs of amputees.

Conclusion

While the use of able-bodied participants in prosthetic research provides valuable initial data, it's crucial to integrate insights from amputee studies to develop truly user-centric devices. ProHensor exemplifies this integration by offering an intuitive, efficient, and user-friendly prosthetic solution that minimizes the learning curve and maximizes prosthetic acceptance. At Marins Med, we are dedicated to bridging the gap between research and real-world application, ensuring that our prosthetic innovations meet the diverse needs of our users.

For more information on ProHensor and how it can transform your prosthetic experience, contact us today and embark on a journey towards enhanced independence and quality of life.