Todd Kuiken: A prosthetic arm that "feels"

Introduction to Bionics and Arm Amputations

In this section, the speaker introduces the concept of bionics and discusses how it is evolving for people with arm amputations.

Bionics and its Impact on Arm Amputations

• Bionics refers to the science of replacing part of a living organism with a mechatronic device or robot.

• Arm amputation causes functional impairment, emotional impact, and social barriers.

• Trauma, industrial accidents, motor vehicle collisions, and congenital limb deficiency are common causes of arm amputation.

• Current upper-limb prosthetics include body-powered prostheses and myoelectric prostheses.

Body-Powered Prostheses

• Body-powered prostheses use shoulder power to operate a hand or hook through a bicycle cable mechanism.

• These devices have been in use since the early 1900s and are still commonly used due to their simplicity and robustness.

Myoelectric Prostheses

• Myoelectric prostheses are motorized devices controlled by electrical signals from muscle contractions.

• They work well for individuals who have recently lost their hand as the muscles can still generate signals for control.

Challenges with Higher Levels of Amputation

• Individuals with higher levels of amputation face challenges in controlling robotic limbs using only their remaining arm muscles.

• Existing robotic arms in the market offer limited functionality such as hand opening/closing, wrist rotation, and elbow movement.

Neural Interface for Robotic Arms Control

This section focuses on the need for a neural interface to control robotic arms effectively.

Neural Interface Challenges

• Traditional approaches involve recording signals directly from individual neurons in the brain or peripheral nerves. However, these methods are complex and not suitable for current patients.

• The speaker introduces a different approach called targeted reinnervation, which involves using muscles as a biological amplifier to amplify nerve signals.

Targeted Reinnervation

• Targeted reinnervation involves redirecting major nerves from the chest muscle to allow them to grow into it.

• By thinking specific commands, such as "close hand" or "bend elbow," the corresponding sections of the chest muscle contract and generate detectable electrical signals.

• These signals can be picked up by electrodes or antennae and used to control the movement of robotic arms.

Case Study: Jesse Sullivan

This section presents a case study of Jesse Sullivan, who lost both his arms in an accident and underwent targeted reinnervation.

Jesse Sullivan's Story

• Jesse Sullivan was a lineman who suffered severe burns that led to the amputation of both his arms at the shoulder.

• He underwent targeted reinnervation at the Rehab Institute of Chicago (RIC).

• Through targeted reinnervation, Jesse regained some control over robotic arms by using his chest muscle contractions as command signals.

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New Section

In this section, Dr. Todd Kuiken discusses targeted reinnervation surgery and its impact on prosthetic control and sensation.

Targeted Reinnervation Surgery

• Dr. Greg Dumanian performed the targeted reinnervation surgery on Jesse, a patient who required revision surgery on his chest.

• The surgery involved cutting away the nerve to Jesse's own muscle and shifting the arm nerves onto his chest.

• After three months, the nerves grew in and twitching was observed. After six months, strong contractions were visible.

• This surgical technique allows for intuitive control of the prosthetic limb based on the patient's thoughts.

Prosthetic Control and Sensation

• When Jesse thinks about opening or closing his hand or bending or straightening his elbow, movements can be seen on his chest where electrodes are placed.

• This intuitive control does not require a learning process.

• Jesse demonstrated improved performance with a targeted reinnervation prosthesis compared to his original prosthesis.

• Only three signals are currently being utilized, but there is potential for further improvement.

New Section

Dr. Todd Kuiken shares an unexpected discovery related to sensory feedback after targeted reinnervation surgery.

Sensory Feedback Restoration

• Touching Jesse's chest after the surgery resulted in him feeling sensations in his missing hand.

• The sensation extended to different areas of his hand depending on where it was touched.

• He could feel light touch down to one gram of force and differentiate between hot, cold, sharp, and dull sensations.

• This exciting development opens up possibilities for providing sensory feedback through sensors in the prosthetic hand.

New Section

Dr. Todd Kuiken discusses the application of targeted reinnervation surgery in patients with above-the-elbow amputations.

Application in Above-the-Elbow Amputations

• Nerve transfers are performed on patients with above-the-elbow amputations, allowing for up-down and hand open-close signals.

• Improved performance and intuitive control were observed in patients like Chris who underwent targeted reinnervation surgery.

• The goal is to enable simultaneous and intuitive use of the elbow and hand.

New Section

Dr. Todd Kuiken introduces Amanda Kitts, a patient who underwent targeted reinnervation surgery, to share her experience.

Patient Testimonial: Amanda Kitts

• Amanda lost her arm in a car accident in 2006.

• Prior to targeted reinnervation surgery, she had difficulty using a conventional prosthetic arm due to limited muscle control.

• After the surgery, she was able to use her elbow and hand simultaneously through thought control.

• The new prosthesis provided faster and more natural movement.

New Section

Dr. Todd Kuiken highlights the success of targeted reinnervation surgery and its impact on patients worldwide.

Success of Targeted Reinnervation Surgery

• Over 50 patients worldwide have undergone targeted reinnervation surgery, including wounded warriors from the U.S. armed services.

• The success rate of nerve transfers is high at approximately 96% due to the connection between large nerves and small muscle segments.

• Functional testing shows improved speed and ease of use with intuitive control.

• Patients have expressed appreciation for the benefits provided by this surgical technique.

New Section

Dr. Todd Kuiken expresses the desire to further improve targeted reinnervation surgery.

Future Improvements

• The goal is to continue advancing and refining targeted reinnervation surgery.

• Further research and development are needed to enhance prosthetic control and sensory feedback.

• Dr. Todd Kuiken and his team aim to provide even better outcomes for patients in the future.

New Section

In this section, the speaker discusses how they recorded data from various movements and used pattern recognition algorithms to control a research arm.

Recording and Analyzing Movements

• The speaker's team recorded data from different movements, ranging from wiggling a finger to moving a whole arm.

• They used pattern recognition algorithms similar to speech recognition algorithms to analyze the recorded data.

• By analyzing the data, they were able to identify different patterns corresponding to different movements.

New Section

In this section, the speaker explains how they collaborated with colleagues to develop an algorithm for controlling the research arm.

Algorithm Control for Arm Movements

• The speaker's team collaborated with colleagues at the University of New Brunswick to develop an algorithm control system.

• This algorithm allows users to control specific movements of the arm, such as elbow movement, wrist rotation, wrist flexion and extension, and hand open/close.

• The algorithm is trained using individual muscle signals from the user.

New Section

In this section, the speaker discusses the weight of the research arm and its control mechanism.

Weight and Control of the Research Arm

• The research arm is made up of commercial components and weighs about seven pounds.

• Amanda, who demonstrates using the arm, carries its weight through harnesses since it's not directly attached.

• The focus is not only on mechatronics but also on developing effective control mechanisms for seamless operation.

New Section

In this section, the speaker talks about a microcomputer that controls the research arm based on individual muscle signals.

Microcomputer Control System

• A small microcomputer operates behind Amanda's back and controls all functions of the research arm.

• Amanda trains the microcomputer to respond to her individual muscle signals.

• Initially, it took a few hours to train the arm using a computer, but now it can be trained with a small piece attached to the back.

New Section

In this section, the speaker discusses their goal of developing a clinically practical device and demonstrates advanced arms used by Amanda.

Clinically Practical Device

• The speaker's team aims to develop a clinically pragmatic device that can be worn comfortably.

• Amanda has also used more advanced arms developed by DEKA Research Corporation, showcasing good control and pattern recognition capabilities.

• These advanced arms offer multiple hand grasps based on user input.

New Section

In this section, the speaker discusses different hand grasp patterns and Amanda's experience using the DEKA arm.

Hand Grasp Patterns

• Users can select different hand grasp patterns by thinking about what they want while having an open hand.

• The DEKA arm allows for up to five or six different hand grasps.

• Amanda was able to perform four different hand grasps with the DEKA arm, including key grip, chuck grip, power grasp, and fine pinch.

New Section

In this section, the speaker shares Claudia's experience of feeling sensation through her prosthetic and highlights challenges related to electrode placement.

Sensation Feedback

• Claudia had a sensor at the end of her prosthesis that allowed her to feel different textures when rubbed over surfaces.

• This experiment aimed at giving back some skin sensation through prosthetics.

• Challenges arise in electrode placement due to interference from motors and other components.

New Section

In this section, the speaker discusses future goals related to improving signal quality and developing smaller and smarter prosthetic arms.

Future Goals

• The speaker's team aims to develop smaller capsules that can be placed in muscles to improve signal quality and eliminate electrode contact issues.

• They want to build a smaller, lighter, and smarter arm starting with the 25th percentile female size.

• The ultimate goal is to create a range of prosthetic arms that are practical, efficient, and customizable.

New Section

In this section, the speaker concludes by expressing excitement about future possibilities and acknowledging the challenges ahead.

Conclusion

• The speaker expresses enthusiasm for the future of prosthetics and their potential impact on improving lives.

• They appreciate the audience's presence and support in their journey.

• While there are challenges to overcome, such as electrode placement and noise interference, they remain optimistic about advancements in mechatronics and sensory feedback.