Today we are launching a new series of content: the VBRRII interviews. Every month, we will publish a Q&A with a prominent figure in the field of Rehabilitation Medicine. The first protagonist of this new series is Domenico Prattichizzo, a professor of Robotics, Pro Rector for technological transfer at the University of Siena, and Senior Scientist at the Istituto Italiano di Tecnologia in Genova. Professor Prattichizzo will discuss his new book “Il Corpo Artificiale” (Raffaello Cortina Editore), an essay that explores two synergies: the connection between engineering and neuroscience, and the collaboration between himself and Professor Simone Rossi, who teaches neurology at the same university and is a co-author of the book. Thanks to their cooperation, some of the most interesting neurorobotics solutions of the last few years have been developed.

VBRRII: Professor Prattichizzo, you work with augmentative robotics. Could you explain what it is?

PRATTICHIZZO: “To understand what augmentative robotics is, I need to make a comparison with collaborative robotics. I’ll help myself with an example. If I were tetraplegic due to a spinal cord injury and invited my girlfriend over, I wouldn’t want a collaborative robot to serve her something to drink. I would rather do that myself. I would prefer to have robotic supernumerary arms that I could control to pour a drink into a glass. Thanks to this example, it is easy to understand how augmentative robotics can enable individuals to maintain a central role in using technologies to perform tasks. This has nothing to do with a ‘butler’ robot that operates independently, rendering me irrelevant to the action”.

What technological requirements are necessary to create a paradigm of augmentative robotics?

“The most important element of augmentative robotics is a sensorimotor interface that allows for connecting human motor control with the control of the supernumerary robot. In the event of vocal control, we would not achieve the integration between human and robot that we would obtain with the residual movement of my shoulder, hand, mouth, or any other part of my body. So, we need a sensorimotor interface that establishes a connection between the sensorimotor functions of a biological human and the artificial system of a robot, integrating its loss of functionality. Just to be clear: I cannot control all of the robot’s parameters, so it must maintain a certain degree of autonomy. However, I can control some of them. More specifically, I need to control the parameters that give me the sensation of having direct control of the robot, like the wrist rotation that allows me to pour the drink into the glass”.

The perfect example of augmentative robotic is the sixth finger, isn’t it?

“Yes, and this is one of the inventions of which I am most proud. It arises from the desire to enable people with a paralyzed hand, which is closed due to the disease, to grasp objects. After all, you only need a palm and a thumb to grip a phone, a piece of paper, or a pen. So, our idea was to use the paralyzed hand as if it were a palm and provide the patient with an extra robotic thumb, attached to a special bracelet, and able to unroll when needed to stand opposite to the hand-palm and restore grip functionality”.

What impact does the presence of an extra sixth finger have on brain plasticity?

“This is a topic that Professor Simone Rossi has extensively researched. His research confirmed our expectations: The sixth robotic finger is integrated into the body’s representation schema within the brain. In particular, the sixth finger takes up space within the representation of the physiological fingers and is utilized in all predictive models for movement control. How fast is the process of integration? It can be very fast if the sensorimotor interface is set up in an ecological manner, such as enabling the user to close the robotic thumb by closing the thumb on their healthy hand with coordinated and natural movements of other body parts”.

If the interface is perfectly set up, can the sixth finger play an important role in the rehabilitation of someone who has suffered from a stroke?

“Without a doubt. Due to upper limb disability, individuals lose the ability to grasp objects, as well as motivation to move their limb, strength of the muscle-bone system, and cognitive control. By stimulating the use of their limb, the robotic thumb helps individuals to regain at least some of what they’ve lost”.

Where are we in terms of the development of tactile technologies? And why are they so important?

“If tactile technologies were TV screens, I would say that we are able to produce high-quality black-and-white images. We are at a good point, but there is still a lot to do. These technologies are important for many reasons. They are necessary for the sensorimotor integration of augmentative robotics, such as the sixth finger, which must be able to perceive the objects it grasps, rather than only executing movements. These technologies are also essential for virtual reality and augmented reality applications, telemedicine, and emotional communication. During the COVID-19 pandemic, patients in hospitals often experienced what is known as ‘skin hunger’: they missed the physical, human touch. So, with the startup WEART that I have co-founded, we have developed an application that allowed isolated patients to connect remotely with a relative and feel the touch that the person on the other side of the screen is experiencing on themselves”.

You have also developed ankle braces that produce vibrations to help Parkinson’s patients regain their gait. How do they work?

“In reality, these tools were invented as social communication tools to allow two people far away from each other to take a walk together. When one of them starts walking, the ankle brace sends a signal that translates into a vibration to the braces worn by the other person. As a reflex, this person adjusts their walking speed to match the rhythm of the other person”.

How did you adapt them for Parkinson’s patients?

“The application to Parkinson’s disease has been studied in collaboration with Professor Simone Rossi, an expert in the field. One consequence of this disease is a problem with motor control. In particular, there is a dysfunction around the basal ganglia, which are sorting stations along the motor descending pathways. In addition to motor neurons, these pathways target spinal interneurons that help coordinate complex motor responses, such as postural adjustments. One of the consequences is the freezing of gait (FOG): the patient freezes while walking and is unable to lift his feet from the floor, often resulting in a fall. To overcome the impasse, we typically use acoustic and visual stimuli, such as the sound of a metronome or a black and white checkered floor, to trigger a brain reset. We have applied the same principle to the ankle braces: by using alternating vibrations from one foot to the other, we restore the patient’s walking rhythm. In our case, however, the stimulus is more direct and therefore easier to perceive”.

The principle of reset is evident in another invention.

“Yes. Together with Marco Mandalà, an ENT specialist and professor at the University of Siena, we developed a device to control tinnitus, which arises from a brain difficulty in interpreting signals. Once applied to the mastoid bone, this technology produces vibrations that are not captured by the acoustic spectrum but redirect the neuronal circuits’ focus toward a more accurate interpretation of the acoustic inputs”.

In the intersection of robotics and neuroscience, what else is needed to further drive innovation?

“We need a large-scale vision. We must learn to live alongside robots with extraordinary abilities, far surpassing our own. If we venture into the microscopic scales, for example, a robotic tool is much more precise than a human hand. At the same time, artificial intelligence is more effective than the human mind at making calculations or memorizing people’s faces. Let’s not forget that these technologies must improve our lives. Therefore, we must collaborate with ethics experts and philosophers to achieve the right impact on our society”.

Technological progress moves quickly.

“This is true. In the past, we had much more time to understand what could have happened. While nowadays, as we try to comprehend the impact of a new discovery, another discovery immediately arises. Due to this rapid evolution, it is difficult for the human mind alone to foresee the consequences of these innovations. But we have a solution. We can use artificial intelligence to develop predictive tools that complement human efforts in finding the right ways to advance technology”.

What is your vision for the future of robotics?

“Today, robots are made of plastic and metals, which are difficult to dispose of. In the near future, we will use less processed and more natural raw materials, such as textiles, which will also enhance the wearability of robots. Thanks to this innovation, rehabilitation will take another step forward”.