Created by designer Dani Clode and her colleagues, this unique Third Thumb augmentation device is a 3D-printed robotic digit that is worn opposite the natural thumb, below the pinky finger. The researchers say that the device can be controlled by moving your toes; with the help of a pressure pad beneath the sole of the wearer's foot.
What does this new robot thumb do?
Dani and her team gave 36 participants, all right-handed, the prosthetic thumb and studied them using the device in a five-day training period. During the training sessions, the participants were given a series of reaching, grasping, and manipulation tasks like picking up multiple balls or wine glasses with one hand.
The routines were focused on motor control, coordination, and dexterity, and were aimed to teach the volunteers to use the Third Thumb instinctively. The team wanted to see if the robotic thumb can perform tasks together with the other fingers. They found that while using the robot thumb, the test subjects were able to carry out difficult tasks such as doing math while using the Third Thumb to build blocks and even holding a cup while stirring with the remaining natural fingers. Some even used the thumb to flick through pages of a book they were holding in the same hand.
Furthermore, the test subjects were also encouraged to perform some normal activities using the robot thumb at home for several hours a day.
This isn’t all. The report says that to understand the effect of the extra thumb on the participants’ brains, the researchers gave them an MRI scan before and after the experiment. The neural scans revealed that the presence of the third thumb made the brain recognize each finger as more similar to each other than it did before the experiment. However, when the participants returned to the lab a week later, the effect of the brain changes had largely receded. According to the researchers, this demonstrates that our brains seem to adapt pretty quickly to an added robotic appendage. To sustain these neural changes, however, regular use of augmented devices will be needed.
“Our study shows that people can quickly learn to control an augmentation device and use it for their benefit, without overthinking. We saw that while using the Third Thumb, people changed their natural hand movements, and they also reported that the robotic thumb felt like part of their own body,” Clode said in a statement.
What’s the significance of this invention?
Clode says that she designed the Third Thumb as a project “seeking to reframe the way we view prosthetics, from replacing a lost function, to an extension of the human body.” The study she and her team undertook shows the usefulness of motor augmentation and that with proper training, humans can indeed use such augmented devices judiciously.
The researchers aren’t just excited with the fact that the volunteers were able to perform complex tasks using their device; what's particularly pleasing to them is that they managed to move the thumb even when distracted or blindfolded. Furthermore, the test subjects reported a strong sense of embodiment while wearing the augmentation device.
Of course, they will need to test a larger group of human subjects for a longer period to prove the device’s true capability. But the initial results do show promise. In fact, neuroscientists have been surprised at how quickly participants adapted to the thumb.
Remember that evolution hasn't equipped us to use an extra body part. The prospect of working in conjunction with something that’s physically attached to our body is therefore interesting. Perhaps long-term use of such devices can lead to a change in the brain's representation of the fingers where it may see less of a difference between them with time.
This is something that needs to be explored further and more advanced robotics and prosthetics like the Third Thumb can help achieve that.
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Body augmentation can be useful in more ways than just stirring a cup of coffee. It can help a surgeon perform their task without an assistant. It can even enable factory workers to work more effectively. More importantly, it can help people who can only use one hand to perform all the tasks with that very hand. To get there, however, more research would be needed to determine how these devices interact with the human brain.
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