The lab where robots help you walk again

Walking in the corridors of the Delft University of Technology’s  (TU Delft) Faculty of Mechanical Engineering, one can notice a lab crammed with cables, a treadmill, and several desks with robotic arms. It is the Motor Learning and Neurorehabilitation Laboratory (MLN Lab), led by Associate Professor Laura Marchal Crespo, applying technologies such as virtual reality (VR) and AI to develop therapy options for post-stroke patients.  

“In a way, I want to leverage the technologies we have at our disposal to create surreal training conditions. Think of the animated series Dragon Ball, where Goku used to train in a hyperbolic chamber with extremely high gravity. By simulating extreme or easier training conditions, we can optimally stimulate patients and help them in their journey to fully recover their motion abilities,” says the researcher. 

New ways to help post-stroke patients

The MLN Lab, where a dozen academics work, fosters a multidisciplinary approach including biomedical engineers, neuroscientists, and psychologists. After being established at the University of Bern, Switzerland, in 2017, the MLN Lab was moved to Delft five years ago.   

In the Netherlands, around 30,000 people suffer a stroke annually. There are two distinct forms of stroke: when blood flow to the brain is blocked (ischemic stroke), and when sudden bleeding in the brain occurs (hemorrhagic stroke). In addition to the damage a stroke can leave on the brain—such as memory loss—the limbs can also be affected, usually on one side. Those affected by the severest forms of stroke have to relearn from scratch how to hold a cup, walk, or write. 

Lengthy months of physiotherapy to recover motor functions await post-stroke patients. That’s why Marchal Crespo’s lab is working to develop effective and engaging methods to accelerate recovery. 

Relearning how to walk 

The largest device in the lab is the one used to regain walking abilities. Hovering a treadmill is a suspended harness connected to a robot—a proper exoskeleton with motors on the hips and knees. Using this setup, the robot can make walking easier or more challenging. Moreover, while moving their steps on this treadmill, patients also wear a VR headset. 

Being immersed in a virtual universe gives the walking a special twist. “We can fully customize their experience, making them walk on the moon or along a mountain trail. Patients who enjoy a challenge find it stimulating. Yet, for some, it can be overwhelming, and walking becomes tougher,” underlines the scientist. 

Nevertheless, engaging patients in such a way is essential to provide a multisensory experience, stimulating as many areas of the brain as possible. Although the researchers can’t track the brain activity while engaging in these activities, they can notice the positive effects and how they can effectively help regain abilities. 

Studying patient psychology

Alberto Garzás Villar, one of the lab’s PhD candidates, researches patient characteristics. These include psychology and social environment, specifically how these factors affect the way they engage with recovery therapies. By understanding how different patients react, the goal is to accumulate knowledge to develop personalized therapy options. 

As part of his research, he analyzes how patients behave while using the Lambda3+, a robot developed by Delft researchers in collaboration with robot company Force Dimension. Using this device, patients work on hand training. Users can easily place their hands into a specially designed device equipped with motors that can respond to movement. The device can provide the sense of touching virtual objects while playing games. “The robot’s movement is fully customizable for each patient,” explains the researcher.

Using this robot, patients don’t simply exercise to move their hands again, but engage in several video games. In one, they use a slingshot to hit ghosts; in another, they play as bartenders filling up different-shaped cups, squeezing bottles with varying resistance that can be realistically felt in your fingers. 

Laura Marchal Crespo working on the Lambda3+ robot - © Delft University of Technology

Expanding care options 

As Marchal Crespo says, “The more you practice a movement, the better. It's similar to learning how to execute the perfect tennis serve. You need infinite repetitions.”’ To this extent, a part of her lab efforts is for developing cheaper and more compact devices to make care options more accessible and suitable for home use. 

Even the bulky and expensive treadmill setup can be replicated at home using elastic bands, with the healthy leg helping to support the paralyzed one. To make hand training more accessible, the researchers developed a portable hand trainer. This minimal device features a flexible shell and a tiny motor to provide feedback when interacting with objects. Even with this minimal setup, the same game of filling cocktail bar cups can still be played, experiencing sensory feedback. 

No easy way to the market 

Despite all the work and effort, these innovations often struggle to reach the market. As medical devices, they must comply with many standards. And while these rules are essential to safeguard health, they are, in some cases, restraining innovation development. For instance, during the development phase, testing with patients is not always permitted. 

This is a clear disadvantage for the researchers, who cannot thoroughly test the devices they are working on. “Ultimately, our research doesn’t reach the patients, lacking the impact these innovations could have,” underlines Marchal Crespo. 

While patient acceptance doesn’t represent an issue, companies’ openness doesn’t lack either; the strict compliance standards stand as a significant hurdle. Nevertheless, the MLN Lab stays committed to its mission, making its post-stroke recovery technologies available to patients.