The human brain has the remarkable ability to adapt to learn new concepts and abilities. This trait is known as brain plasticity. Our study group asks the question: How can we harness this trait with the help of neurotechnology to help people who suffer from disabilities after brain damage? For example, in rehabilitation after a stroke?

Effects of Strokes on Motor Function

A stroke is a loss in brain function due to an acute disturbance in blood supply to the brain, retina or spinal cord. An example of this is the loss of motor skills occurring in brain areas involved in motor function. The World Health Organization estimates that one in every four individuals will suffer from a stroke in their lifetime. Therefore, stroke is one of the leading causes of disability worldwide and in Germany, where it has been estimated that 270,000 new cases occur annually.

One common outcome after stroke is a decrease in communication between the muscles and brain areas responsible for movement. This results in patients losing muscle tone and being unable to perform movements. Although current rehabilitation strategies lead to strong improvements about 6 months after stroke onset, once this time has passed, further recovery is challenging.

Neurotechnology-Based Rehabilitation Research

At the neurology department of the Max Planck Institute for Human Cognitive and Brain Sciences, my colleagues and I are currently researching neurotechnology-based methods to support stroke patients in their rehabilitation, even when more than 6 months have passed since the stroke. For this, our strategy is to increase brain plasticity with transcranial magnetic stimulation (TMS). The stimulation then promotes communication between the brain and muscles through training based on a brain-computer interface (BCI).

In TMS, magnetic fields are applied over the head to modulate the activity of neurons. Evidence suggests that TMS applied to certain patterns of stimulation can increase the likelihood of the occurrence of brain plasticity. Consistently, previous studies suggest that using repetitive TMS protocols can improve motor function in individuals with strokes. Therefore, we are using this non-invasive technique to facilitate and accelerate the learning of new skills and improve neuro-rehabilitation.

Graphic of TMS coil and EEG

BCI-based training uses machine learning to train a computer to recognize brain activity generated when hand movements are imagined. When the participant enters a motor imagery brain state, the computer recognizes it. A small current is then delivered into the arm to produce movement. Since the brain areas activated during the execution and the imagination of a movement overlap, this technology allows reinforcing brain activity associated with movement. This happens even when self-initiated movement is very difficult or not possible, which could help stroke patients in their rehabilitation.

Conclusion

We believe that by using these technologies, we can promote brain plasticity. This can possibly improve the motor skills of people who have suffered a stroke. In this way, we aim to address the challenge of rehabilitation for moderate-to-severe hemiparesis in chronic stroke.

For more information about our study, please refer to our web page, contact Aimee Flores at flores@cbs.mpg.de, or call +49 341 9940-2256.