Psychologist Josef Meekes is investigating neurofeedback - a method that could help paralysed stroke patients to relearn certain movements. In February, he received a "Carl von Ossietzky Young Researchers' Fellowship" from the university.
Most people don't have to think about it when they want to close a hand into a fist. However, many stroke patients find such natural movements extremely difficult. Half-sided paralysis of the upper limbs is one of the most common impairments that remain after a stroke. "Those who suffer from severe paralysis in particular have very few opportunities to improve their situation," says Dr Josef Meekes.
The scientist, who has been working in the Department of Neuropsychology since 2015, wants to change this. He is working on a method in which patients first train their brain so that they can later regain control of their limbs. It has the complicated name "Motor Imagery Neurofeedback Training". This is a combination of two methods: "motor imagery" means "visualisation of movement". Among athletes, this practice is also known as mental training. Movements are only performed in the mind - but also improve in reality. "This is because the imagination of a movement and the actual execution activate the same areas in the brain," explains Meekes. He therefore hopes that mental training can make limbs that are paralysed due to brain deficits more mobile.
As it is difficult for both outsiders and the patients themselves to check whether they are visualising the desired movement correctly, Meekes combines mental training with neurofeedback: he records the patient's brain waves using an electroencephalogram (EEG). A computer programme evaluates the data and uses an image signal to provide re-registering students with re-registration on how well they have completed a given task. In this way, Meekes hopes to teach patients to restore brain functions that have been impaired by the stroke.
Experiments in the neurolab
The experimental design looks something like this: The test subjects sit in front of a screen while 96 electrodes measure the electrical activity of their brains. At regular intervals, a blue area appears on the screen, either in the top right or top left corner. This is the signal for the test subjects to mentally clench the corresponding hand into a fist. If they do this well - which a computer program can recognise from the EEG - a white ball, which is initially located at the bottom centre of the screen, floats towards the blue area as if by magic. The stronger the imagination, the higher the ball rises. And if the patient succeeds in activating the right hemisphere of the brain, the ball also moves in the right direction.
In principle, patients could also be asked to actually perform the movement. "But it can be very frustrating if nothing happens," says the researcher. In Meeke's experiment, on the other hand, patients can directly observe the success of their efforts - which significantly increases motivation. The method also has advantages for therapists: they can recognise whether a patient is actually working on the task.
Neurofeedback also works for older people
Meekes has already been able to confirm that movement imagination and neurofeedback, as implemented in the Oldenburg neuropsychology laboratory, generate sufficiently strong EEG signals not only in young, healthy test subjects, but also in healthy older people and stroke patients. Last year, he was also involved in a study in which it was shown that feedback training can, in principle, also be carried out at home. In a feasibility study, three patients trained for half an hour every other day for four weeks. The researchers then recorded a significant improvement in the motor skills of at least one participant using standardised tests. They presented the results in the journal Clinical EEG and Neuroscience in 2017.
Meekes is passionate about working with those affected. "I want to use my research to make a concrete contribution to improving the situation of patients," he says. In future, however, the Dutch-born psychologist, who previously conducted research at the University of Utrecht, will probably spend less and less time in the lab himself. This is because the start-up funding from the university will enable him to set up his own research group. He is already supervising two Master's students and soon plans to submit an Emmy Noether proposal to the German Research Foundation (DFG) and expand his team.
The 39-year-old has exciting plans: to make neurofeedback training suitable for everyday use, he is increasingly focusing on the use and optimisation of mobile EEG devices. He is also investigating which psychological tricks can be used to increase the motivation of the test subjects - especially if the training is not initially successful. Another important aspect of his work is to be able to tailor the training to the individual patient as well as possible. At the moment, he and his colleagues are still struggling with the problem that the EEG signals are different for each person - they depend on the anatomy of the brain, for example. The researchers want to take these effects into account in order to improve the quality of feedback for patients.
Being able to write or knit again
In the long term, Meekes wants to demonstrate in a larger study that neurofeedback training after a stroke actually helps to regain lost movement skills. Being able to clench a fist is only the first step. "Patients want to be able to write, brush their teeth or knit again," reports the researcher. This means hard mental work: visualising intensively how muscles contract, skin tightens and joints bend.
