First publication in the Parkinson Vibrating Socks project
With the first publication in the Parkinson Vibrating Socks project, we have succeeded in laying the foundation for the project's progress. The current publication describes a method that allows gait data and brain activity to be recorded with high temporal synchronization in the virtual reality environment of the GRAIL system.
The high temporal synchronization of the measurement method was demonstrated by replicating known physiological phenomena. Two different experiments were conducted for this purpose. First, the participants were shown a checkerboard pattern, which changed the field colors (black and white) at regular intervals. These changes trigger a well-known reaction in the brain, which was measured and compared to expected reactions. In a second experiment, the participants took steps forward. A brain reaction related to the initiation of movement was measured and compared to the expected reaction.
To measure brain activity, two different methods were used: electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). EEG measures electrical activity in different areas of the brain using electrodes placed on the scalp. fNIRS measures oxygen supply in the brain using light beams that are sent through the skin. An increased oxygen level indicates increased brain activity. Since EEG captures fast electrical signals and fNIRS detects slow changes in blood flow, the combination of the systems provides more comprehensive information about brain activity than using either system alone.
The study aimed to record EEG and fNIRS data synchronized with movement data and visualizations in the VR environment. A photodiode and a special mini-computer were used for this. The synchronization of the measured brain activity with the visualizations in the VR environment was tested using the first experiment, the checkerboard pattern. After a color change, a specific reaction in the brain is expected after a precisely defined time, which is recorded by the EEG. In this study, ground reaction forces were used as movement data, allowing the detection of each step as well as the initiation of movement. In the second experiment, the initiation of movement was linked to a subsequent increase in brain activity in the relevant brain areas.
The experiments confirmed the expected brain reactions. The first experiment showed high accuracy in the millisecond range, while the second experiment demonstrated the synchronization of movement data with the brain activity measurement methods. The study thus showed that the measurement systems can be used for further experiments.
The measurement systems will continue to be used in the Parkinson Vibrating Socks project to evaluate vibrating socks in our virtual environment. These vibrating socks are intended to help people with Parkinson’s prevent freezing of gait.
In summary, the study demonstrated that our measurement system is capable of recording brain activity and movement data with high synchronization. The measurement system can therefore be used in upcoming experiments within the Parkinson Vibrating Socks project.