Relationship between passive movement speed and sensorimotor rhythms recorded by dry-electrode EEG

Fumiaki Iwane (1451015)

This thesis investigates the relationship between the speed of periodic passive movements, induced by an assistive robot, and the sensorimotor rhythms recorded by dry-electrode EEG. Indeed it is necessary to understand whether the baseline power of the sensorimotor rhythms is affected by robot speed changes, leading to unpredictable behaviours of the brain machine interface (BMI).

To this end, we conducted an experiment with 13 subjects. In the experiment, a one degree of freedom robot was worn at the level of the left elbow and oscillated their left arm at different speed levels, while recording the subjects' brain activity. In order to have a point of reference, additional trials were collected, where subjects rested, or performed motor execution of their left arm at different speed levels, with the help of a metronome.

As a result, we found that both alpha and beta event related desynchronization (ERD), induced by the passive movements, did not vary as a function of speed. However, power of both alpha and beta band during motor execution were stronger than those of passive movement.

The findings of this study may help researchers to design advanced brain robot interface (BRI) rehabilitation paradigms, in which the robot provides continuous reliable proprioceptive feedback to patients.