Unraveling Back Pain Chronicity: an EMG and EEG Study

240 trials of RAM in either a forward (50%) or backward (50%) shoulder flexion direction and back to neutral as fast as possible, with maintaining extension in the elbow. Visual cues (arrows) indicated the movement direction.

An unpleasant, but harmless, electrocutaneous stimulus is administered to the low back region in 25% of the threat trials during the fear condition. Due to a conditioning phase before testing, participants know to expect this stimulus after the presentation of a warning cue related to the fear trials (either pink or blue dot dependent on randomization).

In all trials, during the presentation of the warning cue, a vibrotactile stimulus is administered to the low back region. This stimulus is used to evoke somatosensory evoked potentials (SEP) measured with EEG during the movement-preparation phase.