Laterality of an EEG anxiety disorder biomarker largely follows handedness

Anxiety disorders are the most common mental disorders impacting people worldwide. Using an auditory Stop Signal Task (SST), we have developed an anxiety disorder biomarker (goal-conflict specific rhythmicity/GCSR) that occurs at the right frontal site F8 in righthanded participants. Here, we compare its laterality in left-handers (n ¼ 26) versus demographically-matched right-handers (n ¼ 26) between the ages of 18e30. We assessed the effects on GCSR power of the handedness of the participants (left or right), blocks of the SST, lefteright variation across frontal channels (F7, F3, Fz, F4, F8), and EEG frequency (4 e12 Hz). Left-handers differed from right-handers most at the channels furthest from the midline. This difference was largely a mirroring of right hander responses by left handers. With frontal channels coded in reverse order for left handers the original significant differences disappeared. Some differences remained between the groups in the frequency variation across blocks of testing. These and other data suggest that the circuitry engaged by conflict in the SST is different from that directly controlling stopping behaviour. Our results also suggest that where GCSR is used as an anxiety process or disorder biomarker in groups that combine both left and right-handed people, data only from the channel ipsilateral to the dominant hand should be used (F7, or F8, respectively).