Hi Rebecca,
The maximum (preferably censored) motion displacement is a consideration for potential distortion differences, assuming a fixed shim at the beginning of a scanning run. The shim corrects distortion, but as the subject moves, the distortion changes.
The maximum displacement is the largest displacement between *any* pair of volumes (probably not including censored volumes).
For example, in
AFNI_demos/AFNI_pamenc/AFNI_02_pamenc/global_process_commands.txt, we used gen_ss_review_table.py to drop subjects having a maximum censored displacement greater than 8 ~mm.
Does that seem reasonable?
- rick