BIDS Naming Convention - Adding a suffix?

If you wanted to add a suffix to sub-01 so that you can add your own participant identifier and/or group (i.e. control or patient), would that be allowed? e.g sub-01_a

If not, are there any workarounds? I find that this makes building 2nd level models easier when you can quickly add all participants with a certain suffix.

Many thanks for your help,

This information is usually stored within your participants.tsv file.


From the standard:

<label> - an alphanumeric value, possibly prefixed with arbitrary number of 0s for consistent indentation, for example, it is rest in task-rest following task-<label> specification. Note that labels MUST not collide when casing is ignored (see Case collision intolerance).

Couldn’t you name them sub-01a? The subject label 01a is alphanumeric and completely valid according to the standard.