I don't know about that exactly, but my understanding was that this is similar in justification to compelling a person to be fingerprinted or give a DNA sample. To me there does seem to be a fairly major difference between forcing someone to disclose information held in their mind and forcing them to provide a biometric. The former seems equivalent to compelling testimony against oneself. I have a hard time seeing the latter as compelling testimony against oneself, especially if giving fingerprints or DNA isn't.
Part of it is that compelling information can be problematic, in that other circumstances can happen where the information may not easily be obtainable.
Extreme example, imagine a stroke or head injury causing memory loss.
OTOH DNA/Face/Fingerprints, usually can't be 'forgotten'.
