Patients also don't usually know what is useful or not for a Doctor to diagnose them (or any medical provider usually). That has to be picked out as part of the Doctor or other medical provider questioning them and getting their vitals.

Some of it is implicit, like 'is the person able to form cogent sentences', or 'does the patient seem to be struggling to stand'. Others are more explicit, like heart rate, BP, 'what medicines are you taking', etc.

Often the ones who need the most help are the worst at getting anything useful out.