I don't know @MEMarge . Sonya has mentioned that children use noticably different language - I think that she mentioned the use of fatigue more ( but could be wrong).What do AfME advise children to say?
The kids page on AfME was revamped after input from parents on Educate ME project as it simply did not reflect the seriousness of the illness and did not define PEM adequately. It was posiitve that AfME listened and changes were made; there is always room for improvement.
On forums there are exapserated posts of children's sympoms simply being dismissed at Bath if they do not correlate to expected responses, so it could very much be a learned response.