We are doing chelation with our autistic son and from what I gather, it can take 2 years+ to complete chelation with children.
DMSA is great, Alpha Lipolic Acid will cross the blood brain barrier though to get the Hg out of there. DMSA can't.
Look at http://www.amalgamillness.com Andrew Cutler has a protocol for these that is very safe, I am going to be doing it when I get my fillings totally out. You can't chelate with any fillings!!!!