What is the "Algernon-Gordon Effect" in "Flowers for Algernon?"

The "Algernon-Gordon Effect" is the discovery that Charlie makes regarding the fact that his intelligence gain was only temporary.  It is the name of a report that he writes for the Welberg foundation that says that all the intelligence he gained will eventually be lost and that the speed of the loss increased the more intelligent one became from their previous level.  In short, the smarter you got, the faster it would all go away.  Ironically, as his intelligence slipped away Charlie would eventually not even be able to read his own report.