I know from personal experience what Aspartame can do. I spent about three years trying to find out why I had permanent tiredness, dizzy spells and blurred vision, as well as some really strange turns which were similar to pre-frontal lobe epilepsy. Myriad tests by the doctor found no reason. By chance I read an article on sweeteners and there, under Aspartame, were all the symptoms that had dogged me for so long. Then I started reading labels.
It is amazing how much of this stuff is in what we buy. Even some of the vitamin and mineral 'berries' that I took daily had this in them. Stopped taking any Aspartame, symptoms disappeared. If I take the stuff in by accident I get the symptoms back.