Is it beneficial to take dietary supplements such as alpha lipoic acid, acetyl l-carnitine, and phosphatidylserine for parkinson's?

Yes. While more research is needed, there is a good amount of science on the benefits of each of these on neurologic function. They are certainly safe to try and if i had parkinson's i would take all of those and more. See http://www.Needs.Com/product/ndnl-0404-02/l_acetyl_l_carnitine ; http://www.Lef.Org/protocols/neurological/parkinsons_disease_03.Htm.