"The new study, published in the June 23 edition of the Lancet, aimed to test the safety and tolerability of the procedure, which involved surgical implantation of billions of copies of a single gene into the brains of 12 Parkinson's disease patients. None of the patients experienced any side effects following the single-injection procedures, and after one year of monitoring, all patients experienced some level of improvement in symptoms on the side of their bodies that correlated to the side of the brain that had been treated. (The other side of the brain was left untreated in each patient in order to establish a control.) "

Well here is a solution without using sham surgery - treat one side of the brain only. The other side of the brain remains untreated as a control. Sounds good to me.