One of the earliest clinical studies to examine neuroprotective effects in MAO-B inhibitors has been the Deprenyl (= selegiline) and Tocopherol Antioxidative Therapy of Parkinson (DATATOP) trial, in which 800 patients with early PD were randomized to four treatment arms: 1) tocopherol placebo and selegiline placebo, 2) 2000 IU tocopherol per day and selegiline placebo, 3) tocopherol placebo and 10 mg selegiline per day and 4) 2000 IU tocopherol and 10 mg selegiline per day [4,66]. Here, MAOB is linked to Parkinson disease.