MAO-B inhibitors (more specifically selegiline which contributes most of the data) do not appear to delay disease progression in terms of improved survival but may reduce later motor fluctuations. At present, we do not feel these drugs can be recommended for routine use in the treatment of early Parkinson's disease.
Time course of physical and psychological responses to selegiline monotherapy in newly diagnosed, idiopathic parkinsonism.
Poor specificity of face-value endpoints and the poor sensitivity of gross clinical examination may have militated against demonstrating prophylaxis by selegiline.
                Objective measures of the four cardinal signs were used as primary outcome criteria in a randomised, double-blind, placebo-controlled, parallel group study of selegiline monotherapy in 25 newly diagnosed elderly sufferers from idiopathic parkinsonism, stratified for sex and Hoehn and Yahr functional staging.
                There was a significant interaction between time and nature of treatment with respect to rigidity. The effect of time during active treatment was highly significant: rigidity decreased by 1.3% per week. The worsening of rigidity on placebo was not statistically significant. Neuronal rescue is a possible explanation for the long term, progressive improvement produced by selegiline. No significant treatment effect was seen on the other cardinal signs. However, there was a significant quadratic time trend for arousal on active treatment suggesting tolerance to this effect.
                The difference in time course between the psychostimulant and physical effects suggests more than one mode of action.