Fig. 1From: Protocol of a randomised delayed-start double-blind placebo-controlled multi-centre trial for Levodopa in EArly Parkinson’s disease: the LEAP-studyDelayed-start design. Studies with a delayed-start design investigate two agents: active treatment (solid line) and controlled treatment (dashed line). In phase 1, patients are randomised to either active (levodopa) or controlled (placebo) treatment. In phase 2, both groups receive active treatmentBack to article page