Trial designs used to study neuroprotective therapy in Parkinson's disease


  • Anthony E. Lang MD,

    Corresponding author
    • Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J Safra Program in Parkinson's Disease, Toronto Western Hospital, Toronto, Ontario, Canada
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  • Eldad Melamed MD,

    1. The Norma and Alan Aufzien Chair for Resarch of Parkinson's Disease, Tel Aviv University, Sackler School of Medicine, Tel Aviv, Israel
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  • Werner Poewe MD,

    1. Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
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  • Olivier Rascol MD

    1. Clinical Investigation Center and Department of Clinical Pharmacology and Neurosciences, CIC9302 INSERM and UMR825, Toulouse University Hospital, University of Toulouse-3, Toulouse, France
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  • Relevant conflicts of interest/financial disclosures: Nothing to report.

  • Full financial disclosures and author roles may be found in the online version of this article.

  • Funding: This work was partially funded by a Center of Excellence grant to Anthony E. Lang from the National Parkinson Foundation.

Correspondence to: Dr. Anthony E. Lang, Movement Disorders Center, Toronto Western Hospital, 399 Bathurst St, 7 McL, Toronto, ON, Canada M5T 2S8;


There have been numerous trials conducted to evaluate putative disease-modifying or neuroprotective treatments in Parkinson's disease. These trials have used several different study designs and outcome measures. Each of these has its own strengths and weaknesses. Confounding all studies is the potential symptomatic benefit that the treatment might have on the features of Parkinson's disease. In addition, patient-related factors such as age of onset and the nature of the dominant symptoms may have important impacts that are often not addressed. Here we provide an overview of the various trial designs that have been used and emphasize the challenges faced in attempting to study neuroprotection in Parkinson's disease and the advances needed before this goal can be successfully achieved. © 2013 Movement Disorder Society