[1] VA Greater Los Angeles Healthcare Syst, Dept Neurol, Parkinsons Dis Res Educ & Clin Ctr PADRECC, Los Angeles, CA 90073 USA
[2] Univ Calif Los Angeles, Dept Neurol, Los Angeles, CA 90024 USA
[3] Prov Hlth Syst, Prov Med Grp, Newberg, OR USA
[4] Philadelphia VA Med Ctr, PADRECC, Philadelphia, PA USA
[5] Univ Penn, Dept Neurol, Philadelphia, PA 19104 USA
[6] Yale Univ, Dept Neurol, New Haven, CT USA
[7] Neurol Neurosurg & Spine Clin S Georgia, Valdosta, GA USA
[8] VA Greater Los Angeles Healthcare Syst, VA Ctr Study Healthcare Provider Behav, Los Angeles, CA 90073 USA