1) Progressive multifocal leukoencephalopathy and 2) Topic of the month: Featured speakers from the AAN Meeting. This podcast for the Neurology Journal begins and closes with Dr. Robert Gross, Editor-in-Chief, briefly discussing highlighted articles from the print issue of Neurology. In the second segment Dr. John Scagnelli interviews Dr. Sandra Richman about her paper on progressive multifocal leukoencephalopathy. In the next segment, Dr. Sarah Song is reading our e-Pearl of the week about sickle cell disease and stroke. In the next part of the podcast Dr. Alberto Espay interviews Dr. Stephen Hauser about the Robert Wartenberg Lecture. The LOTWs for the next two weeks of May will be interviews with Drs. Griggs and Daube. The participants had nothing to disclose except Drs. Richman, Song, Espay and Hauser.Dr. Richman is a full-time employee of Biogen Idec.Dr. Song served on the editorial team for the Neurology® Resident and Fellow Section. Dr. Espay serves on scientific advisory boards for Boehringer Ingelheim and Solvay Pharmaceuticals, Inc.; serves on the editorial advisory board for The European Neurological Journal; has received speaker honoraria from UCB/SCHWARZ PHARMA, Medtronic, Inc., and Novartis; has received honoraria from Novartis, the American Academy of Neurology, and the Movement Disorders Society; has served on speakers' bureaus for UCB/SCHWARZ PHARMA and Novartis; receives/has received research support from Medtronic, Inc., Allergan, Inc., CleveMed, the KL2 Research Scholars mentored career development award, and NIH Institutional Clinical and Translational Science Award (RR026315-02), Dean Scholar's Award - University of Cincinnati, Davis Phinney Foundation, and the Michael J Fox Foundation. Dr. Hauser has served as both a scientific advisory board member and consultant to BioMarin Pharmaceutical Inc. and Receptos Inc., and as a consultant to Novartis; has received travel accommodations from Roche; his institution (UCSF) has received speaker honoraria from Wyeth-Pfizer Inc; serves as Editor-in-Chief of Annals of Neurology; receives publishing royalties for Harrison's Principles of Internal Medicine (McGraw-Hill Publishers, 1994-present); and has received stock options from Receptos Inc., all of which were transferred to his institution (UCSF).