1) PML diagnostic criteria: Consensus statement from AAN Neuroinfectious Disease Section and 2) Topic of the month: Stroke trials. 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. Andy Southerland interviews Dr. Joseph Berger about the consensus paper from the PML Guidelines Committee of the AAN Neuroinfectious Disease Section. Dr. Andy Numis is reading our e-Pearl of the week about spinal epidural abscesses. In the next part of the podcast Dr. Brett Kissela interviews Dr. Marc Chimowitz about SAMMPRIS trial. The participants had nothing to disclose except Drs. Berger, Numis, Kissela and Chimowitz.Dr. Berger serves as an Associate Editor for the Journal of Neurovirology, serves as an editorial board member of ISRN Education, Neuroscience, World Journal of Rheumatology and MS and other related disorders; serves on the PML adjudication committees of Millenium/Takeda and Amgen; has served as a consultant to Millennium/Takeda, Amgen, Genzyme, Eisai and Novartis; and receives honoraria from Genzyme. Dr. Numis serves on the editorial team for the Neurology® Resident and Fellow Section. Dr. Kissela serves on scientific advisory board for Allergan, Inc.; has received funding for travel and speaker honoraria from Allergan, Inc.; has received research support from the NIH, will receive compensation from Reata Pharmaceuticals, Inc. for serving on the Event Adjudication Committee for the BEACON study, which they are sponsoring. and provides medico-legal reviews.Dr. Chimowitz serves as an editorial board member for the journals Stroke and Neurosurgery; has received grant support from NIH/ NINDS to lead multicenter trials on the treatment of intracranial arterial stenosis; for these NIH funded trials, he has also received research support from Stryker Corporation (donation of intracranial stents, payments for 3rd party monitoring of trial), AstraZeneca Corporation (donation of statin), Bayer (donation of aspirin and placebo) and Bristol Myers Squibb (donation of warfarin and placebo); serves on the data safety monitoring board for an industry funded PFO closure study sponsored by Gore Corporation and on a stroke event adjudication panel for an osteoporosis trial funded by Merck and has also provided medico-legal reviews on stroke related cases.