1. Department of Internal Medicine, University of Zambia School of Medicine, Lusaka, Zambia
2. Department of Neurology, Harvard Beth Israel Deaconess Medical Center, Boston, MA, USA
3. Department of Medicine, University Teaching Hospital, Lusaka, Zambia
4. Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
5. Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
6. Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA