1. Neurology Research Group; Division of Neurology; Department of Medicine; University of Cape Town; Cape Town South Africa
2. Department of Medicine; University of Cape Town; Cape Town South Africa
3. Drs. Du Buisson, Kramer, Swart & Bouwer, Inc.; Centurion Gauteng South Africa
4. National Health Laboratory Services and Division of Chemical Pathology; Department of Clinical Laboratory Services; University of Cape Town; Cape Town South Africa