1. Department of Neurology; School of Medicine; University of Ioannina; Ioannina Greece
2. Neurosurgical Research Institute; University of Ioannina; Ioannina Greece
3. Department of Internal Medicine; School of Medicine; University of Ioannina; Ioannina Greece
4. Second Department of Neurology; School of Medicine; University of Athens; Athens Greece
5. Department of Neurology; University of Tennessee Health Science Center; Memphis TN USA