1. Department of Neurology, University of Texas Southwestern Medical Center, Dallas, Texas, U.S.A.;
2. UT Southwestern Medical School, Dallas, Texas, U.S.A.;
3. Department of Neurology, University of North Carolina, Chapel Hill, North Carolina, U.S.A.
4. Department of Pediatric Neurology, University of North Carolina, Chapel Hill, North Carolina, U.S.A.; and
5. Department of Pediatric Neurology, Children's Medical Center/UT Southwestern, Dallas, Texas, U.S.A.