1. Department of Physical Medicine and RehabilitationJohns Hopkins School of MedicineBaltimore Maryland USA
2. Department of NeurologyJohns Hopkins School of MedicineBaltimore Maryland21205 USA
3. Department of Physical EducationKongju National UniversityGongju Republic of Korea
4. Department of Physical Medicine and RehabilitationVA Caribbean Healthcare SystemSan Juan Puerto Rico
5. Department of MedicineJohns HopkinsBaltimore Maryland USA