1. Georgetown University Hospital, Washington, DC, USA.
2. South Shore Neurologic Associates, Bay Shore, NY, USA.
3. Mellen Center for Multiple Sclerosis Treatment and Research, Cleveland Clinic Foundation, Cleveland, OH, USA.
4. University at Buffalo, Buffalo, NY, USA.
5. Braintree Rehabilitation Hospital, Spasticity Management Program, Braintree, MA, USA.
6. Multiple Sclerosis Research Center of New York, New York, NY, USA.
7. National Hospital for Neurology and Neurosurgery, London, UK.
8. Spaulding Rehabilitation Hospital, Boston, MA, USA.
9. Centro Studi Sclerosi Multipla, S.Antonio Abate Hospital, Gallarate, Italy.