A Multi-center, Multi-regional Observational Study to Test the Responsiveness of the Validated MusiQoL (Multiple Sclerosis International Quality of Life Questionnaire) Instrument to EDSS Status Changes in Any Form of Multiple Sclerosis (MS) in Patients With or Without Treatment

Inclusion Criteria: 1. Patient has any form of MS (confirmed by McDonald and/or Poser criteria) 2. Patient is 18 years old or more (inclusive, at time of informed consent). 3. Patient has an EDSS score lower than 7.0 (inclusive, at time of informed consent) 4. Patient can be with or without treatment 5. Patient has read, understood, signed and dated informed consent form 6. Patient is able to fill in the questionnaire by him/herself Exclusion Criteria: 1. CIS Patient (MS not confirmed by Mc Donald and /or Poser criteria) 2. Patient receives or is planned to receive during the course of this study any investigational drug or experimental procedure 3. Patient suffers from dementia in the opinion of the investigator 4. Patient suffers of major medical or psychiatric illness in the opinion of the investigator