The purpose of this study is to assess the impact of Natalizumab (Tysabri) therapy on sleep efficiency, total sleep time and sleep latency, in Multiple Sclerosis (MS) patients receiving Natalizumab for 6 months relative to baseline.

Natalizumab has been shown to positively impact fatigue and cognition. The mechanism by which this occurs is unknown. Change in quality of sleep is one possible etiology of these findings. This study will help to elucidate the mechanisms that lead to reduced fatigue/sleepiness and less cognitive dysfunction in MS patients who go on Natalizumab therapy. Understanding these factors may help neurologists better differentiate between the different therapeutic options for MS and how they may impact symptoms that negatively affect quality of life.

Inclusion Criteria:

• Relapsing form of multiple sclerosis
• Able to give informed consent and committed to follow the protocol
• EDSS from 0 to 6.0
• Epworth Sleepiness Scale > 9 or Modified Fatigue Impact Scale > 30 or Fatigue Severity Scale > 4
• Age range of 18 - 65 years of age
• Naïve to Natalizumab
• Enrolled in the TOUCH program

Exclusion Criteria:

• Severe cognitive impairment
• Coexisting severe medical condition
• Inability to speak English or read
• Inability to give valid informed consent.