 The Symbol Digit Modalities Test SDMT is a sensitive and validated test of cognition in MS. CogState offers a standardized battery of cognitive tests frequently used in clinical research in the fields of dementia and Parkinsons disease. The CogState battery of tests consisting of the Detection test processing speed, Identification test attention, One Back test working memory, International Shopping List test verbal learning and the Groton Maze Learning test reasoning and problem solving will further confirm and validate the results of the SDMT in MS patients as well as examine other cognitive domains. 