Question scores are combined to form 7 ‘component’ scores, each of which has a range of 0–3 points (0=no difficulty, and 3=severe difficulty). The seven component scores are then added to yield one ‘global’ score with a range of 0–21 points. A score of zero indicates no difficulty sleeping while a score of 21 indicates severe difficulties in all areas. Cognition is measured using the Symbol Digit Modalities Test (SDMT). The SDMT has been shown to be sensitive to cognitive impairment in MS.51 This test was originally developed for use with persons with Huntington’s disease and was adapted for use with persons with MS. It specifically measures psychomotor speed, attention and integration of information. It is the standard outcome used to measure cognitive processing speed in persons with MS, nation- ally and internationally.