Effect of Acetominophen an Gait Fatigue in Multiple Sclerosis

The goal of this observational study is to compare the impact of an antipyretic, acetaminophen to a placebo on gait fatigue in persons with multiple sclerosis (MS). The primary question this study is asking is the following: will the antipyretic effects of acetaminophen result in less gait fatigue in persons with MS? Participants will be asked to come for two sessions over a 1 week period. In the first week, subjects will be blind-randomized into either the acetaminophen or placebo group. They will then undergo a test to determine their gait speed by performing two 25 foot walks at their best comfortable pace. The walks will be 1 minute apart. The average speed from those 2 walks will be obtained. Subjects will then take either the acetaminophen or the placebo. Following a 45 minute rest period they will then get on a treadmill and will walk at the previously determined speed for as long as they can. Walking will stop if the subject can no longer maintain the speed or if they wish to no longer continue. The subjects will wear a safety harness at all times during the walk to prevent falls. Heart rate and core body temperature will be measured via skin sensors. One week later the subjects will return and repeat the procedure but this time in the opposite condition. Subjects who took the acetaminophen will take the placebo and subjects who took the placebo will take the acetaminophen. The difference between distance walked in the 2 conditions will be compared.