Fatigue in MS is related to sympathetic vasomotor dysfunction

The authors studied standard autonomic function tests and measures of heart rate variability in 60 patients with multiple sclerosis (MS) and correlated results with the Fatigue Severity Scale and the Modified Fatigue Impact Scale. The authors found that autonomic responses correlated with fatigue resembling a hypoadrenergic orthostatic response, possibly due to a sympathetic vasomotor lesion with intact vagal heart control. Treatments to control sympathetic dysfunction for MS-associated fatigue deserve further study.