Effects of exercise rehabilitation on fatigue in multiple sclerosis

Multiple sclerosis (MS) is a chronic disease with heterogeneous symptomatology. Inactivity, functional impairments and fatigue are common consequences of MS. Fatigue is the most common symptom reported by MS patients; however, fatigue is a difficult construct to define, measure, and manage. This dissertation describes an investigation designed to (1) measure physiologic function, functional performance, and fatigue across multiple domains in MS patients over a simulated day and a half of work, and (2) assess the effectiveness of three resistance exercise rehabilitation programs compared with MS and non-MS controls on improving function and fatigue. Ultimately, 73 MS patients and 20 age- and gender-matched controls participated in the study. The investigation was divided into four separate, yet related, steps in order to meet our two primary objectives. The background and results of each step are described in detail and constitute the main body of this dissertation: Construction of an Efficient and Informative Test-Battery for Fatigue in MS , Assessment of Workday Fatigue in Patients with Multiple Sclerosis, Randomized Controlled Trial of Anti-fatiguing Resistance Exercise for Individuals with Multiple Sclerosis, and The Relationship Between Objective Measures of Physical Capacity and Self-reported Ability in Patients with Multiple Sclerosis. Briefly, this study concludes that MS can affect any and all functional abilities. Many of the physical/functional deficits in MS may be due to secondary causes (e.g. inactivity) and are amenable to appropriate resistance exercise rehabilitation, especially supervised programs. Objective evidence of fatigue (decrease in performance over time) is difficult to observe in MS patients; i.e., they seem to pace themselves when confronted with physical tasks. Subjective (self-reported) fatigue, on the other hand, is highly variable over time in this population. Thus, self-report should not be discounted in MS. Perception influences behavior and, therefore, can provide insight into an individual's objective performances. Moreover, improvements in functional capacity can be observed without changing an individual's overall ratings of perceived fatigue. A key benefit of a structured resistance exercise rehabilitation program appears to be the ability to increase one's fatigue threshold or tolerance in MS.