Nearly 1 million individuals in the United States have multiple sclerosis, which causes fatigue and problems with walking. Fatigue and walking problems are poorly treated, but exercise training, particularly high-intensity walking exercise, may help. This provide insight into whether high-intensity walking exercise can improve fatigue and walking problems in people with multiple sclerosis, which could improve quality of life and reduce economic burden.
Multiple sclerosis (MS) is an immune-mediated, neurodegenerative disease of the central nervous system with a prevalence of nearly 1 million adults in the US. The pathophysiology of this disease results in two of the hallmark features of MS, namely symptomatic fatigue and walking impairment. These two features of MS are inter-related as symptomatic fatigue is often a driver of declines in walking and worsening of disability over time, and both compromise quality of life and independence. To date, fatigue and walking impairment are poorly managed through conventional disease modifying medications or rehabilitation therapy in MS. One approach for improving fatigue and walking in MS is an appropriate dose of exercise training. Current recommendations of 30 min/day 2 days/week of low to moderate exercise training can improve symptomatic fatigue, aerobic capacity, strength, and walking endurance, and other symptoms in people with MS. This prescription is often delivered using moderate-intensity, continuous training (MCT) walking. However, improvements in fatigue and walking outcomes have been small, suggesting that MCT may not be the optimal approach. In people with stroke, high intensity, interval-based walking exercise has provided a greater stimulus than MCT for improving outcomes, but this approach has not been researched in MS. There are a few field-wide limitations of research on exercise training, fatigue, and walking outcomes in MS. Often, researchers have (a) enrolled people with MS regardless of symptomatic fatigue and/or walking dysfunction, and this yields floor effects in outcomes and prevents conclusions on exercise as a treatment approach; (b) included people with mild disability, but not moderate or severe disability; and (c) applied exercise modalities not based on the principle of specificity (i.e., using walking training to improve fatigue and walking impairment). This project overcomes these field-wide limitations and compares effects of moderate and high intensity treadmill training on symptomatic fatigue and walking in people with MS with elevated fatigue and walking dysfunction.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
20
Participants will undergo 12 sessions (4 weeks, 3 sessions/week) of treadmill training. During each session, participants will walk for 40 min. with 5 min. of warmup and cooldown at 50% of maximal walking speed (tested each week) with 30 min. of training interposed. The type of training will be determined by the assigned treatment arm.
University of Illinois Chicago
Chicago, Illinois, United States
RECRUITINGSymptomatic fatigue
Change in symptomatic fatigue from pre to post training. Assessed by the Fatigue Severity Scale (FSS); scores range between 1 (min) and 7 (max), higher scores reflect greater fatigue severity.
Time frame: Immediately (within 1 week) before and after training
Walking speed
Change in walking speed will be measured with the 10-m walk test. This will be quantified as the average of 3 trials a comfortable and maximal speeds. Higher values represent faster walking speeds
Time frame: Immediately (within 1 week) before and after training
Corticomotor excitability
Transcranial magnetic stimulation (TMS) will be used to measure change in contralateral and ipsilateral corticomotor excitability of the paretic tibialis anterior. TMS will be applied at different intensities, and the response (motor evoked potential) is measured in the paretic TMS. Corticomotor excitability will be measured as the slope of the input output curve (intensity vs. response). Higher values represent greater corticomotor excitability.
Time frame: Immediately (within 1 week) before and after training
Fatigue impact
Change in the impact of fatigue on physical, cognitive, and psychosocial functioning will be measured from pre to post training. Assessed with the Modified Fatigue Impact Scale (MFIS); scores range between 0 (min) and 84 (max), higher scores reflect greater impact of fatigue.
Time frame: Immediately (within 1 week) before and after training
Walking endurance
Change in walking endurance will be assessed as the distance covered during the 6-minute walk test (6mWT). Higher values represent greater walking endurance.
Time frame: Immediately (within 1 week) before and after training
Aerobic capacity
Cardiopulmonary exercise tests will be performed on a motorized treadmill following an individualized protocol using standard procedures. Measures relating to peak oxygen consumption (VO2 max) will be calculated to quantify aerobic capacity. Higher values represent greater aerobic capacity.
Time frame: Immediately (within 1 week) before and after training
Visual processing speed
Assessed by the Symbol Digit Modalities Test (SDMT). Participants will verbally identify digit-symbol pairings as quickly as possible in response to a series of unpaired symbols displayed on screen. The outcome is the total number of correct responses in 30, 60 and 90 seconds. Higher scores represent greater visual processing speed.
Time frame: Immediately (within 1 week) before and after training
Verbal learning and memory
Assessed by the California Verbal Learning Test II (CVLT-II). Participants will be read aloud 16 words and immediately recall as many words as possible, in any order, for each of the five trials. The total score out of 80 will be calculated by summing the number of correct responses from each trial (T1 to T5). Higher scores represent greater verbal learning and memory.
Time frame: Immediately (within 1 week) before and after training
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