Can Transcranial Direct Current Stimulation Improve Ambulation and Fatigue Resistance in People With MS?

Study Overview
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Brief Summary
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In this project the investigators will be using non-invasive brain stimulation on people with multiple sclerosis (PwMS) to improve leg muscle function. Two groups of participants will be recruited. One group will perform strength testing with and without the brain stimulation. The second group of participants will perform a fatigue task, pulling against a wire at a low level of force, with and without the brain stimulation. This type of brain stimulation has been shown to transiently improve strength and fatigue measures in other populations, e.g. aged, Parkinson's, and improve cognitive abilities in people with multiple sclerosis. It is the investigator's hope that the increases in performance seen in other patient groups will also occur in people with multiple sclerosis. Future investigations will look to apply the non-invasive brain stimulation technique during physical rehabilitation to improve short and long term outcomes related to physical function.

Official Title
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Can Transcranial Direct Current Stimulation Improve Ambulation and Fatigue Resistance in People With MS?

Conditions
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Multiple Sclerosis

Intervention / Treatment
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* Device: tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Medically diagnosed with MS Moderate disability (Patient Determined Disease Steps score 2-6) Self-reported differences in function between the legs (2-5 on a 1-5 scale) People with MS with physician clearance Exclusion Criteria: A relapse of disease symptoms in the last 60 days A condition unrelated to MS that would exacerbate fatigue, such as anemia, hypothyroidism, shiftwork-related fatigue, B12 deficiency, major sleep disorder, or major depressive disorder Medical diagnosis or condition that makes participating in exercise training dangerous, such as major renal, pulmonary, hepatic, cardiac, gastrointestinal, HIV, cancer (other than treated basal cell cancer), other neurological disorders, or pregnancy History of heart attack or current diagnosis of cardiovascular disease History of seizure disorders (or on medications known to lower seizure threshold), hydrocephalus (buildup of fluid in the brain), or diabetes Alcohol dependence or abuse (>2 drinks/day), or present history (last six months) of drug abuse History of significant traumatic brain injury or hydrocephalus Pregnancy Recent hospitalization (within the last 3 months) or enforced bed rest/sedentary state. Presence of metal is present or implanted device or metal object that is not safe for TMS.

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sham first, wash out 7 days, then tDCS<br>Separated by a minimum of 7 days from the sham treatment in a counterbalance order, all participants will perform leg muscle strength and fatigue testing once with tDCS stimulation. Leg muscle strength testing will be measured by performing a series of maximal effort knee extension, knee flexion, plantar/dorsi-flexion trials. Sham: Less than 0V of Transcranial Direct Current Stimulation tDCS: Less than 10V of Transcranial Direct Current Stimulation | Device: tDCS<br>* Less than 10V of Transcranial Direct Current Stimulation. Sham 0V of Transcranial Direct Current Stimulation.<br>* Other names: The Brian Simulator;|
| Experimental: tDCS first, wash out 7 days, then Sham<br>Separated by a minimum of 7 days from the sham treatment in a counterbalance order, all participants will perform leg muscle strength and fatigue testing once with tDCS stimulation. Leg muscle strength testing will be measured by performing a series of maximal effort knee extension, knee flexion, plantar/dorsi-flexion trials. Sham: Less than 0V of Transcranial Direct Current Stimulation tDCS: Less than 10V of Transcranial Direct Current Stimulation | Device: tDCS<br>* Less than 10V of Transcranial Direct Current Stimulation. Sham 0V of Transcranial Direct Current Stimulation.<br>* Other names: The Brian Simulator;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Leg Muscle Strength With and Without tDCS. | Knee extensor strength will be tested with tDCS (less than 10V) and sham stimulation (0V). Participants performed maximal voluntary contractions (MVCs) with the knee extensors to objectively determine the weaker leg as more-affected, which was afterwards confirmed by the subject's self-report and used for the subsequent endurance task. This task consisted of a sustained isometric contraction at 15% MVC until volitional task termination and was immediately followed by a post MVC. During tDCS, stimulation intensity was ramped up to 2 mA, started 90 second prior to the task, and extended until task failure or a maximum stimulation length of 20 minutes. For Sham, the current was ramped up to 2 mA, but turned off after 30 seconds. | At session 1 and minimum of 7 days later | 
| Leg Muscle Endurance With and Without tDCS. | Knee extensor endurance (fatigue) will be tested with tDCS (less than 10V) and sham stimulation (0V), as reported as time to failure. During tDCS, stimulation intensity was ramped up to 2 mA, started 90 second prior to the task, and extended until task failure or a maximum stimulation length of 20 minutes. For Sham, the current was ramped up to 2 mA, but turned off after 30 seconds. | At session 1 and minimum of 7 days later. | 
| 6 Minute Walk Test | After completion of the tDCS/Sham strength assessment participants will perform a 6 minute walk test. The test will be performed in a cordoned off hallway with 2 cones placed 30 meters apart. Once the participants begin walking, a timer will be started and the distance covered every min will be recorded. Participants are allowed to stop and rest during the test if required. Every minute during the walk test participants will be asked their rating of perceived exertion (RPE, 0-10 scale). | At session 1 and minimum of 7 days later |