The objective of the randomized, sham-controlled trial will be to evaluate the effectiveness of treatment with transcutaneous electrical nerve stimulation (TENS) at reducing the level of fatigue experienced by people with MS.

We will compare the changes in self-reported levels of fatigue (symptom intensity) and measures of fatigability (work capacity) from before to after a 6-week intervention. Participants (18-65 yrs) will be randomly assigned to one of two groups: one group will receive an effective dose of TENS and the other group (control) will be given a sham dose of TENS. The treatment will be applied during 18 sessions (3x/week for 6 weeks) and delivered through electrodes placed on the skin overlying the dorsiflexor (tibialis anterior) and hip flexor (rectus femoris) muscles of both legs. Participants will be evaluated before (Week 0), during (Week 4), and after (Weeks 7 and 11) the 6-week intervention.

Our long-term goal is to develop strategies that can reduce the impact of fatigue on the daily activities of persons with MS. The objective of the randomized, sham-controlled trial will be to evaluate the effectiveness of treatment with TENS at reducing the level of fatigue experienced by people with MS. Our central hypothesis is that treatment with TENS applied to selected leg muscles in people with MS will produce superior improvements in self-reported and measured levels of fatigue and fatigability compared with a sham dose of TENS.

Inclusion Criteria:

• Men and women18-65 yrs
• Able to read, understand, and speak English to ensure safe participation in the project
• Clinical diagnosis of relapsing-remitting MS
• Self-reported difficulty with walking
• On stable doses of Ampyra, provigil, or other symptomatic-treating medications
• No relapse or systemic steroids within the last 30 days
• Able to arrange transportation to the Boulder campus

Exclusion Criteria:

• Vision or hearing problems that have not been corrected
• Problems with sensations to temperature, pressure, or pain
• Any arm or leg problems that would influence the ability to hold a weight
• Surgery to the arms or legs that continues to bother the participant
• Metal implants
• Medical diagnosis or condition that is considered to be an absolute or relative contraindication to participating in exercise training, such as major renal, pulmonary, hepatic, cardiac, gastrointestinal, HIV, cancer (other than treated basal cell cancer), other neurological disorders, or pregnancy
• History of head injury or stroke
• Taking antidepressants, anticholinergics, stimulants, sedatives, cannabis, illicit drugs or medications to treat herpes or neurologic pain.
• Diagnosis of diabetes mellitus
• Poorly controlled hypertension
• History of seizure disorders
• ≥2 alcoholic drinks/day, or present history (last 6 months) of drug abuse
• Spasticity that requires the individual to change intended activities more often than once a week
• Skin diseases or sensation problems in the legs or hands that influences some activities more often than once a week
• Inability to attend exercise sessions 3 days per week for 6 weeks