Transcutaneous electrical nerve stimulation in persons with MS

Persons with multiple sclerosis (pwMS) often have an increased sense of
fatigue. Furthermore, they present walking difficulties which negatively
affects their mobility and results in an additional increase of fatigue.
Previous literature suggests that transcutaneous electrical nerve stimulation
(TENS) of leg muscles might increase their walking capacity and decrease
perception of fatigue. In the present study we aim to investigate whether TENS
of leg muscles in combination with strength training reduces walking
difficulties and sense of fatigue in pwMS in comparison with only TENS, only a
short strength training protocol or no training. A similar aim is addressed
after TENS and strength training of elbow flexor muscles.

Primary Objective:
What is the effect of a four-weeks combined TENS and exercise program, in
comparison with no training, an exercise program or TENS only program, on the
walking capability, perceived walking disability, and sense of fatigue of pwMS.

Additional Objective:
What are the associations between the changes in the walking capability,
perceived walking disability, sense of fatigue, and changes in muscle force and
effort.

What is the effect of a four-weeks combined TENS and exercise program, in
comparison with no training, an exercise program or TENS only program, on the
psychomotor speed?

The study design is a mono-centre intervention study. Subjects will undergo
transcutaneous electrical nerve stimulation (TENS), strength exercises
(SExerc), both TENS and SExerc (COMB) simultaneously, or sham stimulation
without training (CON) of both leg and arm muscles. Walking, force, fatigue and
psychomotor speed measurements are performed before, directly after and three
weeks after the training sessions.

Group I: receives no intervention, only sham TENS (CON), Group II: performs
strength exercises (SExerc), Group III: receives TENS while at rest (TENS) and
Group IV: receives TENS while performing strength exercises (COMB). The
training consists of 3 training sessions of 10 minutes per muscle group (arm
and leg) per week for four weeks.

There are no risks involved in the measurements nor the training protocol.
Recent experiments have shown that exercise is safe and beneficial for persons
with MS. TENS consists of a stimulation protocol with low intensities which
makes the stimulation non-painful. Similar stimulation protocols are used
therapeutically to reduce chronic pain. There is a small chance that in
subjects which are prone to have spasms that the stimulation could evoke
spasms, although TENS is also used to counteract spasms. Some patients
experience mild autonomic responses and minor skin irritation beneath
electrodes. The time investment for the subject is 4 measurements of 1 hour
(total 4 hours), 3 times filling out questionnaires of up to 50 minutes (total
1.5 hours) and 12 training sessions of 10 minutes per muscle (in total 4
hours).