Tell Me More about the Symptoms of Multiple Sclerosis

The most common symptoms of MS are postural and balance problems, gait (walking) and movement difficulties, spasticity, and fatigue. These symptoms reduce independence, increase the risk of falls, and decrease the quality of life.

MS results in these symptoms because it is a disease that affects the nervous system controlling the muscles. Nerve fibers in the brain and body are usually surrounded by a protective sheath, known as the myelin sheath. In MS, the body’s immune system damages this sheath, or the cells that produce and maintain it. When the sheath is damaged, messages cannot be passed along the nerves, hence leading to muscle control problems. The term sclerosis means scarring, because multiple areas of scarring form where the nerve sheath has been damaged.

What Is Spasticity?

Spasticity is a term used to describe muscles that have high tone (are tight) or are contracted. It can affect the postural and limb muscles as well as speaking and eating muscles. It is not possible for a person to voluntarily control spasticity, as it is caused by problems with the brain and nerves that control the muscles. Normal muscle control means that we can voluntarily and involuntarily tighten and relax our muscles to move our body. But muscles with spasticity cannot be fully relaxed, meaning that a person cannot move their body in a typical way, if at all. The exact level of spasticity can vary, depending on other factors. Severe spasticity can be painful, energy-consuming, and result in permanent problems with joint stiffness and muscle weakness.

How Is Spasticity Treated?

There is evidence that the MS damage to the nerve pathways leads to spasticity. Specifically, damage to a pathway known as the corticospinal tract can lead to hyper-excitability of the messages that tell muscles to contract, and thus to spasticity. There are devices that can control – or modulate – this neuro-excitability, called neuromodulators.

How Do Neuromodulators Work?

Neuromodulator devices are used for treatment of many different neurological conditions. They work by stimulating or activating the nerve cells in the brain with small amounts of electric signals. The signals are sent through electrodes placed on the skin from a battery-powered device. They can have a lasting effect, even after the device is switched off and the electrodes removed. In terms of treatment for MS, the authors of this paper were interested in two types of neuromodulators: transcranial direct-current stimulation (tDCS) and transcranial magnetic stimulation (TMS).

How Did the Authors Carry Out Their Research?

The authors carried out a systematic review and meta-analysis. They searched research databases for all research on MS and neuromodulators. There are international guidelines for how to do this in the best way: such as using key search words to find suitable papers and using logical processes to categorize the different types of research. The authors selected only the best and most relevant research, using international guidelines and statistical methods to compare the research. They ended up with sufficient information from seven studies.

What Were the Results of the Review and Analysis?

Of the final seven studies, four studies used the tDCS technique and three studies used the TMS technique.

With so few studies, the authors briefly described each study and stated that it was difficult to compare them due to their differing number of treatment sessions (i.e., one treatment session or multiple sessions). However, their statistical methods helped them to conclude the following:

• For impact on balance and gait (walking): A single session of tDCS technique neuromodulator treatment definitely does not help but multiple sessions of tDCS have led to lasting changes and improvements.
• For impact on spasticity: Multiple sessions of the TMS technique were helpful in decreasing spasticity.

Take-Home Message

With so few studies, the authors report that further studies are required before it is possible to have a definite result on the specific effects of neuromodulators and different neuromodulator treatment strategies. However, they remain hopeful: Where they identified that multiple treatment sessions can help, they believe that further studies on the use of multiple treatment sessions could only strengthen this conclusion.

Note: This post is based on an article that is not open-access; i.e., only the abstract is freely available.