Multiple Sclerosis and Spasticity

What Causes Spasticity?

Within the body’s central nervous system there is a complex interactive process that controls the contraction and relaxation of muscles. Nerve pathways direct messages between the brain and muscles to produce the movement that you want.

For example, when we make a fist, there is simultaneously:

• A ‘go’ message to the relevant muscles to curl the fingers.
• A ‘stop’ message to the muscles that keep the fingers straight to relax.
• A co-ordinating network that ensures the movement is smooth and sustained.

However, MS damages the nervous system and this interferes with the coordination or movement of muscles, particularly with getting them to relax.

Muscles affected by spasticity generally feel stiff or cramped, and can lock a joint into position until the muscle tension is reduced by fatigue or by stretch techniques. (See page 9 for more information on stretching).

The level of spasticity may vary from a mild increase in muscle stiffness (which can be relatively easy to control), to sudden strong spasms that contract muscles in rigid positions (which can be difficult to overcome).

The strength of the reaction can depend on the damage to the central nervous system, i.e. the severity of the MS. The more nerve fibres that are affected, the more easily triggered and harder to overcome spasticity becomes.

Aside from the neurological damage, other common causes of a spastic reaction for people with MS are:

• A pain message from injury or joint inflammation, or aching from poor posture;
• Limb contact against an immovable object, triggering a spastic reaction to relieve the pressure;v
• Overfull bladder or bowel, or constipation;
• Infections (e.g. bladder infection or ‘flu’);
• Sudden movement or stretch to affected muscles (e.g. quick aerobic exercises or being startled);
• Extremes of temperature;
• Increased skin sensitivity;
• Specific muscle actions or positions which produce a pattern of reaction (the next section discusses these);
• Increases in level of stress chemicals, e.g. adrenalin.

The next few sections suggest some approaches for preventing and managing spasticity, and they can be used regardless of how the reactions were caused.