Spasticity is a symptom of multiple sclerosis (MS) that causes involuntary muscle stiffness and spasms. MS occurs when the body’s immune system mistakenly attacks the myelin sheath, which is the protective covering around nerve cells.
About 60–84%Trusted Source of people living with MS experience spasticity, which affects individuals to varying degrees. It can range from being a minor annoyance to causing issues that have a significant effect on daily living and quality of life. It can manifest as muscle spasms, tightness, and pain, which influence how someone performs daily tasks.
MS develops because the immune system damages myelin, which is responsible for protecting the nerves. This damage prevents the nerves from relaying signals correctly.
This article looks at MS spasticity in more detail, including its causes and treatments.
What is spasticity?
Spasticity is a common symptom of MS. It refers to muscle stiffness and involuntary muscle spasms, including pronounced contractions and sudden, uncontrollable movements. Spasticity varies in its severity. Some individuals experience minor muscle tightness that has little effect on daily living. However, others may have severe spasticity that causes uncontrollable spasms of the limbs and limits the ability to walk or move objects. Uncontrollable spasms can also cause pain in and around the joints and spine.
Flexor spasticity tightens the limbs in a bent position to the extent that someone cannot straighten them. However, extensor spasticity causes the limbs to straighten and prevents an individual from bending them.
What does it feel like?
For some individuals, spasticity can cause pain and a sensation of muscle tightness. However, the signs and symptoms are highly variable and may include:
- reduced range of motion
- difficulty relaxing or releasing the muscles
- clonus, which is a repetitive movement of a hand or foot
- increased deep tendon reflexes
A person can experience powerful spasms that cause their legs and arms to jerk with significant force or fix in uncomfortable positions.
Muscle spasms and stiffness can cause pain ranging from dull aches to sharp, unbearable pain. These symptoms can also interfere with good posture, leading to back pain and other discomforts.
Stiffness can sometimes have a positive effect. For example, it can help someone with weak leg muscles walk and stand.
What causes it?
Spasticity in MS occurs because of damage to the myelin covering nerves that control movement. This damage causes nerve impulses to slow down or stop, resulting in neurological problems.
MS is an autoimmune disease in which the immune system mistakenly attacks the myelin sheath or the cells responsible for producing and maintaining it. This attack leads to inflammation and damages both the myelin sheath and, eventually, the nerves that it surrounds.
The word sclerosis refers to the multiple areas of scarring on the nerves and their myelin sheaths in MS.
Environmental factors, such as extreme temperatures, humidity, or tight clothing, can sometimes trigger spasticity in people with MS. Additionally, some people may find that changing position, sudden movements, or infections can worsen spasticity.
Is spasticity the same as a spasm?
Spasticity and spasms are both symptoms of MS that can affect an individual’s quality of life.