Periodic Limb Movement Syndrome (PLMS) is involuntary and repetitive movement of the lower limbs that tends to occur after 20 – 30 seconds. The legs are affected in most of the patients. However, the limbs of the upper body can also be affected. PLMS occurs periodically throughout the night but the severity varies from one night to another.
People with PLMS or those sleeping with such a person will notice muscle spasms that throw the legs upwards. These movements can last for a few minutes or even hours. PLMS does not discriminate between the genders. Though children can develop the condition, it is more common in people who are above the age of 65.
PLMS and Sleep
The muscle spasms are initially felt when the patient is trying to initiate sleep. In fact, achieving sleep when you have this condition is rather difficult and the patient end up spending hours before falling asleep. While the patient may at times not feel the muscle spasms, they may be woken up by the movements. Falling asleep after being woken up by the spasms is difficult.
It does not only affects the sleeping patterns of the patient. It also affects those sleeping partner. This is because the sleeping partner is kicked or the blanket may move awkwardly to an extent of being woken up.
- Restless Leg Syndrome (RSL) irritability or itchiness in legs that eases when the limbs are moved.
- Difficulty in falling asleep.
- Daytime sleepiness.
- Daytime moodiness.
- The movements typically start with the big toe and extend upwards to the rest of the legs.
PLMS patient will feel the burning or tingling sensation seen in RSL. RSL and Periodic Limb Movement Syndrome share similar symptoms but not everyone with PLMS has RSL. However, about 80% of all the patients who suffer from RLS will also be diagnosed with Periodic Limb Movement Syndrome.
As suggested earlier, the patients are usually not aware of the movements. In fact, in most of the cases the bed partner is more aware of the movements. The person finds that they take longer to fall asleep. At times, they make wake up in the middle of the night without knowing what woke them up since the spasms only last for few seconds.
PLMS usually occurs in the non-REM (Rapid Eye Movement) zone. Therefore, it becomes difficult to crossover to the REM part of the sleep cycle. The REM part of the sleep cycle is the deepest and most restful part of sleep. For this reason, the rest or refreshment expected after sleep is alien to these patients leading to daytime sleepiness and drowsiness.
Treatment and Coping Tips
The exact cause of PLMS is unknown. But just like RSL it is related to kidney disease, iron deficiency and pregnancy. The first step in treatment is to differentiate it from its cousin RLS. Treatment involves the use of dopamine antagonists to reduce the tremors. Benzodiazepines can also be used to control the spasms. Engaging in relaxing exercises such as yoga is helpful. A hot bath and massage before sleeping goes a long way in easing the episodic tremors.