Restless Leg Syndrome and Parkinson’s Disease

Restless Legs Syndrome (RLS) is a neurologic and sleep-related disorder that is characterized by an irresistible urge to move the legs. The symptoms respond to dopaminergic medications such as Levodopa, which is also used for the treatment of Parkinson’s disease (PD). It makes an interrelation between the two conditions. Here we explore RLS and its potential connections with PD.

Characteristics of RLS

  • The trademark of RLS is a feeling of restlessness that usually occurs in the legs. It is frequently along with an additional sensation such as tingling or electric sensations which are commonly found in the legs. The symptoms are usually not as in peripheral neuropathy, but rather often in the thighs or calves.
  • The restlessness is worse when the person is not moving or at rest. It makes it hard for people with RLS to get to sleep. It can also affect the capacity to sit still to relax or do desk work.
  • RLS symptoms usually are absent in the daytime and occur in the evening. This is the reason that RLS is considered a sleep disorder. If the symptoms are present in the daytime, the intensity of the sensations is usually less than in the evening.

Characteristics of PD

  • One of the most common movement disorders.
  • This is a progressive loss of muscle which leads to trembling of the head and limbs while at rest.
  • Parkinson’s disease also causes impaired balance, slowness, and stiffness.
  • This condition tends to worsen when a person is under stress or anxiety.

Using Dopaminergic Medication

RLS is treated well by medicines also used for the treatment of PD. Some aspect of brain dopamine function is likely changed in RLS. Conversely, unlike in PD, wherein the insufficiency in substantia nigra dopamine-producing cells can be verified in several ways, no such abnormality has shown in RLS.

Using dopaminergic medications for the treatment of RLS can be tricky. In several people, it might lead to an occurrence known as augmentation. Wherein, if dopaminergic medications are used for the long term, it can worsen the symptoms. As a result, the symptoms might appear earlier in the day or migrate to the upper body in addition to the legs.

Is RLS more common in PD?

RLS affects about 4-10% of the population and PD in about 1.5% of the elderly, there will be some coincidental overlap. However, people with PD might feel sensations the same as RLS when their dosage of dopamine medication diminishes gradually. Over the past years, there have been various studies on whether RLS is more common in PD than in the overall population. Different studies have come to different conclusions.

Some researchers explain that some people with PD do not have RLS but rather Leg Motor Restlessness (LMR).  

  • RLS is worse when the legs are not moving and temporarily relieved by movement.
  • LMR is not worse when the legs are not moving and are not relieved by movement.

Leg Motor Restlessness may be increased in people with PD, while exact RLS may not be.

Treatment of RLS in PD

Various people with PD have difficulty falling asleep because of annoying sensations in the legs along with an unbearable sense of restlessness in the legs. Taking dopamine agonists before bed may be helpful for these people. In some patients with PD, caution is needed especially in older or more advanced patients. Dopamine agonists might confuse and are thus not well-tolerated. Long-acting Levodopa medications can also be effective such as:

  • Gabapentin
  • Pregabalin
  • Gabapentin Enacarbil

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