Is Restless Leg Syndrome Related to Parkinson's Disease?
Both common neurological disorders, Restless Leg Syndrome (RLS) and Parkinson’s disease (PD) have caused a debate over whether they share a medical link.
What is Restless Leg Syndrome?
Restless Leg Syndrome (RLS) is a sleep and movement disorder. Those with this condition will have an urge to move their legs and abnormal feelings of tingling or prickling (also known at “pins and needles”). The urge to move will feel worse at rest, and only be relieved by movement such as stretching or walking. All of these symptoms will only occur or worsen at night. Some people with RLS will move their legs during their sleep as well. This is known as Periodic Limb Movement during Sleep (PLMS), and may cause so much movement they will wake themselves up.
What Causes Restless Leg Syndrome?
The causes of Restless Leg Syndrome are not known, but it is thought that RLS develops from dysfunction in the dopamine and iron systems within the brain. Medical conditions associated with the occurrence or RLS include:
- Renal (kidney) failure
- Iron deficiency
Is there a link between Restless Leg Syndrome and Parkinson's Disease?
Previous studies have suggested that there is a link between RLS and PD due to both conditions sharing the common feature of dysfunction in the part of the brain that produces dopamine. Another commonality between these two conditions is that they have been shown to run in the family. About half of the cases are in patients that have relatives with the disorder. Another argument for the medical linkage of these neurological disorders is that they share the same treatments - no other common disorder is treated with the same dopamine agents.
Even though earlier studies have shown a significant prevalence of RLS in patients with Parkinson’s, researchers have not been able to find a common patient demographic or Parkinson’s treatment to reliably predict the development of restless leg syndrome. Also through studies, they have found that though both conditions present dysfunction in the dopamine-producing neurons in the brain, the actual mechanisms, or how the neurons are affected, are not identical.
Earlier studies involved patients with advanced cases of Parkinson’s disease that have been taking dopamine drugs for years, which may account for the significance of RLS. The use of dopamine drugs makes it much harder to correctly diagnose restless leg syndrome. The dopamine can cause restlessness that may be confused with RLS.
Newer studies have looked at patients that were only recently diagnosed with PD and have not yet taken dopamine drugs. These more recent studies suggested that RLS is not significantly more common in PD patients than those without the disease, but Parkinson’s patients were almost three times more likely to have leg motor restlessness.
How is Restless Leg Syndrome Treated?
If you think you or your loved one may have restless leg syndrome, see your doctor or primary healthcare provider to confirm a diagnosis. Beyond the dopamine medications available, there are other simple lifestyle changes that can help RLS. These changes include:
- Iron supplements for those with iron deficiency
- Regular bedtime routine, getting up and going to bed at the same time each day
- Do not nap during the day
- Exercise during the day, but not close to bedtime
- Avoid caffeinated drinks or alcohol before bedtime
As science continues to investigate the causes of RLS and it's potential link to Parkinson's Disease, it's important to seek medical attention if you or a loved one are presenting symptoms. Catching most diseases early enough increases the likelihood that a treatment can be effective.