Restless Legs Syndrome - RLS and Parkinson’s Disease (en Inglés) - Khosro Hekmat

The same treatment does not mean the same disease.

"My legs are restless at night - is that part of my Parkinson’s?" The question is common in Parkinson’s clinics and has no short answer. Both conditions improve with dopaminergic medication, and that has fuelled speculation about a connection for decades. This volume examines that idea finding by finding, because the answer decides which treatment helps.

About 20% of people with Parkinson’s disease meet the criteria for restless legs syndrome, according to a pooled analysis of 46 studies. Yet a large controlled study of 436 people with Parkinson’s disease and 401 matched controls found no significant difference in RLS: 3.4%, compared with 2.7%. What was clearly more common was leg restlessness that does not meet the full criteria: 12.8%, compared with 4.5%. Genetic analyses point the same way: within the limits of the studies, they found no shared genetic basis and no evidence of a causal relationship in either direction.

In the brain the two conditions differ at exactly the place where one would expect them to agree. In RLS, brain iron tends to be low, although the findings for the substantia nigra are not uniform. In Parkinson’s disease it is increased there. Dopamine transporter imaging is markedly reduced in early Parkinson’s disease and was normal in RLS in the direct comparison cited here. The book also explains why German claims data link an earlier RLS diagnosis with later Parkinson’s disease, and why a large longitudinal study of 1,280 people with REM sleep behaviour disorder found that RLS was not a significant predictor.

The practical core separates five causes of restless legs at night: wearing off of the medication, night-time immobility, restless legs syndrome, periodic limb movements in sleep and REM sleep behaviour disorder. One question is a useful guide: can you move your legs easily, or do you feel you have to move them? Augmentation, a treatment-related worsening, affected 22 of 30 people with RLS on levodopa in the first systematic study. Whether it also develops in people with Parkinson’s disease has not been investigated.

Treatment starts with iron, with a ferritin concentration at or below 100 µg/l as the threshold for discussing iron treatment and transferrin saturation always measured as well, and goes on to the alpha-2-delta ligands. The book states openly that no controlled drug trial of RLS treatment in people with Parkinson’s disease was found. It also covers deep brain stimulation (two studies without a control group) and ends with an action plan and four questions for the consultation.

WHAT IS IN THE BOOK

- Where the idea of a connection comes from, and the reasoning error it may involve

- Iron, substantia nigra and dopamine transporter: what the images show

- Why the frequency figures range from 3.4% to 40%

- The leg restlessness without a name

- RLS as an early sign: claims data against the longitudinal study

- What genetic studies show, including one gene region with opposite effects

- Five night-time causes of restless legs, and how to tell them apart

- Akathisia, wearing off and drugs that can induce or worsen RLS

- Iron in Parkinson’s disease: the finding that challenges the hypothesis

- Alpha-2-delta ligands, opioids and the rotigotine patch

- Augmentation and impulse control disorders

- Deep brain stimulation, and your own plan for the medical consultation

WHO THIS BOOK IS FOR

For people with Parkinson’s disease whose legs will not keep still at night, for partners who share those nights, and for health professionals.