People with multiple sclerosis are about twice as likely to develop restless legs syndrome compared to those without the disease, according to a study published in the Journal of Neurology by researchers in Spain.
The findings, reported this week, add to growing evidence that the neurological damage caused by multiple sclerosis extends beyond its well-known effects on movement and cognition, reaching into the pathways that regulate sleep and sensory processing.
What the Study Found
A team of Spanish researchers evaluated 440 multiple sclerosis patients treated at their hospital alongside 241 individuals without the disease, matched by age and sex. Every potential case of restless legs syndrome was confirmed by sleep disorders specialists, adding a layer of diagnostic rigor that many previous studies lacked.
The results showed that MS patients were approximately twice as likely to meet the diagnostic criteria for restless legs syndrome. Among MS patients, two factors were associated with even higher risk:
- Family history of RLS: Patients with relatives who had restless legs syndrome were more likely to develop the condition themselves
- Pyramidal symptoms: Those with problems related to voluntary movement—such as muscle weakness, stiffness, and exaggerated reflexes—had a significantly higher likelihood of RLS
The pyramidal tract is a major nerve pathway that runs from the brain through the spinal cord and controls voluntary muscle movement. In multiple sclerosis, immune-mediated damage to the myelin sheath that insulates these nerve fibers can disrupt signaling along this pathway.
The Overlap Between MS and Sleep Disorders
Multiple sclerosis is already known to cause significant fatigue, which is one of the most common and disabling symptoms of the disease. But this fatigue is often attributed to the disease itself or to the medications used to treat it, potentially masking underlying sleep disorders like restless legs syndrome.
RLS causes an irresistible urge to move the legs, usually accompanied by uncomfortable sensations described as crawling, tingling, or aching. Symptoms typically worsen during periods of rest or inactivity, particularly in the evening and at night, making it difficult to fall asleep or stay asleep.
These findings highlight the importance of routine assessment for RLS in MS patients, particularly in those presenting with sleep disturbances or motor impairment linked to pyramidal involvement.
When restless legs syndrome goes undiagnosed in MS patients, the resulting sleep disruption can worsen fatigue, cognitive difficulties, and overall quality of life—symptoms that may be incorrectly attributed solely to multiple sclerosis.
Why This Matters for Treatment
Identifying restless legs syndrome in MS patients is important because the condition is treatable. Following updated guidelines from the American Academy of Sleep Medicine, first-line treatments now include iron supplementation and alpha-2-delta ligand medications like gabapentin, gabapentin enacarbil, and pregabalin.
Notably, the guidelines moved away from recommending dopamine agonists, which were previously the standard treatment for RLS. These medications carry a risk of augmentation—a paradoxical worsening of symptoms with long-term use—that makes them particularly problematic for patients who already face a complex medication regimen for MS.
For MS patients with RLS, checking iron levels is an important first step. Iron deficiency is common in restless legs syndrome and is also more prevalent in people with chronic inflammatory conditions like multiple sclerosis. Correcting low iron stores can sometimes resolve or significantly improve RLS symptoms without additional medication.
What Patients Should Know
If you have multiple sclerosis and experience any of the following, it may be worth discussing restless legs syndrome with your neurologist or a sleep specialist:
- An urge to move your legs that worsens when you are resting or lying down
- Uncomfortable sensations in your legs described as crawling, pulling, or tingling
- Symptoms that are worse in the evening or at night
- Difficulty falling asleep or staying asleep beyond what you would attribute to your MS
- Temporary relief from movement such as walking or stretching
The researchers emphasized that routine screening for RLS should become standard practice in MS care, as early identification and treatment can meaningfully improve sleep quality and daily functioning for patients already managing a challenging disease.
