Correlation Found Between Restless Legs Syndrome and Multiple Sclerosis

Kathleen Louden

June 26, 2008

June 26, 2008 (Chicago, Illinois) — Patients with multiple sclerosis (MS) have more than 5 times the risk of having restless legs syndrome (RLS) compared with a healthy population, a new study shows.

In a population of 202 consecutive patients with MS, the prevalence of diagnosed RLS was 14.6%, according to a late-breaking poster presented here at the Movement Disorder Society's 12th International Congress of Parkinson's Disease and Movement Disorders.

Among 212 healthy control subjects who were matched for sex and age, the prevalence was 2.8%. The risk of RLS was significantly higher for patients with MS than for controls (odds ratio, 5.76; P = .00002), the authors reported.

The data confirm the results of previous studies that have reported an association between RLS and MS, the researchers conclude.

In a news release from the society, primary author Giovanni Cossu, MD, from the General Hospital S. Michele AOB G. Brotzu, in Cagliari, Italy, said, "RLS [is] a phenomenon frequently observed in MS. Future studies, already in progress and oriented to establish a more accurate correlation between RLS phenomena and neurophysiological and [magnetic resonance imaging] MRI data of MS patients, may allow [us] to definitively include RLS as an integral symptom of MS."

 

Methods

All patients (135 females and 67 males) completed a structured questionnaire according to criteria of the International Restless Legs Syndrome Study Group (IRLSSG) (Allen RP et al. Sleep Med. 2003;4:101-119). Of the patients, 91 (45%) responded that they had symptoms of the syndrome. Patients who fulfilled the 4 criteria by their self-reports were examined by a neurologist to verify the presence of RLS. Of these patients, 29 received a diagnosis of RLS. Only 6 of the 212 controls had RLS.

The 4 IRLSSG diagnostic criteria are as follows:

  • An urge to move the legs, usually accompanied or caused by uncomfortable and unpleasant sensations in the legs. Sometimes the urge to move is present without the uncomfortable sensations. Sometimes the arms or other body parts are involved in addition to the legs.

  • The urge to move or unpleasant sensations begin or worsen during periods of rest or inactivity, such as lying down or sitting.

  • The urge to move or unpleasant sensations are partially or totally relieved by movement, such as walking or stretching, at least as long as the activity continues.

  • The urge to move or unpleasant sensations are worse in the evening or night than during the day or occur only in the evening or night. When symptoms are very severe, the worsening at night may not be noticeable but must have been previously present.



Confirmation Needed

The current findings are important, but the study's use of a questionnaire to determine RLS symptoms creates a selection bias, said the chair of the Congress Scientific Program Committee, Serge Przedborski, MD, PhD, professor of neurology and pathology at Columbia University, in New York, in an interview.

"This is interesting, but the result needs to be confirmed before I say anything to my patients with MS," Dr. Przedborski told Medscape Neurology & Neurosurgery.

Boehringer Ingelheim provided a grant for this study. No information about potential conflict of interests was available for Dr. Cossu. Dr. Przedborski reported no relevant financial disclosures.

12th International Congress of Parkinson's Disease and Movement Disorders: Abstract LB6. Presented June 25, 2008.

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