Restless legs syndrome

Restless legs syndrome (RLS) is not rare but is rarely diagnosed by clinicians. Articles published in this and recent issues of Neurology reflect the growing interest in this area, fueled by new findings from pharmacologic, electrophysiologic, and neuroimaging studies. Despite a lucid description over 50 years ago by Ekbom,1 there is considerable misconception about RLS. Persons with RLS, even when their symptoms are quite troublesome or disabling, often do not seek medical attention, or the symptoms are wrongly attributed by physicians to nervousness, insomnia, stress, muscle cramps, arthritis, or a simple consequence of aging. Although no medical specialty has claimed rights of ownership to RLS, the correct diagnosis is usually made by neurologists, movement disorder experts, and sleep specialists.

The poor recognition and frequent misdiagnosis have hampered epidemiologic studies in RLS. Estimated prevalence rates vary widely, from 1% to 15%, but the true prevalence is probably close to 5% in the general population and considerably higher in the elderly. One study of 133 patients with typical RLS found the mean age at onset to be 27.2 years and the presence of RLS in at least one first-degree relative in 63% of cases.2 Future epidemiologic studies will be aided by the diagnostic criteria formulated by the International Restless Legs Syndrome Study Group (IRLSSG).3 The minimal criteria include the following: 1) an intense, irresistible urge to move the legs, usually associated with sensory complaints (paresthesia or dysesthesia); 2) motor restlessness; 3) worsening of symptoms at rest and relief with motor activation; and 4) increased severity in the evening or at night. Periodic limb movements in sleep (PLMS), detected by an overnight sleep study and present in at least 80% of patients with RLS, is the only laboratory abnormality typically associated with RLS. There is, however, night-to-night variability, which makes …