Restless legs syndrome (RLS) and periodic limb movement disorder frequently occur together. RLS is defined as unpleasant sensations of the limbs, usually the legs, relieved by movement. Patients have described crawling sensations, legs like lead pipes, itching, burning and involuntary movements. Periodic limb movement disorder is defined by brief twitches or muscle contractions that recur every 5 to 90 seconds, but most often, they occur at 30-second intervals. Patients with RLS complain about an inability to remain still in the evening, difficulty falling asleep and frequent awakenings during the night. Patients with periodic limb movement disorder often complain of daytime sleepiness.
In most cases of RLS, no specific cause can be identified. Approximately 30% of patients have a family history of the disorder. In some patients, RLS may be caused by damage to nerves, such as with sciatica, diabetes, polio or kidney failure. Iron deficiency anemia and vitamin deficiencies may cause RLS. RLS is thought become more prevalent with age, but children may also suffer from the syndrome. The cause of periodic limb movements during sleep is unknown.
Signs & Symptoms
Patients with RLS have complaints consistent with the disorder. These include irritating or painful sensations in the legs and involuntary movements. Often patients will complain of trouble falling asleep. Patients also complain of difficulty sitting still, and have trouble on long plane flights or at the opera (especially Wagnerian operas). Medications may trigger RLS symptoms. Consumption of caffeine, smoking, fatigue and hot temperatures may also worsen symptoms.
Overnight sleep studies are used to confirm the diagnosis of periodic limb movement disorder. Sensors are placed on the ankles or the large muscles at the front of the leg to record movements and muscle tension. The recordings are evaluated for the number of leg movements per night and their effect on sleep. Two indexes are calculated, one that represents the number of leg movements per hour of sleep with sleep disruption and one that represents the number of leg movements per hour without sleep disruption. RLS is diagnosed based on patient complaints. The decision to treat is frequently based on both the clinical picture and the results of the polysomnogram.
Medications are frequently very effective in controlling the symptoms of RLS and in reducing the number of limb movements during the night. Medications developed for the treatment of Parkinson's disease, such as Mirapex, are often used. A variety of other medications can provide relief, such as Neurontin, codeine, Tegretol, Klonopin and Sinemet.
The NorthShore University HealthSystem Sleep Disorders Program includes the Evanston Hospital Sleep Disorders Center, which is accredited by the American Academy of Sleep Medicine, and the Glenbrook Hospital Sleep Disorders Center. Physicians in the Department of Neurology serve as medical directors of the centers. Staff physicians include additional neurologists and a pulmonologist. All are experienced in the diagnosis and treatment of a broad variety of sleep disorders.
After a clinical evaluation including a detailed history and physical examination, most patients undergo a polysomnogram. Large, private bedrooms are available in both hospital laboratories for the test. State of the art monitoring equipment is used in both centers. Diplomates of the American Board of Sleep Medicine evaluate the polysomnograms. The results are discussed with the patient as well as their referring physician.