Restless Legs Syndrome

Melody Ryan; John T. Slevin

Am J Health Syst Pharm. 2006;63(17):1599-1612.

Epidemiology

Except perhaps in Asian populations, RLS is a common disorder, occurring in about 10% of the population. The age-adjusted prevalence of RLS determined by telephone interviews in a random population of 1803 adults in Kentucky was 10%.^[12] A Canadian survey of 2019 adults estimated the prevalence of RLS symptoms at 17% for women and 13% for men.^[13] A population-based survey in West Pomerania, Germany, of 4107 subjects found an overall 10.6% prevalence.^[14] Using standardized questions in face-to-face interviews, Rothdach et al.^[15] reported an overall prevalence of 9.8% in 369 participants ages 65-83 years in Augsburg, Germany. In a study from Japan, 4612 participants living in urban residential areas were assessed for a single symptom of RLS by a self-administered questionnaire of the following two items: (1) Have you ever been told you jerk your legs or kick sometimes and (2) have you ever experienced sleep disturbance due to a creeping sensation or hot feeling in your legs?^[16] The prevalence of RLS ranged from 3% in women ages 20-29 years to 7% in women ages 50-59 years and correlated with age. In contrast to the first three studies, RLS had a higher prevalence in men than women, with the difference reaching significance in those 40-49 years old; in men there was no positive correlation with age. Face-to-face interviews of 157 consecutive individuals ages 55 years and older participating in a health screening program and 1000 consecutive individuals ages 21 years and older from a primary health care center in Singapore yielded much lower prevalence data.^[17] Using IRLSSG criteria, the prevalence of RLS in this predominantly Asian population was 0.6% in the older (1 male) and 0.1% (1 female) in the younger cohorts. In the Kentucky and Singapore studies, there was no gender difference; however, in the two German studies, the prevalence was higher in women and in the Japanese study it was higher in men. The Canadian study reported a significantly higher occurrence of bedtime leg restlessness in women.

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Cite this: Restless Legs Syndrome - Medscape - Sep 01, 2006.

Table 1. Common Dosages of Medications Used To Treat Restless Legs Syndrome ^{[68,69,70,71,72,73,74,75,76,77,78,79,80,85,86,87,88,89,103,104,105,109,110,112,113,114,115,116,120,121,122,123]}
Medication	Starting Dosage (mg/day)	Final Dosage (mg/day)
Oral iron replacement^a
Ferrous sulfate	975	Not applicable
Ferrous gluconate	1950	Not applicable
Ferrous fumarate	600	Not applicable
Dopaminergic agents
Carbidopa or benserazide with	25	50
levodopa	100	200
Ropinirole^b	0.25	1.5-2
Pergolide^c	0.05	0.35-0.5
Pramipexole dihydrochloride	0.375	0.5-1.50
Anticonvulsants
Gabapentin	100-300	200-900
Carbamazepine	200	200-400
Benzodiazepines
Clonazepam	1	1

^aListed salts supply approximately 200 mg of elemental iron daily.
^bAs the hydrochloride salt.
^cAs the mesylate salt.

Appendix B: Evaluation methods used in restless legs syndrome studies

Rating scales

The Clinician Global Impression-Improvement scale is a rating system in which the clinician assigns a score from 1 (very much improved) to 7 (very much worse). It is not specific to restless legs syndrome (RLS).
The International Restless Legs Syndrome scale is a 10-item scale with scores ranging from 0 (best) to 40 (worst). Items assess the intensity and frequency of the primary features of RLS, associated sleep problems, and the impact of RLS on mood and daily functioning. Patients' RLS can be classified as mild (1-10), moderate (11-20), severe (21-30), or very severe (31-40).^[8]
The Medical Outcomes Study Sleep Scale has been validated in the general population but is not specific to RLS. Patients self-rate sleep disturbance, sleep adequacy, daytime somnolence, sleep quantity, respiratory impairments, and snoring. The score on each item ranges from 0 to 100.^[9]
The Pittsburgh Sleep Quality Index is a 19-item questionnaire to assess sleep quality and sleep disturbances. Patients score between 0 (best) and 21 (worst).
The Restless Legs Syndrome Quality of Life questionnaire is a validated 18-item questionnaire. Ten items are used to calculate an overall life impact score ranging from 0 (lowest quality of life) to 100 (best quality of life). The remaining items assess employment, work, and sexual interest.^[10]
The Short Form-36 is a well-validated, 36-item questionnaire. Quality of life is assessed in the domains of physical function, social function, role disturbances resulting from physical and emotional problems, mental health, energy and vitality, pain, and general health perception. It is not specific to RLS.
Sleep diaries are used daily to document the time the patient sleeps and subjective sleep quality.
The Standardized Sleep Inventory Schlaf-Fragebogen, part A, is a 22-item questionnaire that assesses sleep patterns and mood.

Clinical tests

Actigraphy is a method of counting movements during sleep. An activity meter is placed around the ankle. While not as detailed as polysomnography, actigraphy can be performed in the patient's home and is more economical.
Polysomnography is almost always performed in a sleep laboratory. Electroencephalography, surface electromyography (EMG), and video recordings of sleep are performed over one or more nights. From these data, a number of criteria can be derived: the total number of periodic limb movements of sleep (PLMS), PLMS index (number of PLMS per hour), PLMS arousal index (number of PLMS associated with arousal per hour), total number of arousals, sleep efficiency, and sleep latency (time for an individual to go to sleep).^[8]
The suggested immobilization test assesses RLS symptoms while the patient is awake. EMG surface electrodes are placed on the legs, and the patient is instructed to sit on the bed with eyes open and legs outstretched without moving. The patient indicates RLS sensations during the test.^[8]

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Restless Legs Syndrome

Epidemiology

Tables

References

Authors and Disclosures

Authors and Disclosures

Appendix

Appendix A: Diagnostic criteria for restless legs syndrome

Appendix

Appendix B: Evaluation methods used in restless legs syndrome studies

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