Undiagnosed individuals with first-degree relatives with restless legs syndrome have increased periodic limb movements.

BACKGROUND AND PURPOSE: To evaluate periodic limb movements during sleep (PLMS) in first-degree relatives of both restless legs syndrome (RLS) patients and matched controls without RLS in order to analyze patterns of this motor sign of RLS. PATIENTS AND METHODS: First-degree relatives of a consecutive case series of RLS patients and matched community controls without RLS were evaluated for diagnosis of primary RLS and for PLMS as determined by a leg activity meter. The data were analyzed to determine whether or not PLMS rates are higher than expected for RLS subjects in these families, who have mostly milder disease, and family members of early-onset RLS patients not themselves diagnosed with RLS. RESULTS: PLMS activity in family members was significantly higher for those diagnosed as RLS compared to those diagnosed as not-RLS. This difference was greater for older than younger subjects. In family members older than the median study age (52 years old) who were diagnosed as not-RLS, PLMS were significantly more frequent in those related to an early-onset RLS proband than in those related to either a control or late-onset RLS proband. CONCLUSIONS: PLMS are elevated even in those with mild RLS and reveal an age-related worsening of the motor component of RLS. PLMS may represent an incomplete expression of RLS tendencies in families of patients with early-onset RLS, but this needs to be confirmed in future longitudinal studies. The increase in PLMS with age, reported in healthy controls, may in fact occur in part as a partial expression of familial or genetic factors associated with RLS.

Evaluating the quality of life of patients with restless legs syndrome.

BACKGROUND: The primary morbidities of restless legs syndrome (RLS) involve sleep loss, extreme discomfort, and disruption of normal activities. Although the condition is not life-threatening, assessing the disease burden and the impact of RLS on quality of life (QOL) is critical for evaluating treatment benefits. OBJECTIVE: The purpose of this study was to assess the impact of RLS on QOL. METHODS: In this subanalysis of a specific validation study, the SF-36 (Medical Outcomes Study 36-Item Short Form health survey) was administered to 85 patients with primary RLS who had been referred to a sleep-medicine clinic. The scores were compared with published norms for the general population (N = 2474). RESULTS: The majority (63.5%) of RLS patients were women; the mean (SD) age was 62.4 (14.0) years; 67.1% of patients experienced RLS symptoms almost daily. The RLS group, particularly patients with more severe RLS, reported significant deficits (10-40 points on 100-points scales) in physical functioning, bodily pain, role functioning, mental health, general health, and vitality compared with the general population. The RLS sample had significantly lower scores (worse QOL) on all 8 scales of the SF-36 compared with patients with hypertension (P<0.01); compared with patients with other cardiovascular conditions (ie, congestive heart failure, myocardial infarction within the past year, and angina), the RLS group had lower scores on 6 of the 8 scales. RLS patients had lower scores on 7 of 8 scales compared with diabetes patients, and on 4 of 8 scales compared with osteoarthritis patients. CONCLUSIONS: Comparison of the SF-36 scores of patients with RLS and the normative general population suggests that the disorder has a significant impact on patient QOL.

The Johns Hopkins telephone diagnostic interview for the restless legs syndrome: preliminary investigation for validation in a multi-center patient and control population.

STUDY OBJECTIVES: To develop and validate a telephone diagnostic interview (the Johns Hopkins telephone diagnostic interview for restless legs, abbreviated TDI) for diagnosis of the restless legs syndrome (RLS). DESIGN AND METHODS: Using the International RLS Study Group diagnostic criteria, specific questions were developed reflecting the diagnostic features of RLS. Seventy-five subjects (37 previously diagnosed RLS patients and 38 controls self-reported to be free of RLS) were interviewed by three expert interviewers blinded to each others' interviews and the patient's clinical status. The interviewers diagnosed each subject based on responses to the TDI. RESULTS: The interviewers overall correctly diagnosed 72 of 75 individuals. Minimum interviewer sensitivity and specificity were 97 and 92%, respectively. The intraclass correlation coefficient (ICC) was used to quantify inter-rater reliability for the three interviewers. The ICC for diagnosis was 0.95. The ICC calculated on other key items in the interview exceeded 0.80 in all cases. The patients were predominantly older individuals with long-standing RLS; 19 of them scored at the highest level of severity on the Johns Hopkins Restless Legs Severity Scale (JHRLSS). The interviewers had more difficulty with assessing the controls accurately, some of whom were probably incorrectly self-categorized as not having RLS. CONCLUSIONS: The TDI is a sensitive, specific, and reliable instrument for diagnosing RLS by experienced interviewers in a brief, anonymous telephone encounter.

Validation of the Restless Legs Syndrome Quality of Life questionnaire.

OBJECTIVES: The Restless Legs Syndrome Quality of Life questionnaire (RLSQoL) assesses the impact of RLS on daily life, emotional well-being, social life, and work life. This study investigates its validity and reliability. METHODS: The RLSQoL was tested in 85 American adults with primary RLS. Patients were also asked to rate symptom severity with the International Restless Legs Scale (patient-reported version) and report on changes in symptoms over the 2-week period. RESULTS: The RLSQoL summary scale score (range: 0-100) demonstrated acceptable internal consistency reliability (Cronbach's alpha = 0.92) and test-retest reliability (intraclass correlation coefficient = 0.84). All items indicated acceptable item-convergent validity. The RLSQoL distinguished between groups with mild, moderate, and severe symptoms (F = 52.22, P < 0.0001). It demonstrated preliminary responsiveness to changes in RLS status over 2 weeks (effect size: improvement, 0.25; deterioration, -0.32), indicating moderate scale changes consistent with the small clinical change over this time. CONCLUSIONS: These findings support the conceptual framework of the RLSQoL. It is a valid and reliable measure of the impact of RLS on QoL and is responsive to short-term changes in symptom severity. The RLSQoL appears to be an appropriate tool for trial-based assessments of treatments for RLS.