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Sleep Med. 2015 Jul;16(7):877-82. doi: 10.1016/j.sleep.2015.02.529. Epub 2015 Mar 6.

High false-positive rate of questionnaire-based restless legs syndrome diagnosis in multiple sclerosis.

Author information

1
Respiratory Division and Sleep Laboratory, McGill University Health Centre, 687 Pine Ave. West, Montreal, QC H3A 1A1, Canada.
2
Department of Medicine, McGill University Health Centre, 687 Pine Ave West, Montreal, QC H3A 1A1, Canada; Department of Epidemiology, Biostatistics & Occupational Health, McGill University, 1020 Pine Ave. West, Montreal, QC H3A 1A2, Canada; Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University, 3650 St. Urbain St, Montreal, QC H2X 2P4, Canada.
3
Respiratory Division and Sleep Laboratory, McGill University Health Centre, 687 Pine Ave. West, Montreal, QC H3A 1A1, Canada; Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University, 3650 St. Urbain St, Montreal, QC H2X 2P4, Canada.
4
Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University Health Centre, 3801 University St., Montreal, QC H3A 2B4, Canada.
5
Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University Health Centre, 3801 University St., Montreal, QC H3A 2B4, Canada. Electronic address: daria.trojan@mcgill.ca.

Abstract

BACKGROUND/OBJECTIVES:

Restless legs syndrome (RLS) is diagnosed by self-reported symptoms. Multiple sclerosis (MS) patients have disease-related symptoms which could mimic RLS. This study assessed the: (1) false-positive rate for questionnaire-based RLS diagnosis in MS patients and (2) utility of periodic leg movements during wakefulness (PLMW) on overnight polysomnography (PSG) in identifying true-positive RLS patients.

METHODS:

Ambulatory MS patients without known sleep disorders were recruited. Subjects completed the International RLS Study Group (IRLSG) diagnostic questionnaire (IRLDQ) and underwent full overnight PSG. IRLDQ-positive patients underwent clinical evaluation to confirm the diagnosis and completed the RLS severity scale (IRLS).

RESULTS:

Seventy-one MS patients (mean age 46.8 ± 10.4 years) were evaluated. Thirty-eight had a positive IRLDQ. RLS diagnosis was confirmed in 22, yielding a false-positive rate of 42% [95% confidence interval (CI) 26-59%], predominantly attributable to paresthesiae (n = 7), and cramps and/or muscle spasms (n = 4). IRLS scores were not significantly different between subjects with confirmed and nonconfirmed RLS. The PLMW index was significantly higher in patients with confirmed RLS (55.4 ± 41.9 vs. 29.7 ± 18.8, p = 0.03). The sensitivity of a PLMW index >70/h for true-positive IRLDQ was 8/22 = 36%, 95% CI: 17.2-59.3, and the specificity was 16/16 = 100%, 95% CI: 79.4-100.

CONCLUSIONS:

MS patients have a high false-positive rate of RLS diagnosis using a standardized questionnaire largely attributable to MS-related sensorimotor symptoms. While detailed clinical evaluation is essential for confirming RLS diagnosis, the PLMW index may provide useful adjunctive information.

KEYWORDS:

International Restless Legs Syndrome Study Group questionnaire; Multiple sclerosis; Periodic leg movements; Polysomnography; Restless legs syndrome

PMID:
25912601
DOI:
10.1016/j.sleep.2015.02.529
[Indexed for MEDLINE]

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