Leg movement activity during sleep in multiple sclerosis with and without restless legs syndrome.

STUDY OBJECTIVES: To carry out an analysis of leg movement activity during sleep in a polysomnography dataset of patients with multiple sclerosis (MS) in comparison to idiopathic restless legs syndrome (iRLS) and healthy controls. METHODS: In this cross-sectional, observational, instrumental study, 57 patients (males/females: 11/46; mean age 46.2 ± 10.2 years) with a diagnosis of MS underwent a telephone interview assessing the 5 standard diagnostic criteria for RLS and polysomnography. Sleep architecture and leg movement activity during sleep were subsequently compared: 1) 40 patients with MS without RLS (MS-RLS) vs 28 healthy controls; 2) 17 patients with MS with RLS (MS+RLS) vs 35 patients with iRLS; 3) MS+RLS vs MS-RLS. RESULTS: MS-RLS and MS+RLS presented increased sleep latency, percentage of sleep stage N1, and reduced total sleep time compared to healthy controls and iRLS, respectively. The periodic limb movements during sleep (PLMS) index was higher in MS-RLS than in healthy controls (P = .035) and lower in MS+RLS compared to iRLS (P = .024). PLMS in MS+RLS were less periodic, less often bilateral, and with shorter single movements compared to the typical PLMS in iRLS. CONCLUSIONS: MS is a risk factor for RLS, PLMS, and for a lower sleep quality in comparison to healthy patients. PLMS in MS+RLS are fewer and shorter if compared to iRLS. Our results suggest a dissociation between motor (PLMS) and sensory symptoms (RLS sensory component) in RLS secondary to MS, with possible treatment implications. CITATION: Ferri R, Sparasci D, Castelnovo A, et al. Leg movement activity during sleep in multiple sclerosis with and without restless legs syndrome. J Clin Sleep Med. 2022;18(1):11-20.

Restless legs syndrome and periodic limb movements in 86 patients with multiple sclerosis.

STUDY OBJECTIVES: To assess the frequency of restless legs syndrome (RLS), periodic limb movements during sleep (PLMS), and their overlap in a large sample of patients with multiple sclerosis (MS). To compare clinical and paraclinical findings among four subgroups of patients: RLS-/PLMS- (patients without RLS and PLMS), RLS+/PLMS- (patients with RLS and without PLMS), RLS-/PLMS (patients without RLS and with PLMS), and RLS+/PLMS+ (patients with both RLS and PLMS). METHODS: In this cross-sectional, observational, instrumental study, 86 patients (M/F: 27/59; mean age 48.0 ± 10.8 years) with a diagnosis of MS underwent a telephone interview assessing the five standard diagnostic criteria for RLS. Seventy-six participants underwent polysomnography (PSG) and maintenance of wakefulness test (MWT). Instrumental and clinical findings were subsequently statistically compared to investigate their association with RLS and PLMS index (PLMSI). RESULTS: RLS and PLMS (PLMSI ≥15/h) frequency in patients with MS were of 31.4% and 31.6%, respectively. Among patients with RLS, 37.5% had a PLMSI of at least 15/h. RLS-/PLMS+ group showed higher wake after sleep onset (p = 0.01), stage shifts per hour (p = 0.03), increased stage N1 (p = 0.03), and reduction in stage N3 (p = 0.01) compared to RLS-/PLMS-. RLS had no influence on clinical and PSG parameters (p = 0.45). CONCLUSIONS: RLS is highly frequent in patients with MS. The frequency of PLMS is comparable to the general population. The low percentage of patients with RLS having a high PLMSI, together with the absence of correlation between RLS and female gender and older age, supports the existence of a distinct symptomatic form of RLS in MS.