title: Bilateral leg movements during sleep: detailing their structure and features in normal controls and in patients with restless legs syndrome.
abstract: OBJECTIVE
  The aim of this study was to analyze statistically the number of single leg movements (LMs) forming bilateral LMs during sleep, along with their combined duration, to eventually provide evidence-based data for the adjustment of the current scoring rules defining bilateral LMs.
  
  
  METHODS
  Polysomnographic recordings of 111 untreated patients with RLS with a median age of 56.0 years, along with 42 normal controls with a mean age of 60.0 years, were included. In each recording, we identified all LMs that were considered as bilateral when two or more LMs were overlapping or the onset of the following movement was <0.5 second after the offset of the preceding LM. The remaining LMs were classified as monolateral. A series of parameters were computed for both bilateral and monolateral LMs.
  
  
  RESULTS
  The duration of monolateral LMs in RLS patients was significantly longer than that of normal controls. For bilateral LMs, the maximum number of single LMs forming a bilateral movement and the maximum duration were slightly higher in RLS patients; however, the distribution of the number of individual LMs forming a single bilateral LM was similar. Only 0.12% and 0.27% of bilateral LMs consisted of >4 individual movements, and only 0.16% and 1.90% of bilateral LMs were >15 seconds in RLS patients and healthy controls, respectively.
  
  
  CONCLUSIONS
  Our results strongly suggest that bilateral LMs during sleep should be constituted by no more than four individual LMs and should have a maximum duration of 15 seconds.
authors.affiliation: Department of Neurology I.C., Sleep Research Centre, Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy. Electronic address: rferri@oasi.en.it.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Ferri
authors.affiliation: Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital (EOC) of Lugano, Lugano, Switzerland.
authors.forename: Mauro
authors.initials: M
authors.lastname: Manconi
authors.affiliation: Department of Neurology I.C., Sleep Research Centre, Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Rundo
authors.affiliation: Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital (EOC) of Lugano, Lugano, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Zucconi
authors.affiliation: Department of Neurology I.C., Sleep Research Centre, Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy.
authors.forename: Debora
authors.initials: D
authors.lastname: Aricò
authors.affiliation: Department of Social and Developmental Psychology, Sapienza University, Rome, Italy.
authors.forename: Oliviero
authors.initials: O
authors.lastname: Bruni
authors.affiliation: Department of Neurology I.C., Sleep Research Centre, Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy.
authors.forename: Filomena I I
authors.initials: FII
authors.lastname: Cosentino
authors.affiliation: Department of Neurology, Sleep Disorders Center, Scientific Institute and University Ospedale San Raffaele, Vita-Salute University, Milan, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferini-Strambi
authors.affiliation: Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital (EOC) of Lugano, Lugano, Switzerland.
authors.forename: Stephany
authors.initials: S
authors.lastname: Fulda
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D009068:Movement; D020189:Nocturnal Myoclonus Syndrome / Q000145:classification; D012148:Restless Legs Syndrome / Q000145:classification
keywords: Bilateral leg movements; PLMS; Periodic leg movements during sleep; Restless legs syndrome; Sleep scoring