title: The validity of the PAM-RL device for evaluating periodic limb movements in sleep and an investigation on night-to-night variability of periodic limb movements during sleep in patients with restless legs syndrome or periodic limb movement disorder using this system.
abstract: BACKGROUND
  The status of night-to-night variability for periodic limb movements in sleep (PLMS) has not been clarified. With this in mind, we investigated the validity of PLMS measurement by actigraphy with the PAM-RL device in Japanese patients with suspected restless legs syndrome (RLS) or periodic limb movement disorder (PLMD) and the night-to-night variability of PLMS among the subjects.
  
  
  METHODS
  Forty-one subjects (mean age, 52.1±16.1 years) underwent polysomnography (PSG) and PAM-RL measurement simultaneously. Thereafter, subjects used the PAM-RL at home on four more consecutive nights.
  
  
  RESULTS
  The correlation between PLMS index on PSG (PLMSI-PSG) and PLM index on PAM-RL (PLMI-PAM) was 0.781 (P<.001). When the PLMSI cutoff value on PSG was set at 15 episodes per hour, the cutoff value for predicting this PLMSI level was 16.0 episodes per hour. When the condition was set to the level in which the mean interclass correlation coefficient reached ≥0.9, the number of required nights for repeated measurements was 26 nights for subjects with PLMI of <15 episodes per hour and three nights for those with PLMI ≥15 episodes per hour on PAM-RL.
  
  
  CONCLUSIONS
  PAM-RL is thought to be valuable for assessing PLMS even in Japanese subjects. Recording of PAM-RL for three or more consecutive nights may be required to ensure the screening reliability of a patient with suspected pathologically frequent PLMS.
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan; Yoyogi Sleep Disorder Center, Tokyo, Japan.
authors.forename: Mina
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan; Yoyogi Sleep Disorder Center, Tokyo, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Namba
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan; Yoyogi Sleep Disorder Center, Tokyo, Japan.
authors.forename: Eiki
authors.initials: E
authors.lastname: Ito
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan; Yoyogi Sleep Disorder Center, Tokyo, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Nishida
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan; Yoyogi Sleep Disorder Center, Tokyo, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Ueki
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Naomichi
authors.initials: N
authors.lastname: Furudate
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kagimura
authors.affiliation: Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan; Yoyogi Sleep Disorder Center, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Usui
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan; Yoyogi Sleep Disorder Center, Tokyo, Japan. Electronic address: inoue@somnology.com.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D020189:Nocturnal Myoclonus Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D017286:Polysomnography / Q000379:methods / Q000592:standards*; D012372:ROC Curve; D015203:Reproducibility of Results; D012148:Restless Legs Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D012680:Sensitivity and Specificity; D012894:Sleep Stages / Q000502:physiology*
keywords: Night-to-night variability; PAM-RL; Periodic limb movement; Polysomnography; Restless legs syndrome; Validation