title: Comparison of severity of obstructive sleep apnea and degree of accumulation of cardiac 123I-MIBG radioactivity as a diagnostic marker for idiopathic REM sleep behavior disorder.
abstract: OBJECTIVE
  We investigated cardiac (123)I-metaiodobenzylguanidine (MIBG) scintigraphic assessment as a supportive diagnostic indicator for idiopathic REM sleep behavior disorder (RBD) complicated by moderate to severe obstructive sleep apnea (OSA).
  
  
  METHODS
  (123)I-MIBG was intravenously injected in 23 idiopathic RBD patients with AHI < 5/h, 9 idiopathic RBD patients with 5 <or= AHI < 15/h, 15 idiopathic RBD patients complicated with moderate to severe OSA with AHI >or= 15/h, and 16 moderate to severe obstructive sleep apnea syndrome (OSAS) patients without RBD by polysomnography.
  
  
  RESULTS
  Cardiac MIBG uptake based on H/M was significantly decreased in RBD patients with or without OSA compared with patients with moderate to severe OSAS without RBD. ROC analysis revealed that a delayed H/M cut-off value of 1.97 was useful for differentiating idiopathic RBD complicated by moderate to severe OSA from moderate to severe OSAS without RBD.
  
  
  CONCLUSIONS
  (123)I-MIBG cardiac scintigraphy has the potential to distinguish true RBD from pseudo-RBD associated with OSA. These results are noteworthy because treatment options and follow-up protocols are determined based on evaluation of moderate to severe OSA complicated with RBD, such as overlapping primary sleep disorders.
authors.affiliation: Department of Neurology, Center of Sleep Medicine, Dokkyo Medical University School of Medicine, Shimotsuga, Tochigi 321-0293, Japan. miyatomo@dokkyomed.ac.jp
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Miyamoto
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyamoto
authors.forename: Keisuke
authors.initials: K
authors.lastname: Suzuki
authors.forename: Akiko
authors.initials: A
authors.lastname: Ikematsu
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Usui
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
authors.forename: Koichi
authors.initials: K
authors.lastname: Hirata