title: The high frequency of periodic limb movements in patients with Lewy body dementia.
abstract: BACKGROUND
  Although dementia with Lewy bodies (DLB) is the second most common form of neurodegenerative dementia after Alzheimer's disease (AD), the clinical diagnosis is frequently difficult. Because both REM sleep behavior disorders and Parkinson's disease also have alpha-synucleinopathy similar to DLB, and show an increase in periodic limb movements (PLM), we evaluated the association between DLB and PLM, which may serve as an additional information to differentiate AD and DLB.
  
  
  METHODS
  Overnight polysomnographic recordings were performed for the inpatients in our hospital who were suspected to have dementia. The quality of sleep, oxygen-desaturation index and periodic limb movements were compared among the patients clinically diagnosed with DLB, AD or as having no dementia.
  
  
  RESULTS
  Nine DLB patients, twelve AD patients and ten non-demented patients were enrolled in the study. The number of PLM during sleep per hour of total sleep time (PLMS index) was significantly higher in the DLB patients than the AD patients or the non-demented patients. No significant differences were found between the AD patients and the non-demented patients. To differentiate DLB from AD, a PLMS index of more than 15.0 had a sensitivity of 88.9% and a specificity of 83.3%.
  
  
  CONCLUSIONS
  The DLB patients exhibited a higher PLMS index than the AD patients, and this index could be clinically useful for the diagnostic differentiation of DLB from AD.
authors: Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors: Shinichiro
authors: S
authors: Hibi
authors: Yasuhiro
authors: Y
authors: Yamaguchi
authors: Yumi
authors: Y
authors: Umeda-Kameyama
authors: Hiroshi
authors: H
authors: Yamamoto
authors: Katsuya
authors: K
authors: Iijima
authors: Toshimitsu
authors: T
authors: Momose
authors: Masahiro
authors: M
authors: Akishita
authors: Yasuyoshi
authors: Y
authors: Ouchi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000544:Alzheimer Disease / Q000175:diagnosis / Q000503:physiopathology*; D005121:Extremities / Q000294:innervation / Q000503:physiopathology*; D005260:Female; D006801:Humans; D020961:Lewy Body Disease / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D009483:Neuropsychological Tests; D017286:Polysomnography; D011569:Psychiatric Status Rating Scales; D020187:REM Sleep Behavior Disorder / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D013997:Time Factors