title: Heart rate variability to differentiate essential tremor from early-stage tremor-dominant Parkinson's disease.
abstract: BACKGROUND
  Essential tremor (ET) and Parkinson's disease (PD) are the most common movement disorders in the elderly, but it is difficult to differentiate ET from early-stage tremor-dominant Parkinson's disease (TDPD).
  
  
  METHODS
  We investigated heart rate variability (HRV) in 23 patients with ET, 27 patients with TDPD, and 23 healthy controls. HRV was determined using the RR intervals of a 5-min electrocardiogram recording. Measurements of beat-to-beat RR variability, including time domains [(standard deviation of the normal-to-normal RR interval (SDNN), and the root mean square difference of successive RR intervals (RMSSD)] and frequency domains [low-frequency (LF) and high-frequency (HF) components and total spectral power (TP)], were assessed retrospectively.x
  
  
  RESULTS
  In the TDPD group, SDNN, LF, HF, and TP were significantly lower than those in the ET group. In a receiver operating characteristic area under the curve (AUC) analysis, LF was the best potential diagnostic marker (AUC=0.87).
  
  
  CONCLUSIONS
  Non-invasive and routine electrocardiography may be helpful in differentiating ET from TDPD during the early disease stage.
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea. Electronic address: jhyoon@gmail.com.
authors.forename: Jung Han
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Min Seung
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Sun Min
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Hyun Jae
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Ji Man
authors.initials: JM
authors.lastname: Hong
mesh_terms: D019540:Area Under Curve; D003937:Diagnosis, Differential; D004562:Electrocardiography; D020329:Essential Tremor / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D000070276:Heart Rate Determination; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology*; D011446:Prospective Studies; D012372:ROC Curve; D012189:Retrospective Studies
keywords: Cardiac autonomic function; Essential tremor; Heart rate variability; Parkinson's disease