title: Comparison of motor and non-motor features between essential tremor and tremor dominant Parkinson's disease.
abstract: BACKGROUND
  Differential diagnosis of tremor disorders, including essential tremor (ET) and Parkinson's disease-tremor dominant type (PD-TDT), requires further investigation. Therefore, the current study aimed to compare non-motor and tremor features in order to differentiate between ET and PD-TDT.
  
  
  METHODS
  Twenty-eight patients with classic ET and 24 patients with typical PD-TDT were retrospectively enrolled in a multi-stage investigation process. Tremor features including surface electromyogram (EMG) were analyzed in detail. For non-motor symptom analyses, the global cognition test, frontal function test, and non-motor symptoms scale (NMSS) were administered, in addition to collecting patient history data.
  
  
  RESULTS
  Patients with PD-TDT presented with more asymmetric tremor, whereas patients with ET presented with more symmetric tremor. Leg tremor was observed only in patients with PD-TDT. Surface EMG analyses of arm tremor demonstrated considerable overlaps in tremor type, tremor frequency, and contractive patterns. However, patients with PD-TDT were significantly more likely to exhibit resting tremor, and experienced alternative contraction patterns only for kinetic tremor, which was in contrast to patients with ET. For non-motor symptom analyses, patients with PD-TDT had more non-motor symptoms compared to patients with ET (mean=5.0 vs. 2.6; P=0.002). Specifically, patients with PD-TDT exhibited higher frequencies of hyposmia, REM sleep behavior disorder (RBD)-like symptom, urinary frequency, and memory disturbance. Age- and gender- matched analyses for the severity of NMSS scores did not indicate significant differences. However, patients with PD-TDT displayed slightly lower scores of frontal function test compared to patients with ET.
  
  
  CONCLUSIONS
  Careful and detailed evaluations of both tremor features and non-motor symptoms are required in order to distinguish between ET and PD-TDT.
authors.affiliation: Department of Neurology and Parkinson's Disease Centre, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea; Department of Neurology, Soonchunhyang University Gumi Hospital, Soonchunhyang University School of Medicine, Gumi, Republic of Korea.
authors.forename: Kyum-Yil
authors.initials: KY
authors.lastname: Kwon
authors.affiliation: Department of Neurology and Parkinson's Disease Centre, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hye Mi
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Department of Neurology and Parkinson's Disease Centre, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Seon-Min
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Department of Neurology and Parkinson's Disease Centre, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Kang
authors.affiliation: Department of Neurology and Parkinson's Disease Centre, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea. Electronic address: parkinson@korea.ac.kr.
authors.forename: Seong-Beom
authors.initials: SB
authors.lastname: Koh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003072:Cognition Disorders / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D003937:Diagnosis, Differential; D004576:Electromyography; D020329:Essential Tremor / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology; D010300:Parkinson Disease / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D020187:REM Sleep Behavior Disorder / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D012720:Severity of Illness Index; D055815:Young Adult
keywords: Essential tremor; Parkinson's disease; Surface electromyogram; Tremor dominant; non-motor symptom