Comparison of motor and non-motor features between essential tremor and tremor dominant Parkinson's disease

Kyum Yil Kwon, Hye Mi Lee, Seon Min Lee, Sung Hoon Kang, Seong Beom Koh

Research output: Contribution to journalArticle

11 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)34-38
Number of pages5
JournalJournal of the Neurological Sciences
Publication statusPublished - 2016 Feb 15


  • Essential tremor
  • non-motor symptom
  • Parkinson's disease
  • Surface electromyogram
  • Tremor dominant

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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