Essential tremor-Parkinson's disease: A double whammy

Elan D. Louis, Adina Wise, Roy N. Alcalay, Ashwini K. Rao, Pam Factor-Litvak

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Background Surprisingly little has been written about the combined clinical entity, essential tremor-Parkinson's disease (ET-PD), which is the result of a double disease hit. We carefully quantified tremor burden using a wide range of measures (tremor severity, tremor-related disability, tremor-related quality of life) and furthermore, studied additional motor and non-motor features in ET-PD. Methods In this prospective, clinical-epidemiological study, we performed a standardized, structured clinical evaluation of 27 ET-PD patients, comparing them to age-matched samples of 35 PD and 109 ET patients. Results The number of hours/day shaking was lowest in PD (median = 3.0), intermediate in ET (median = 10.0) and highest in ET-PD (median = 14.0) (p < 0.001). All measures of mobility and balance (Berg Balance test, Activities-specific Balance Confidence Scale, Timed Up and Go test) worsened across groups in a stepwise manner from ET to PD to ET-PD (p < 0.05). Mini-mental state test scores worsened (p = 0.002) and daytime sleepiness increased (p = 0.002) across groups from ET to PD to ET-PD. Conclusions The ET-PD patient seems to be more than just a PD patient with a little more kinetic tremor. Aside from a significantly greater tremor burden, ET-PD patients exhibited more cognitive and sleep problems and more mobility and balance problems than patients with isolated PD.

Original languageEnglish (US)
Pages (from-to)47-51
Number of pages5
JournalJournal of the Neurological Sciences
StatePublished - Jul 15 2016
Externally publishedYes


  • Clinical
  • Essential tremor
  • Parkinson's disease

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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