title: Essential tremor 10, 20, 30, 40: clinical snapshots of the disease by decade of duration.
abstract: OBJECTIVE
  Essential tremor (ET) is a chronic, progressive neurological disorder in which disease burden may slowly accrue. There are few long-term studies, and the clinical and functional status of patients, with each decade of disease duration, has not been documented in detail. We used cross-sectional data on 335 patients with ET (disease duration 1-81 years) to produce clinical snapshots of the disease at each 10-year milestone (i.e. < 10, 10-19, 20-29, 30-39, ≥ 40 years). We hope these data will be of value in clinical-prognostic settings both to patients and their treating physicians.
  
  
  METHODS
  In this cross-sectional, clinical-epidemiological study at Columbia-University Medical Center, each patient underwent a single evaluation, including self-reported measures of tremor-related disability, performance-based measures of function, and neurologist-assessments of tremor type, location and severity.
  
  
  RESULTS
  A variety of metrics of tremor severity increased across the 10-year time intervals. By ≥ 40 years duration, one-third of patients had tremor in at least two cranial locations (neck, voice, jaw), and the proportion with high-amplitude tremor reached 20.3% (while drawing spirals), 33.8% (spilling while drinking) and 60.8% (spilling while using a spoon). Yet even in the longest tremor duration group, very few (< 10%) were incapacitated (i.e. completely unable to perform the above-mentioned tasks), and one-third continued to exhibit no cranial tremor.
  
  
  CONCLUSIONS
  These data paint a picture of progressive decade-by-decade decline in ET. Yet patients with long disease duration did not relentlessly converge at the same end-stage of severe, functionally incapacitating, diffuse tremor. In this respect, long-duration ET patients presented a heterogeneous picture.
authors.affiliation: G.H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA. EDL2@columbia.edu
authors.forename: E D
authors.initials: ED
authors.lastname: Louis
authors.forename: M
authors.initials: M
authors.lastname: Gerbin
authors.forename: M
authors.initials: M
authors.lastname: Galecki
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D018450:Disease Progression; D020329:Essential Tremor / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult