• Elan D Louis, Monica Michalec, and Art Gillman.
• GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, USA.
• BMJ Open. 2014 Jan 1; 4 (4): e004626.

ObjectiveFew studies have attempted to estimate the rate of decline over time in essential tremor (ET). The study objectives were to: (1) measure change, deriving a single summary measure for the entire group, and relate it to a commonly used clinical rating scale (ie, yearly change in points on that scale); (2) to assess change as a function of baseline clinical characteristics and (3) to answer the basic clinical question-is change perceptible/obvious during the follow-up of ET cases?SettingProspective collection of longitudinal data on ET cases enrolled in a study of the environmental epidemiology of ET at Columbia University Medical Center (2000-2008).Participants116 unselected ET cases.InterventionsEach case underwent the same evaluation at baseline and during one follow-up visit (mean follow-up interval (range)=5.8 (1.4-12.4) years).Primary And Secondary Outcome MeasuresWe assessed tremor during a commonly affected daily activity-drawing (ie, spirography), quantifying tremor using a simple, standardised 10-point rating scale developed by Bain and Findley.ResultsThe Bain and Findley spiral score increased at an average rate of 0.12±0.23 points per year (maximum=1 point/year). In cases who had been followed for ≥5 years, the change was obvious-a blinded neurologist was able to correctly order their spirals (baseline vs follow-up) in three-fourth of cases. The rate of change was higher in cases with versus without familial ET (p=0.01).ConclusionsTremor in ET is slowly progressive; yet in the majority of cases, a clear difference in handwritten spirals was visible with a follow-up interval of five or more years. There may be differences between familial and non-familial ET in the rate of progression. These clinical data are intended to aid in the prognostic discussions that treating physicians have with their patients with ET.

15 keywords...

hide…