title: Limited correlations between clinician-based and patient-based measures of essential tremor severity.
abstract: BACKGROUND
  We investigated the relation between changes in clinician-based and patient-based measures of tremor severity, within the Fahn-Tolosa-Marin Tremor Rating Scale (TRS) and Visual Analogue Scale (VAS) in essential tremor patients.
  
  
  METHODS
  Thirty-seven patients were assessed twice: on- and off-medication. Clinician-based, objective TRS assessments, consisting of part A (postures/movements) and part B (tremor-inducing tasks) were conducted by a blinded assessor using video-tapes. Patients completed TRS part C (limitations in activities of daily life) and indicated subjective tremor severity using VAS.
  
  
  RESULTS
  Patients' total TRS and VAS scores improved on-medication (both p < 0.001). Mean improvement was 6.3 (sd 5.4) points on the total TRS and 2.3 (sd 2.3) points on the VAS score. Within the TRS, we found moderate correlations between changes in clinician-based TRS-B and patient-based TRS-C scores (ρ = 0.387, p = 0.011), but not between changes in clinician-based TRS-A and TRS-C scores (ρ = 0.128, p = 0.232). Moreover, changes in subjective VAS scores correlated with changes in total TRS (ρ = 0.422, p = 0.007), changes in TRS-C scores (ρ = 0.367, p = 0.015) and, more weakly, with changes in TRS-B scores (ρ = 0.281, p = 0.049), but again: not with changes in TRS-A scores (ρ = -0.008, p = 0.482).
  
  
  CONCLUSIONS
  We found no correlation between changes in clinician-based TRS-A, and patient-based measures TRS-C or VAS scores, and a weak correlation between clinician-based TRS-B and VAS scores. The limited correlations between changes in clinician-based and patient-based measures of tremor severity suggest that the different scales measure different aspects of tremor severity and support the additional use of subjective patient-based assessments in clinical practice and clinical trials.
authors.affiliation: Department of Neurology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands. Electronic address: a.m.m.van.der.stouwe@isala.nl.
authors.forename: A M M
authors.initials: AM
authors.lastname: van der Stouwe
authors.affiliation: Department of Neurology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Broersma
authors.affiliation: Department of Neurology & Clinical Neurophysiology, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: A W G
authors.initials: AW
authors.lastname: Buijink
authors.affiliation: Department of Neurology & Clinical Neurophysiology, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: A F
authors.initials: AF
authors.lastname: van Rootselaar
authors.affiliation: Department of Neurology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: N M
authors.initials: NM
authors.lastname: Maurits
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D020329:Essential Tremor / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006282:Health Personnel; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D010361:Patients; D011187:Posture; D012720:Severity of Illness Index
keywords: Essential tremor; Tremor rating scale; Tremor severity