title: Validation of a portable instrument for assessing tremor severity in epidemiologic field studies.
abstract: BACKGROUND
  An important part of epidemiologic and genetic studies of essential tremor (ET) is an assessment of tremor severity. Clinical rating scales are semiquantitative and computerized tremor analysis, available at tertiary medical centers, is not transportable into the field. As part of an epidemiologic study, we modified the Klove-Matthews Motor Steadiness Battery, collecting objective quantitative data on tremor severity in patients with ET and control subjects.
  
  
  OBJECTIVE
  To describe the modified Klove-Matthews Motor Steadiness Battery, validate this test battery against several other measures of tremor severity, demonstrate test-retest reliability, and provide standard reference values for normal control subjects and patients with ET who undergo this test battery.
  
  
  METHODS
  Patients with ET and control subjects, ascertained from both a clinic and a community, underwent a standardized evaluation including a demographic and medical questionnaire, tremor disability questionnaire, videotaped tremor examination, performance-based test, modified Klove-Matthews Motor Steadiness Battery (Groove-Type Steadiness Tester [GTST] and Nine-Hole Steadiness Tester [NHST]), and quantitative computerized tremor analysis.
  
  
  RESULTS
  There were 19 patients with ET and 28 control subjects. NHST and GTST total scores were correlated significantly with the tremor disability questionnaire score (r = 0.63, p = 0.001 and r = 0.49, p = 0.016), total tremor score (tremor examination, r = 0.68, p<0.001 and r = 0.41, p = 0.005), performance-based test score (r = 0.81, p<0.001 and r = 0.65, p = 0.001), and quantitative computerized tremor analysis results (for example, spiral drawing, r = 0.62, p = 0.01 and r = 0.58, p = 0.019). Test-retest reliability was generally high (r = 0.79-0.94, p<0.001).
  
  
  CONCLUSIONS
  The modified Klove-Matthews Motor Steadiness Battery provides a reliable and valid means to collect objective quantitative data on tremor severity. Rapidity of administration and ease of transport make it a potentially useful tool in epidemiologic and genetic field studies.
authors.affiliation: Department of Neurology and the Gertrude H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
authors.forename: E D
authors.initials: ED
authors.lastname: Louis
authors.forename: E
authors.initials: E
authors.lastname: Yousefzadeh
authors.forename: L F
authors.initials: LF
authors.lastname: Barnes
authors.forename: Q
authors.initials: Q
authors.lastname: Yu
authors.forename: S L
authors.initials: SL
authors.lastname: Pullman
authors.forename: K J
authors.initials: KJ
authors.lastname: Wendt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation; D004576:Electromyography / Q000295:instrumentation*; D016021:Epidemiologic Studies; D004867:Equipment Design; D020329:Essential Tremor / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D009460:Neurologic Examination / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*