title: Characteristics of Task-specific Tremor in String Instrument Players.
abstract: BACKGROUND
  In recent studies primary bowing tremor has been described; however, tremor frequency has never been quantitatively assessed. In addition to describing phenomenological aspects of tremor we thus aimed at assessing tremor frequency. Our hypothesis was that primary bowing tremor is similar to the phenomenological aspects and frequency of primary writing tremor.
  
  
  METHODS
  WE QUANTIFIED PRIMARY BOWING TREMOR IN FOUR VIOLINISTS UNDER TWO CONDITIONS: open strings and a G major scale. Data were analyzed using empirical mode decomposition because it takes into account non-stationarity and non-linearity of signals. For each patient we further described tremor phenomenology and assessed symptom onset, risk factors, medication, and family history with a structured anamnesis. We compare the findings to previous findings for primary bowing tremor and primary writing tremor.
  
  
  RESULTS
  We mainly found a flexion-extension tremor of the wrist with a frequency range of 4.7-6.7 Hz. There was no significant difference between the conditions. Mean onset age was 43±2.4 years. Medication included trihexyphenidyl, propranolol, primidone, and botulinum toxin. We found a positive family history in two patients and an injury prior to symptom onset in another two patients. Comparison of onset age, frequency range, family history, and injuries prior to onset revealed that our findings are very similar to previous findings on primary bowing tremor and primary writing tremor.
  
  
  CONCLUSIONS
  Our findings confirmed our hypothesis that primary bowing tremor is similar to primary writing tremor, with regard to phenomenology and epidemiology as well as tremor frequency. There was no difference in tremor frequency between conditions, suggesting that tremor is not influenced by bimanual coordination or bowing speed. Our findings thus provide new phenomenological aspects and may contribute to a better understanding of primary bowing tremor.
authors.affiliation: University of Music, Drama and Media Hannover, Emmichplatz 1, 30175 Hannover, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Lee
authors.affiliation: University of Music, Drama and Media Hannover, Emmichplatz 1, 30175 Hannover, Germany ; Hannover Medical University, Carl-Neuberg-Str.1, 30625 Hannover, Germany.
authors.forename: Mareike
authors.initials: M
authors.lastname: Chadde
authors.affiliation: University of Music, Drama and Media Hannover, Emmichplatz 1, 30175 Hannover, Germany.
authors.forename: Eckart
authors.initials: E
authors.lastname: Altenmüller
authors.affiliation: University of Music, Drama and Media Hannover, Emmichplatz 1, 30175 Hannover, Germany.
authors.forename: Erwin
authors.initials: E
authors.lastname: Schoonderwaldt
keywords: Essential tremor; Hilbert spectrum; dystonia; dystonic tremor; empirical mode decomposition; musician