title: Triggering essential head tremor with sustained phonation: a clinical phenomenon with potential diagnostic value.
abstract: Here we report a clinical phenomenon that we have observed repeatedly in clinical research settings; namely, a triggering and/or exacerbation of head tremor during or immediately following sustained phonation. To our knowledge, it has not been reported previously nor has it been the subject of study. Here we: 1) report the phenomenon, 2) provide several visual illustrations, 3) estimate its prevalence, and 4) analyze its clinical correlates. Head tremor was assessed qualitatively, and scores were assigned pre-, during, and post-sustained phonation using the Tremor Research Group Essential Tremor Rating Assessment Scale. Seventy (68.6%) of 102 essential tremor (ET) patients exhibited a qualitative increase in head tremor amplitude during and/or immediately after sustained phonation; in 5 (4.9%), head tremor would not have been detected without the voice activation maneuver (i.e., it was not visible at any other point in the videotape aside from the period during/immediately following sustained phonation). Women were more likely than men to exhibit this phenomenon (p = 0.05), whereas age, age at onset, duration of tremor, and total tremor score did not predict responsiveness of head tremor to sustained phonation. Sustained voice activation is a useful examination maneuver that may elicit or amplify head tremor in ET. Head tremor is not reported to occur in patients with enhanced physiological tremor. Thus, this maneuver, by triggering head tremor, may be a useful diagnostic supplement, particularly in research/clinical settings where arm tremor is mild and the diagnosis (mild ET vs. enhanced physiological tremor) would otherwise be ambiguous.
authors.affiliation: Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
authors.forename: Brenton A
authors.initials: BA
authors.lastname: Wright
authors.affiliation: GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
authors.forename: Monika
authors.initials: M
authors.lastname: Michalec
authors.affiliation: Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA; GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA. Electronic address: EDL2@columbia.edu.
authors.forename: Elan D
authors.initials: ED
authors.lastname: Louis
mesh_terms: D000368:Aged; D020329:Essential Tremor / Q000175:diagnosis*; D005260:Female; D006257:Head; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination / Q000379:methods*; D010699:Phonation
keywords: Clinical; Essential tremor; Examination; Head tremor