title: Case-control study of risk factors for spasmodic dysphonia: A comparison with other voice disorders.
abstract: OBJECTIVE
  This epidemiology study examined risk factors uniquely associated with spasmodic dysphonia (SD).
  
  
  METHODS
  Case-control.
  
  
  METHODS
  A questionnaire was administered to 150 patients with SD (with and without coexisting vocal tremor) and 136 patients with other structural, neurological, and functional voice disorders (excluding SD and vocal tremor). Questions included personal and family medical histories, environmental exposures, trauma, illnesses, voice use habits, and the Short Form 36.
  
  
  RESULTS
  Several factors were uniquely associated with SD (α = .05), including: 1) a personal history of cervical dystonia, sinus and throat illnesses, mumps, rubella, dust exposure, and frequent volunteer voice use, 2) a family history of voice disorders, 3) an immediate family history of vocal tremor and meningitis, and 4) an extended family history of head and neck tremor, ocular disease, and meningitis. Vocal tremor coexisted with SD in 29% of cases. Measles and mumps vaccines were protective for SD.
  
  
  CONCLUSIONS
  SD is likely multifactorial and associated with several endogenous and exogenous factors. Certain viral exposures, voice use patterns, and familial neurological conditions may contribute to the onset of SD later in life.
authors.affiliation: Department of Communication Sciences and Disorders, The University of Utah, Salt Lake City, Utah, USA. kristine.tanner@hsc.utah.edu
authors.forename: Kristine
authors.initials: K
authors.lastname: Tanner
authors.forename: Nelson
authors.initials: N
authors.lastname: Roy
authors.forename: Ray M
authors.initials: RM
authors.lastname: Merrill
authors.forename: Cara
authors.initials: C
authors.lastname: Sauder
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Houtz
authors.forename: Marshall E
authors.initials: ME
authors.lastname: Smith
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055154:Dysphonia / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013035:Spasm / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D011795:Surveys and Questionnaires; D014589:Utah / Q000453:epidemiology; D014832:Voice Disorders / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D014833:Voice Quality; D055815:Young Adult