title: The Effect of Head Position and/or Stance on the Self-perception of Phonatory Effort.
abstract: BACKGROUND
  Vocal fatigue is a common but poorly defined complaint of patients presenting with voice disorders. Definitions of vocal fatigue generally include increased self-perceived phonatory effort resulting from references to vocal loading or prolonged voice use resulting in deterioration of function. The present study looks at the role of posture, specifically head position and stance, in self-perceived phonatory effort.
  
  
  METHODS
  Forty-six healthy adults, 13 males and 33 females (mean age was 27.5), with no history of vocal problems/disorders within the past year were recruited. Subjects were asked to sustain the vowel /a/ at a comfortable pitch and loudness for 5-10 seconds in each of six positions: sitting and standing in the manner habitual for each subject, two exaggerated positions of the head (head back and head forward), and two exaggerated positions in standing (standing with knees locked and with knees soft). Each position was repeated three times in randomized order, resulting in 18 trials for each subject. After each repetition of the sustained /a/, subjects were asked to rate their experience of vocal effort using a 100-mm visual analog scale (0-40 least effort, 40-60 habitual effort, and 60-100 increased effort).
  
  
  RESULTS
  Repeated measures analysis of variance revealed significant difference in the self-perceived phonatory effort levels across positions (P value < 0.001). The exaggerated forward and back head positions in both sitting and standing positions showed the greatest significance on the Tukey post hoc tests (P < 0.000).
  
  
  CONCLUSIONS
  Based on the findings, posture may play a more important role in vocal fatigue than previously thought.
authors.affiliation: Speech-Language Pathology, The Emory Voice Center, Department of Otolaryngology, Emory University, Atlanta, Georgia. Electronic address: marina.gilman@emoryhealthcare.org.
authors.forename: Marina
authors.initials: M
authors.lastname: Gilman
authors.affiliation: USC Voice Center, University of Southern California, Los Angeles, California.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Johns
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D005260:Female; D019416:Head Movements; D006801:Humans; D008297:Male; D010699:Phonation; D011187:Posture; D012649:Self Concept; D013061:Speech Acoustics; D013068:Speech Production Measurement; D013997:Time Factors; D014833:Voice Quality
keywords: mechanisms; posture; vocal effort; vocal fatigue; voice disorders