title: Effects of increasing sound pressure level on lip and jaw movement parameters and consistency in young adults.
abstract: OBJECTIVE
  Examination of movement parameters and consistency has been used to infer underlying neural control of movement. However, there has been no systematic investigation of whether the way individuals are asked (or cued) to increase loudness alters articulation. This study examined whether different cues to elicit louder speech induce different lip and jaw movement parameters or consistency.
  
  
  METHODS
  Thirty healthy young adults produced two sentences (a) at comfortable loudness, (b) while targeting 10 dB SPL above comfortable loudness on a sound level meter, (c) at twice their perceived comfortable loudness, and (d) while multitalker noise was played in the background. Lip and jaw kinematics and acoustic measurements were taken.
  
  
  RESULTS
  Each of the loud conditions resulted in a similar amount of SPL increase, about 10 dB. Speech rate was slower in the background noise condition. Changes to movement parameters and consistency (relative to comfortable) were different in the targeting condition as compared to the other loud conditions.
  
  
  CONCLUSIONS
  The cues elicited different task demands, and therefore, different movement patterns were used by the speakers to achieve the target of increased loudness. Based on these results, cueing should be considered when eliciting increased vocal loudness in both clinical and research situations.
authors.affiliation: Department of Speech, Language, and Hearing Sciences, Purdue University, 1353 Heavilon Hall, 500 Oval Drive, West Lafayette, IN 47907-2038, USA. jhuber@purdue.edu
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Huber
authors.forename: Bharath
authors.initials: B
authors.lastname: Chandrasekaran
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008046:Lip / Q000502:physiology*; D008297:Male; D008334:Mandible / Q000502:physiology*; D010700:Phonetics; D011312:Pressure; D013060:Speech / Q000502:physiology*; D013061:Speech Acoustics; D013068:Speech Production Measurement