title: The relative and absolute reliability of maximum phonation time in community-dwelling Japanese people.
abstract: OBJECTIVE
  The aim of the present study was to examine the approximate value of maximum phonation time in community-dwelling Japanese people and to set the range of error after ascertaining relative and absolute reliability.
  
  
  METHODS
  Participants in the present study were adults living in Kobe and Himeji City, Hyogo Prefecture, Japan. Participants were seated in the upright sitting position and were asked to produce an /a/ sound at their normal speaking volume for as long as they possibly could. The examiner measured the time until the sound became inaudible. Two trials were performed.
  
  
  RESULTS
  The subjects in the final analysis comprised 380 adults (246 women, 134 men; age, 72.7 ± 5.9 years). The values of trial 1 and trial 2 were analyzed with intraclass correlation coefficient (ICC(1,1)), and Bland-Altman plot. Average values of the women, men, and both sexes combined were 16.1, 18.7, and 17.0 s, respectively. Average values of age groups 60-69, 70-79, and 80-89 years were 17.9, 16.8, and 15.9 s, respectively. The ICC(1,1)was 0.87 (P < 0.001). Both fixed bias and proportional bias existed. Limits of agreement (LOA) were -5.0 to 7.7 and % change ranged from -27.1 to 41.8 %.
  
  
  CONCLUSIONS
  These normative data indicated that sufficiently reliable values could be measured in two trials. LOA showed that the second value tended to be higher. In determining the effect of treatment, one must consider that the value will be slightly higher at re-test.
authors.affiliation: Department of Physical Therapy, Faculty of Health Sciences, Kobe University School of Medicine, Kobe, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Shinoda
authors.affiliation: Department of International Health Sciences, Kobe University Graduate School of Health Sciences, 10-2 Tomogaoka 7-chome Suma, Kobe, 654-0142, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Kanai
authors.affiliation: Department of Community Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Nakamura
authors.affiliation: Department of Community Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Murata
authors.affiliation: Department of Community Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Saito
authors.affiliation: Department of Community Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Sawa
authors.affiliation: Department of Community Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Japan.
authors.forename: Rei
authors.initials: R
authors.lastname: Ono
authors.affiliation: Department of International Health Sciences, Kobe University Graduate School of Health Sciences, 10-2 Tomogaoka 7-chome Suma, Kobe, 654-0142, Japan. izawapk@harbor.kobe-u.ac.jp.
authors.forename: Kazuhiro P
authors.initials: KP
authors.lastname: Izawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010699:Phonation / Q000502:physiology*; D015203:Reproducibility of Results; D057566:Self Report; D013997:Time Factors
keywords: Absolute reliability; Community-dwelling people; Maximum phonation time; Relative reliability