title: Reliability, validity, and responsiveness of the Japanese version of the Patient-Specific Functional Scale in patients with neck pain.
abstract: OBJECTIVE
  The aims of this study were to translate and culturally adapt the Patient-Specific Functional Scale (PSFS) and validate the Japanese version of the PSFS (PSFS-J) in outpatients with neck pain.
  
  
  METHODS
  The PSFS was translated and adapted into Japanese in accordance with the published guidelines. A total of 103 outpatients with neck pain were recruited for this study. Psychometric evaluation included test-retest reliability, convergent validity by comparing the PSFS-J to the Neck Disability Index (NDI), patient's global impression of change (PGIC), and responsiveness (unpaired t test, minimal detectable change).
  
  
  RESULTS
  The intraclass correlation coefficient for test-retest reliability was 0.98 (95% confidence interval = 0.95-0.99). The Pearson correlation coefficient with the NDI was -0.35. The Spearman correlation coefficient showed a strong relationship between the change score in the PSFS-J and PGIC (-0.70). The analysis of responsiveness was calculated with the unpaired t test showing a significant difference between the stable and improved patients (P < 0.01). The minimal detectable change was calculated as 0.64.
  
  
  CONCLUSIONS
  The Japanese version of the PSFS is a valid, reliable, and responsive instrument to assess Japanese outpatients with neck pain.
authors.affiliation: Department of Rehabilitation Medicine, Terashima Orthopaedic Clinic, 3-33-10 Nishiooizumi Nerima-ku, Tokyo, 178-0065, Japan. koji.nakamaru@nifty.com.|Graduate School of Human Health Science, Tokyo Metropolitan University, Tokyo, Japan. koji.nakamaru@nifty.com.
authors.forename: Koji
authors.initials: K
authors.lastname: Nakamaru
authors.affiliation: Athletic Rehabilitation Section, Clinical Center for Sports Medicine and Sports Dentistry Sports Science Organization, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Aizawa
authors.affiliation: Department of Physical Education, Nihon University, Tokyo, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Koyama
authors.affiliation: Graduate School of Human Health Science, Tokyo Metropolitan University, Tokyo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Nitta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000503:physiopathology*; D011594:Psychometrics; D015203:Reproducibility of Results; D014175:Translating; D055815:Young Adult
keywords: Cultural adaptation; Neck pain; Psychometric testing; The Patient-Specific Functional Scale