title: Reliability and construct validity of the Spanish version of the 6-item CTS symptoms scale for outcomes assessment in carpal tunnel syndrome.
abstract: BACKGROUND
  The purpose of this study was to assess the reliability and construct validity of the Spanish version of the 6-item carpal tunnel syndrome (CTS) symptoms scale (CTS-6).
  
  
  METHODS
  In this cross-sectional study 40 patients diagnosed with CTS based on clinical and neurophysiologic criteria, completed the standard Spanish versions of the CTS-6 and the disabilities of the arm, shoulder and hand (QuickDASH) scales on two occasions with a 1-week interval. Internal-consistency reliability was assessed with the Cronbach alpha coefficient and test-retest reliability with the intraclass correlation coefficient, two way random effect model and absolute agreement definition (ICC2,1). Cross-sectional precision was analyzed with the Standard Error of the Measurement (SEM). Longitudinal precision for test-retest reliability coefficient was assessed with the Standard Error of the Measurement difference (SEMdiff) and the Minimal Detectable Change at 95 % confidence level (MDC95). For assessing construct validity it was hypothesized that the CTS-6 would have a strong positive correlation with the QuickDASH, analyzed with the Pearson correlation coefficient (r).
  
  
  RESULTS
  The standard Spanish version of the CTS-6 presented a Cronbach alpha of 0.81 with a SEM of 0.3. Test-retest reliability showed an ICC of 0.85 with a SRMdiff of 0.36 and a MDC95 of 0.7. The correlation between CTS-6 and the QuickDASH was concordant with the a priori formulated construct hypothesis (r 0.69) CONCLUSIONS: The standard Spanish version of the 6-item CTS symptoms scale showed good internal consistency, test-retest reliability and construct validity for outcomes assessment in CTS. The CTS-6 will be useful to clinicians and researchers in Spanish speaking parts of the world. The use of standardized outcome measures across countries also will facilitate comparison of research results in carpal tunnel syndrome.
authors.affiliation: Unit for Hand & Microsurgery, GECOT, La Laguna, Tenerife, Spain. titorosales@telefonica.net.
authors.forename: Roberto S
authors.initials: RS
authors.lastname: Rosales
authors.affiliation: Department of Orthopedics, University Hospital of La Candelaria, Santa Cruz de Tenerife, Spain. ymartinhidalgo@gmail.com.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Martin-Hidalgo
authors.affiliation: Department of Orthopedics, University Hospital of La Candelaria, Santa Cruz de Tenerife, Spain. lrebmor@gmail.com.
authors.forename: Luis
authors.initials: L
authors.lastname: Reboso-Morales
authors.affiliation: Departments of Clinical Sciences, Lund University, Lund, Sweden. Isam.Atroshi@med.lu.se.|Orthopedics Hässleholm-Kristianstad, Hässleholm Hospital, Hässleholm, Sweden. Isam.Atroshi@med.lu.se.
authors.forename: Isam
authors.initials: I
authors.lastname: Atroshi
mesh_terms: D000328:Adult; D000368:Aged; D002349:Carpal Tunnel Syndrome / Q000150:complications / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013030:Spain; D011795:Surveys and Questionnaires