title: Development of a reliable self-report outcome measure for pragmatic trials of communication therapy following stroke: the Communication Outcome after Stroke (COAST) scale.
abstract: OBJECTIVE
  To develop and validate a clinically feasible measure of communication effectiveness for people with any type of communication problem following stroke.
  
  
  METHODS
  Cross-sectional, interview-based, psychometric study, building on the development phase for construction of the Communication Outcome after Stroke (COAST) scale.
  
  
  METHODS
  A community sample from the northwest of England, UK.
  
  
  METHODS
  One hundred and two people with communication problems (aphasia and/or dysarthria) following a stroke, within the previous 4-12 months.
  
  
  METHODS
  Administration of the COAST scale, on two occasions, within a two-week period, and collection of demographic and other data relating to disability, degree of aphasia (where appropriate) and hospital diagnosis of aphasia/dysarthria.
  
  
  METHODS
  Acceptability (missing values), reliability (internal consistency and test-retest reliability) and item analysis (item redundancy).
  
  
  RESULTS
  Ninety-seven (visit 1) and 98 (visit 2) respondents provided usable data for the psychometric analysis. The 29-item COAST scale showed good acceptability (few missing values, sample spread 28-100%), internal consistency and test-retest reliability for the scale (alpha = 0.95; ICC = 0.90) and its subscales (alpha = 0.65-0.93; ICC = 0.72-0.88), but possible item redundancy. A revised scale of 20 items was produced, demonstrating good internal consistency and test-retest reliability (alpha = 0.83-92; ICC = 0.72-0.88).
  
  
  CONCLUSIONS
  The COAST is a patient-centred, practical and reliable measure that can be used to assess self-perceived communication effectiveness for people with aphasia and/or dysarthria. Further testing on construct validity and responsiveness to change is needed before the measure can be firmly recommended for use within clinical practice and research.
authors.affiliation: University of Leeds, School of Healthcare, Leeds, UK. a.f.long@leeds.ac.uk
authors.forename: Af
authors.initials: A
authors.lastname: Long
authors.forename: A
authors.initials: A
authors.lastname: Hesketh
authors.forename: G
authors.initials: G
authors.lastname: Paszek
authors.forename: M
authors.initials: M
authors.lastname: Booth
authors.forename: A
authors.initials: A
authors.lastname: Bowen
mesh_terms: D000328:Adult; D000368:Aged; D003147:Communication Disorders / Q000175:diagnosis* / Q000209:etiology*; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D020521:Stroke / Q000150:complications*; D055815:Young Adult