title: Validation of a population screening questionnaire to assess prevalence of stroke.
abstract: OBJECTIVE
  A cross-sectional survey is the best method for determining the prevalence of a chronic condition such as stroke. Before embarking on a large population study, a valid screening instrument is necessary. This study aimed to validate a self-completion postal screening questionnaire for assessing lifetime history of stroke.
  
  
  METHODS
  A random sample of 2000 people aged 45 years and over was selected from the Family Health Services Authority register. A brief self-completion questionnaire requesting self-reported history of stroke was mailed to each individual. Responders reporting a history of stroke received a request for a standardized home assessment visit. Confirmation of the diagnosis of stroke was made based on information from the home visit together with multiple sources of case ascertainment. False-negative responses and assessment of nonresponse bias were documented.
  
  
  RESULTS
  The response rate for the questionnaire was 88%. Of the sample, 120 (6%) who were wrongly registered were excluded; 173 (10%) of the 1663 responders reported a history of stroke. The question "Have you ever had a stroke?" had a sensitivity of 95% and a specificity of 96%.
  
  
  CONCLUSIONS
  This simple self-completion questionnaire is a valid means of screening for cases of stroke in the community and could form the basis for subsequent studies of prevalence and health needs.
authors.affiliation: Department of Medicine, University of Newcastle, Newcastle upon Tyne, UK.
authors.forename: P G
authors.initials: PG
authors.lastname: O'Mahony
authors.forename: R
authors.initials: R
authors.lastname: Dobson
authors.forename: H
authors.initials: H
authors.lastname: Rodgers
authors.forename: O F
authors.initials: OF
authors.lastname: James
authors.forename: R G
authors.initials: RG
authors.lastname: Thomson
mesh_terms: D000368:Aged; D002561:Cerebrovascular Disorders / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D015995:Prevalence; D012042:Registries; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires