Background and Purpose A cross-sectional survey is the best method for
determining the prevalence of a chronic condition such as stroke. Bef
ore embarking on a large population study, a valid screening instrumen
t is necessary, This study aimed to validate a self-completion postal
screening questionnaire for assessing lifetime history of stroke. Meth
ods A random sample of 2000 people aged 45 years and over was selected
from the Family Health Services Authority register. A brief self-comp
letion questionnaire requesting self-reported history of stroke was ma
iled to each individual. Responders reporting a history of stroke rece
ived 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-neg
ative responses and assessment of nonresponse bias were documented. Re
sults The response rate for the questionnaire was 88%. Of the sample,
120 (6%) who were wrongly registered were excluded; 173 (10%) of the 1
663 responders reported a history of stroke. The question ''Have you e
ver had a stroke?'' had a sensitivity of 95% and a specificity of 96%.
Conclusions This simple self-completion questionnaire is a valid mean
s of screening for cases of stroke in the community and could form the
basis for subsequent studies of prevalence and health needs.