A Single Question about Prior Stroke versus a Stroke Questionnaire to Assess Stroke Prevalence in Populations

Abstract

Background: False-positive and false-negative answers to screening questions influence prevalence and incidence estimations for stroke in population studies. Despite frequent use in screening, only a few studies have examined causes and influence of incorrect self-reports. We compared the rates of false-positive and false-negative answers to a single question about prior stroke to those of the Stroke Symptom Questionnaire (SSQ), a newly developed instrument based on 6 symptom questions. Differences in stroke prevalence estimations and risk factors for incorrect reports are described. Methods: The MEMO study (Memory and Morbidity in Augsburg Elderly) examines cognitive function and neurodegenerative diseases in an elderly population (n = 384) in southern Germany. All participants filled in the symptom questionnaire, received a neurological examination and a neuropsychological test battery. Medical records were obtained for event validation of subjects positive on screening and those negative on screening with symptoms suggesting a cerebrovascular event during examination. Results: Prevalence of total stroke was 5.3% using a single screening question and 6.8% using the questionnaire. The false-negative rate was higher for the single-question approach (34.2 versus 10.5%). It was strongly influenced by gender and cognitive function. The questionnaire had a higher false-positive rate than the single question. Based on the results, we established question combinations that best served three different research scenarios (frequency estimation, risk factor analysis, control selection), relevant to stroke research in population studies. Conclusions: A single screening question for stroke in the past with event validation by medical records underestimates stroke frequency in population studies by about 30%. Use of a number of questions for key symptoms combined with a general stroke question, as in the SSQ, improves the completeness of event ascertainment and allows the detection of stroke and transient ischemic attack at the same time.

Validating the Questionnaire for Verifying Stroke-Free Status (QVSFS) by Neurological History and Examination

“…The purpose of the QVSFS, to identify individuals who are free of stroke/TIA, is most consistent with the strategy of selecting proper controls suggested by Berger et al 19 For this strategy they used 2 questions about impairment of vision and a question about previously diagnosed stroke, which resulted in a sensitivity of 84.2%, moderately lower than the overall sensitivity of 97% for the QVSFS. Another potential use of the QVSFS, given the low negative likelihood ratio of 0.04, is to assist in case ascertainment of subjects with stroke by efficiently reducing the number of subjects requiring a comprehensive medical record review and/or examination.…”

Prevalence and Associated Factors of Silent Brain Infarcts in a Mediterranean Cohort of Hypertensives

“…25 Also, when dementia was suspected, following Diagnostic and Statistical Manual of Mental Disorders, fourth edition, revised (DSM-IV-R) criteria, the patient was not included in the study and a proper evaluation in the presence of a caregiver was recommended. 26 Enrollment visits were conducted between November 2010 and May 2012.…”

B Vitamin Plasma Levels and the Risk of Ischemic Stroke and Transient Ischemic Attack in a German Cohort

“…In addition, they had to answer a question about cerebral ischemia at the first follow-up and to specify stroke symptoms in the second follow-up questionnaire. 16 Subsequent validation of selfreported strokes and TIAs was based on medical records and followed an established protocol that included a standardized form filled in by the treating physician or the study physician. 17 We have previously reported on the incidence rate of stroke in this cohort, which roughly resembles the incidence usually observed in the general population of the respective age group in Germany.…”