Validation of a brief screening instrument for the ascertainment of epilepsy

Ruth Ottman, Christie Barker-Cummings, Cynthia L. Leibson, Vincent M. Vasoli, W. Allen Hauser, Jeffrey R. Buchhalter

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

Purpose: To validate a brief screening instrument for identifying people with epilepsy in epidemiologic or genetic studies. Methods: We designed a nine-question screening instrument for epilepsy and administered it by telephone to individuals with medical record-documented epilepsy (lifetime history of ≥2 unprovoked seizures, n = 168) or isolated unprovoked seizure (n = 54), and individuals who were seizurefree on medical record review (n = 120), from a population-based study using Rochester Epidemiology Project resources. Interviewers were blinded to record-review findings. Results: Sensitivity (the proportion of individuals who screened positive among affected individuals) was 96% for epilepsy and 87% for isolated unprovoked seizure. The false positive rate (FPR, the proportion who screened positive among seizure-free individuals) was 7%. The estimated positive predictive value (PPV) for epilepsy was 23%, assuming a lifetime prevalence of 2% in the population. Use of only a single question asking whether the subject had ever had epilepsy or a seizure disorder resulted in sensitivity 76%, FPR 0.8%, and estimated PPV 66%. Subjects with epilepsy were more likely to screen positive with this question if they were diagnosed after 1964 or continued to have seizures for at least 5 years after diagnosis. Discussion: Given its high sensitivity, our instrument may be useful for the first stage of screening for epilepsy; however, the PPV of 23% suggests that only about one in four screen-positive individuals will be truly affected. Screening with a single question asking about epilepsy yields a higher PPV but lower sensitivity, and screen-positive subjects may be biased toward more severe epilepsy.

Original languageEnglish (US)
Pages (from-to)191-197
Number of pages7
JournalEpilepsia
Volume51
Issue number2
DOIs
StatePublished - Feb 5 2010

Keywords

  • Epidemiology
  • Epilepsy
  • Questionnaire
  • Sensitivity
  • Specificity
  • Validity

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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    Ottman, R., Barker-Cummings, C., Leibson, C. L., Vasoli, V. M., Hauser, W. A., & Buchhalter, J. R. (2010). Validation of a brief screening instrument for the ascertainment of epilepsy. Epilepsia, 51(2), 191-197. https://doi.org/10.1111/j.1528-1167.2009.02274.x