Researchers evaluating methods to identify epilepsy for large-scale epidemiological and genetic studies have published findings on a nine-question telephone screening instrument, according to data from a population-based study utilizing resources from the Rochester Epidemiology Project. Published in Cureus under the title “Validation of the Indonesian Brief Screening Instrument for Epilepsy,” the study assesses how effectively a brief questionnaire pinpoints individuals with a history of seizures.
Evaluating Sensitivity and False-Positive Rates in Epilepsy Screening
The validated nine-question screening instrument was administered by telephone to 168 individuals with medical record-documented epilepsy—defined as a lifetime history of ≥2 unprovoked seizures—alongside 54 individuals with an isolated unprovoked seizure, and 120 individuals confirmed to be seizure-free through medical record review, according to the study data. Interviewers conducting the telephone calls remained blinded to the record-review findings.
According to the published results, the screening tool achieved a sensitivity of 96% for identifying epilepsy and 87% for detecting isolated unprovoked seizures. Sensitivity measures the proportion of individuals who screened positive among affected individuals. Meanwhile, the false-positive rate—the proportion who screened positive among seizure-free individuals—stood at 7%.
Assuming a lifetime prevalence of 2% in the population, researchers estimated the positive predictive value (PPV) for epilepsy at 23%. This metric indicates that only about one in four screen-positive individuals will be truly affected.
Comparing Single-Question Versus Multi-Question Approaches
The study also analyzed the diagnostic performance of utilizing a single screening question asking whether the subject had ever had epilepsy or a seizure disorder. Relying on this single inquiry yielded markedly different statistical outcomes compared to the full nine-question battery.
According to the findings, the single-question approach produced a sensitivity of 76% and a false-positive rate of 0.8%. However, the estimated positive predictive value for the single question rose to 66%. Researchers noted that subjects with epilepsy were more likely to screen positive using the single question if they were diagnosed after 1964 or continued to have seizures for at least 5 years after diagnosis.
Implications for Epidemiological and Genetic Research
Valid screening questions are critical for identifying affected family members in genetic studies and mapping disease prevalence across populations. Historically, large-scale studies have often relied on two-stage screening strategies. These frameworks deploy an initial broad screen to identify possible cases, followed by detailed assessment to separate true from false positives.
As noted in related historical context cited by researchers, earlier multi-item questionnaires frequently incorporated symptom-based inquiries—such as asking “Have you ever had attacks in which you lose contact with the surroundings?”—to maximize sensitivity, particularly in settings with limited access to medical care. While those broad questionnaires were found to have sensitivity ≥95%, they typically incurred lower specificity, which directly impact the positive predictive value and increase the effort and cost involved in a study.