A screening questionnaire for convulsive seizures: A three-stage field-validation in rural Bolivia

Abstract

IntroductionEpilepsy is one of the most common neurological diseases in Latin American Countries (LAC) and epilepsy associated with convulsive seizures is the most frequent type. Therefore, the detection of convulsive seizures is a priority, but a validated Spanish-language screening tool to detect convulsive seizures is not available. We performed a field validation to evaluate the accuracy of a Spanish-language questionnaire to detect convulsive seizures in rural Bolivia using a three-stage design. The questionnaire was also administered face-to-face, using a two-stage design, to evaluate the difference in accuracy.MethodsThe study was carried out in the rural communities of the Gran Chaco region. The questionnaire consists of a single screening question directed toward the householders and a confirmatory section administered face-to-face to the index case. Positive subjects underwent a neurological examination to detect false positive and true positive subjects. To estimate the proportion of false negative, a random sample of about 20% of the screened negative underwent a neurological evaluation.Results792 householders have been interviewed representing a population of 3,562 subjects (52.2% men; mean age 24.5 ± 19.7 years). We found a sensitivity of 76.3% (95% CI 59.8–88.6) with a specificity of 99.6% (95% CI 99.4–99.8). The two-stage design showed only a slightly higher sensitivity respect to the three-stage design.ConclusionOur screening tool shows a good accuracy and can be easily used by trained health workers to quickly screen the population of the rural communities of LAC through the householders using a three-stage design.

A screening questionnaire for generalized tonic‐clonic seizures: Hospital‐based validation vs field‐validation method

“…However, it did not reach the levels of accuracy usually obtained by other questionnaires that have been validated in a hospital‐based context . The objective of the present study was to perform a hospital‐based validation of the screening questionnaire developed by our group and to compare the levels of accuracy obtained for the same questionnaire when validated in the field or in a hospital‐based context.…”

“…Therefore, to avoid selection bias, a screening tool should be validated in the general population. However, field validations are cost and time consuming because the screening questionnaire should be administered in a large sample of the population and, in order to detect false negative subjects, at least an appropriate random sample of screened negative subjects should also undergo a neurologic examination in the second phase . This kind of validation provides more accurate estimates but is difficult to perform, above all in rural settings where the population is spread in large areas and specialists are rarely available to confirm the diagnosis.…”

“…We used the screening tool already field‐validated by our group in the rural communities of Chaco region in Bolivia . The questionnaire is a modified and translated version of the questionnaire developed by Anand et al .…”

“…Subjects answering YES to the first screening question were considered to be positive. The more‐specific features of the questionnaire have been described elsewhere …”

“…We recently developed and field‐validated a screening tool to specifically detect generalized tonic‐clonic seizures (GTCS) . Our screening questionnaire was validated in the general population of the rural communities in the Chaco region of Bolivia, using a field‐validation design.…”