Validity of a screening instrument for neurologic disability in resource-poor African communities

Background: There have been no recent population-based studies on all-cause adult neurological morbidity in sub-Saharan Africa. We have developed a screening survey to improve the feasibility in performing these studies. Methods: Our screening instrument contains both history questions and examination items. We pilot tested this instrument in the Hai District, Tanzania, and Butajira, Ethiopia using trained individuals from the local communities. To measure sensitivity, we applied the instrument blindly to 25 previously-identified subjects with Parkinson's disease, stroke or epilepsy. To measure specificity, we examined 42 randomly selected previously screened subjects. We also compared the validity of the entire instrument to the history-only section. Results: There were 669 adult subjects screened in both communities (150 screen-positives, and 519 screen-negatives). The sensitivity of the instrument was 100% (95% CI 84.2-100%) and the specificity was 82.4% (95% CI 66.1-92.0%). However, when restricting the instrument to the history-only section, the sensitivity remained unchanged, but the specificity became 91.2% (95% CI 76.3-97.7%; p = 0.48). Conclusions: We have created a valid tool to screen adults for neurologic morbidity in resource-poor communities. The use of the history-only section of the tool is adequate as a screen and will improve feasibility.