Development of a Thai Parkinson's Disease Screening Tool and the Prevalence of Parkinsonism and Parkinson's Disease, Based on a Community Survey in Bangkok

Introduction: Few epidemiological data of parkinsonism and Parkinson's disease (PD) exist in Southeast Asia. We aimed to develop and validate a screening tool, and investigate the prevalence of parkinsonism and PD via a community survey. Methods: A PD-screening tool comprising 11 "yes/no" items was developed in a clinical setting and validated in the community. The prevalence of PD and parkinsonism was investigated in a survey that included PD screening tools, face-to-face interviews, and physical examinations. Receiver operating characteristic curves were constructed for a range of cutoff points to explore the screening tool's sensitivity and specificity. Results: Of 1,846 participants surveyed, the mean age was 64.4 ± 8.0 years. The age-standardized prevalence of parkinsonism was 1,954 per 100,000 people, and that of PD was 706. Of 36 parkinsonism cases, 13 were PD, 13 were vascular parkinsonism, 8 were drug-induced parkinsonism, and 2 were head-injury related. Three cases were previously diagnosed with PD. A cutoff score of 5 on the screening tool showed a sensitivity of 98%, a specificity of 94%, and positive and negative likelihood ratios of 16.33 and 0.02, respectively. The area under the curve was 0.985. Conclusions: The prevalence of parkinsonism and PD in Thailand is similar to that in Western countries but slightly higher than that for other Asian countries. Differing methodologies, diagnostic criteria, and case identification strategies may contribute to variations in the reported prevalence of PD. Widespread use of the Thai PD-screening tool should be implemented to facilitate early detection of new cases and, in turn, better healthcare.