Supplementary Material for: Development of the Central Africa Daily Functioning Interference Scale for Dementia Diagnosis in Older Adults: The EPIDEMCA Study

Background: There are a few validated tools capable of assessing the dimensions essential for the diagnosis of dementia and cognitive disorders in sub-Saharan Africa. Objectives: Our aim was to develop an adapted tool, the Central African – Daily Functioning Interference (DFI) scale. Methods: An initial 16-item scale of activity limitations and participation restrictions was completed by 301 participants with low cognitive performances to assess their level of DFI. A psychometric evaluation was performed using Item Response Theory. Results: A unidimensional 10-item scale emerged with a reasonable coverage of DFI (thresholds range: –1.067 to 1.587) with good item discrimination properties (1.397–4.076) and a high reliability (Cronbach’s al pha = 0.92). The cutoff for detecting 96% of those with dementia was with a latent score ≥0.035 that corresponds to the LAUNDRY limitation. Conclusions: These results provide valuable support for the reliability and internal validity of an operational 10-item scale for DFI assessment used in Central Africa for the diagnosis of dementia in the elderly.