Demographically-adjusted normative data for Symbol Digit Modalities Test (SDMT) among Sri Lankan adults

Background: Symbol Digit Modalities Test (SDMT) is a simple pencil-and-paper substitution task that measures divided attention, visual scanning and processing speed. It sensitive to cognitive impairment in wide variety of neuropsychiatric conditions. Extant normative data for the SDMT, mainly based on Western populations, may not be applicable Sri Lankans. 
 Aims: We aimed create sex-, age- education-adjusted regression-based norms SDMT Lankan adults.
 Methods: Four-hundred twenty-two community-living adults (220 women, 52.1%), aged 18 83 years, with 5 23 years education, completed study. conducted multiple linear regression analyses sex, age education predict score. Results: The scores sample ranged from 72, mean (SD) score 35.98 (12.87). model [predicted = 29.395 - (1.549 × sex) (0.434 years) + (2.207 education)] explained 56.5% variance (adjusted R2 0.565; F=183; p