Adaptation and Validation of Brief Tablet-Based Cognitive Assessment Tool in Uganda

Sub-Saharan Africa (sSA) faces accelerated growth in Alzheimer's disease and related dementias (ADRDs), including in older people living with HIV (PLWH). However, there are limited contextually relevant diagnostic tools to assess cognitive impairment in the region. The Tablet-based Cognitive Assessment Tool (TabCAT) is a digital platform hosting cognitive tests with automated scoring that can be administered by non-specialists and are designed for use across diverse cultures, languages, and education levels. We translated, adapted, and assessed the validity of a brief battery of TabCAT tests in the Uganda Aging and Dementia Cohort Study (UADCS), a prospective cohort of older PLWH and age- and sex-similar adults not living with HIV in southwestern Uganda.

Four TabCAT tests were translated and culturally adapted through expert review and focus groups of adults at study sites. Psychometric validity was examined by assessing floor and ceiling effects, association with known demographic predictors, and concurrent and divergent validity against a reference-standard cognitive testing battery previously validated and employed in Uganda. Z-scores on all tests were derived using a regression-based normative approach to adjust for age, sex, education, urbanicity, and literacy. Receiver Operating Characteristic (ROC) curves were fit to assess the TabCAT Composite Score performance in discriminating objective cognitive impairment (defined using Jak/Bondi criteria) in the total sample, then stratified by HIV serostatus.

TabCAT tests were reported by local experts and focus groups to have acceptable face and content validity. Participants (n=563, mean age 60±6.4, 50% female, 51% did not complete primary school, 16% were not literate, 49% PLWH) completed the reference-standard and TabCAT battery. For TabCAT tests, there were no notable floor or ceiling effects, and test scores were associated with age and education as expected. Correlations between TabCAT and reference-standard tests were stronger in aligning cognitive domains (memory, executive function) than in non-aligning domains (motor). The TabCAT Composite Score discriminated cognitive impairment with good performance (c-statistic 0.77; 95% CI 0.72-0.81), including among PLWH.

TabCAT tests demonstrated face, content, construct, concurrent, and criterion validity for measuring cognition and detecting objective cognitive impairment among older adults in Uganda, including PLWH. These results support the potential of tablet-based brief cognitive assessment tools to measure cognitive performance and detect cognitive impairment in Uganda, including among older PLWH, and in populations with lower levels of education and literacy.