Cognitive decline assessment in speakers of understudied languages

Projected trends in population aging have forecasted a massive increase in the number of people with dementia, in particular in sub-Saharan Africa and the Middle East and North Africa (MENA) region. Cognitive decline is a significant marker for dementia, typically assessed with standardized neuropsychological tools that have been validated in some well-researched languages such as English. However, with the existing language diversity, current tools cannot cater to speakers of understudied languages, putting these populations at a disadvantage when it comes to access to early and accurate diagnosis of dementia. Here, we shed light on the detrimental impact of this language gap in the context of the MENA region, highlighting inadequate tools and an unacceptable lack of expertise for a MENA population of a half billion people. Our perspective calls for more research to unravel the exact impact of the language gap on the quality of cognitive decline assessment in speakers of understudied languages. Highlights: Cognitive decline is a marker for dementia, assessed with neuropsychological tests. There is a lack of culturally valid tests for speakers of understudied languages. For example, suboptimal cognitive tests are used in the Middle East and North Africa region. Linguistic diversity should be considered in the development of cognitive tests.