SELECTION OF CULTURE-FAIR COGNITIVE TOOLS FOR CLINICAL DEMENTIA SCREENING IN ETHNICALLY DIVERSE POPULATIONS: A FOCUS ON SUB-SAHARAN AFRICA

Abstract

The growing rate of dementia in sub-Saharan Africa (SSA) is of great diagnostic concern because of the cultural diversities, differences in literacies and validation of the cognitive screening devices. The current systematic review focuses on culture-fair cognitive assessment devices applicable in screening dementia in ethnically diverse groups, especially focusing on SSA. When 31 studies have been thoroughly analyzed, it can be seen that there is a wide range of heterogeneity in the aspects of developing tools, their validation, and their performance in different settings. The main conclusions are that even though tools like the Rowland Universal Dementia Assessment Scale (RUDAS), the Identification and Intervention for Dementia in Elderly Africans (IDEA) cognitive screen, and the Community Screening Instrument for Dementia (CSI-D) have potential in low-literate populations, much of the work remains in unifying validation, normalization, and cross-cultural adaptation. Most traditional screening tools are biased towards education, and few tools have managed to show actual culture-fairness. This literature review has established key priorities of future research, such as necessities in the development of context-specific tools, intensive validation research among diverse people in Africa, and standardized methods of adaptation. The implications of these findings for clinical practice, research, and policy development in resource-limited environments where the burden of dementia is rapidly rising are significant.
Keywords: Dementia screening, culture-fair test, cognitive instrument, sub-Saharan Africa, cross-cultural validation, literacy bias.

Introduction

Background and Rationale
Dementia is one of the most serious international health problems of the 21st century, and the conceptual consequences of the issue are overwhelming both to the healthcare systems, families, and even to the whole world. Dementia epidemiology in sub-Saharan Africa has some peculiarities that are not comparable with those of the high-income nations. The prevalence rates are quite different in the region, with a range of 2.29% to 21.60%, indicating not only actual epidemiological diversity but also methodological differences, as well as a lack of sufficient screening tools (Olayinka & Mbuyi, 2014). Such a large range of variation highlights some of the underlying issues related to the accurate identification and diagnosis of dementia in populations with remarkable cultural and linguistic diversity, educational achievement differences, and access to advanced neurological care.
The demographic transition experienced throughout SSA, which is marked by a longer life expectancy and population ageing, is expected to lead to significant growth in the number of cases of dementia in the next few decades (Akinyemi et al. 2021). Nevertheless, the state of affairs on the continent is quite paradoxical: as the prevalence of dementia is on the increase, the diagnosis, care, and research infrastructure is in an abysmal state. Such a difference is additionally complicated by the lack of robustness in cognitive screening instruments that have been largely created and validated among the population of Western, educated, industrialized, rich, and democratic (WEIRD) people (Gangaram-Panday et al. 2023). Use of such tools in non-WEIRD populations, especially in SSA, raises some fundamental questions of diagnostic validity, cultural appropriateness, and clinical applicability.
The Challenge of Cultural Fairness in Cognitive Assessment
Culturalfairness. It is more than the translation of existing instruments into other languages. It involves a complicated interaction between cognitive concepts, cultural background, educational history, and linguistic multiplicity (Chithiramohan et al. 2024). Conventional tools of cognitive screening, like Mini-Mental State Examination (MMSE), were constructed based on the assumptions regarding education exposure, literacy, and cultural knowledge, which might not work in different populations of the world. The studies have also continued to show that the use of these traditional tools is highly biased in education and culture, which contributes to the high phenomenon of false positives in lowly educated individuals (Chin et al. 2011).
This is especially central in SSA, with literacy levels significantly intermittent, formal education possible or not, and cultural conceptualizations and understanding of cognitive health significantly different than Western ones (Sweetland et al. 2013). Moreover, the continent has over 54 countries with thousands of diverse languages, which pose a significant barrier to standardized testing. Diversity of regional and ethnic background is high even within countries, which argues the need to pay significant attention to the way cognitive constructs are operationalized and quantified (Guerchet et al. 2017).
The Sub-Saharan African Context
Sub-Saharan Africa is a specific epidemiological as well as sociocultural environment regarding dementia research and clinical care. The area is extremely diversified in terms of ethnicities, languages, cultures, education systems, and healthcare facilities. The different developmental paths and the political historical developments, such as the colonial past, have given rise to diverse levels of educational achievements and health literacy (Mavrodaris et al. 2013). Such contextual variables have a significant effect on how cognitive impairment is presented, as well as the effectiveness of assessment instruments.
It has been challenging to determine the incidence of dementia in SSA with any accuracy, partially because of the methodology differences among studies and the feasibility of screening tools available. Prevalence estimates based on DSM-IV criteria are as high as 6.4%, and the 10/66 dementia criteria as high as 21.6% estimates, showing the enormous effect of diagnostic techniques on prevalence estimates (Paddick et al. 2013). This variation is not an issue of academic interest only; it has its own direct impact on the allocation of resources, service planning, and policy development, which has implicit implications.
Besides, the risk factor profile between dementia and that in high-income nations might vary. Although the role of cardiovascular risk factors seems to be significant, the impact of infectious diseases, nutritional factors, and environmental exposures is not properly defined (Akinyemi et al. 2021). Also, the interaction of HIV/AIDS with cognitive impairment has specific issues regarding screening and diagnosis in the region, and these problems need to be addressed through tools that can distinguish between HIV-associated neurocognitive disorders (HAND) and other types of dementia (Mwangala et al. 2019).
Objectives of This Review
This systematic review seeks to critically review the culture-fair cognitive screening instruments landscape that is appropriate in the assessment of dementia in ethnically diverse populations, especially the applicability as well as validation of these instruments in the sub-Saharan Africa setting. The specific objectives are:
To determine and describe those cognitive screening instruments that have been created or proven to be used with culturally diverse, low-literacy groups.
To determine the psychometric quality of these instruments, diagnostic quality, and cultural suitability.
To review the quality and the magnitude of validation research studies in sub-Saharan African communities.
To detect a gap in existing knowledge and practice.
To make evidence-based recommendations in choosing the tools during clinical and research environments.

Methods

Search Strategy and Selection Criteria
The current systematic review is a synthesis of the results of various published systematic reviews and primary studies that focus on cognitive screening tools in various populations. The selected studies were identified on the basis of their opportunity to relate to culture-fair assessment, validation in low-literacy groups, and use in sub-Saharan African settings. The included studies had to be: (1) studies that investigated cognitive screening tools in dementia or mild cognitive impairment; (2) studies that addressed the issues of cultural fairness, educational bias, or cross-cultural validation; (3) those studies that reported the validation studies of ethnically diverse or low-literacy populations; (4) and studies that reported a validation study of sub-Saharan African population.
Quality Assessment
This meant that the quality of the included studies was reviewed using predefined criteria, including references to studies on diagnostic accuracy, and the quality of these studies was determined by reviewing the study design, sampling, reference standards, study blinding, and statistical tests. Specific emphasis was placed on such methodological characteristics that can be applied in terms of cultural validity as translation and adaptation processes, the presence of different levels of education, and the evaluation of the different working of items across cultural groups.
Data Extraction and Synthesis
Information was lifted on the nature of tools (Items, time of administration, domains, domains to be measured, validation samples (setting, country, educational characteristics), psychometric characteristics (reliability, validity, diagnostic accuracy), and pragmatic (training needs, administration format). Due to the heterogeneity of included studies and populations, a narrative synthesis model was selected, and quantitative data were demonstrated where necessary.
Results
Overview of Identified Cognitive Screening Tools
The literature review was conducted systematically, which revealed a wide range of cognitive screening instruments that have been developed or adapted to be used in culturally diverse populations. Giaquinto et al. (2022) have discovered 42 articles that investigated 30 different touchscreen-administrable cognitive tools and batteries. Nevertheless, they discovered that a small number of these tools were cross-culturally and cross-linguistically validated (7 tools) and that only two of them, IDEA cognitive screen and the mSTS-MCI, were cross-culturally and cross-linguistically validated in low-educated groups. Most importantly, the IDEA cognitive screen became the sole instrument, which was developed and tested to be used in the sub-Saharan African context.
In the study by Chithiramohan et al. (2024), the systematic review of the literature covered culture-fair cognitive screening tools and analyzed 28 studies to evaluate eleven different instruments. Their study found a significant difference in the applicability and performance of the given tools among different populations. The most researched were the Rowland Universal Dementia Assessment Scale (RUDAS), the Montreal Cognitive Assessment (MoCA), the Community Screening Instrument of dementia (CSI-D), the Visual Cognitive Assessment Test (VCAT), and the Kimberley Indigenous Cognitive Assessment (KICA).
Rowland Universal Dementia Assessment Scale (RUDAS)
RUDAS has become one of the most promising culture-fair screening instruments, with widespread validation in various groups. Naqvi et al. (2015) performed a systematic review and meta-analysis of the RUDAS performance in a multicultural population, with a pooled sensitivity of 77.2% (95% CI 67.4-84.5%) and a pooled specificity of 85.9% (95% CI 74.892.6). The positive likelihood ratio was 5.5 (95%CI 2.9-10.7), and the negative likelihood ratio was 0.27 (95%CI 0.17-40), which represented good discriminatory power. Notably, the RUDAS showed a very good correlation with MMSE (r = 0.77, 95% CI 0.72-0.81) and is much less influenced by language and education level.
According to Chithiramohan et al. (2024), RUDAS has similar performance to the MMSE with excellent specificity of 0.62-0.93, sensitivity of 52-94%, and specificity of 70-98 in the studies. The instrument proved to be better than the MMSE in the screening of dementia among ethnic minorities and was reported to be little affected by the level of education. These results put RUDAS in a unique position as a resource that can be seriously useful for people with a mixed population in terms of their educational backgrounds. Akinyemi et al. (2021) indicated in particular that RUDAS has been demonstrated to be a valid instrument in screening dementia in Arabic-speaking communities, but sub-Saharan African validation has not been done extensively.
The Identification and Intervention for Dementia in Elderly Africans (IDEA) Cognitive Screen
The IDEA cognitive screen is the most critical change in culture-fair screening of dementia, which was specifically designed to address the sub-Saharan African populations. Gray et al. (2014) have explained how this instrument was developed and preliminarily justified in Tanzania. The instrument was skewed towards reducing educational and cultural bias and high diagnostic accuracy. The five-item first version had an AUROC of 0.871 with a sensitivity of 91.7% and a specificity of 61.7%. In prospective testing, the five-item-instrument yielded an AUROC of 0.867, and could be used within less than ten minutes. A matchstick design item added with a matchstick design item has enhanced performance to an AUROC of 0.888, which led to the final six-item instrument.
The IDEA cognitive screen has proved to be a strong and effective instrument in various African environments, as subsequently validated in study findings. The instrument was demonstrated by Paddick et al. (2015) to have excellent discriminatory power in Nigeria (AUROC 0.990) and Tanzania (AUROC 0.919) in outpatients and inpatients, respectively. Inter-rater reliability of the tool (ICC 0.742 to 0.791) was good, and internal consistency (Cronbach 0.738 to 0.807) was satisfactory with different samples. More importantly, the IDEA cognitive screen not only did not show any educational bias but also could effectively be administered by nonspecialist medical staff, which is important concerning the practical aspects of the situation in most African countries where specialist numbers are limited.
The areas that receive measurement on the IDEA cognitive screen are orientation, memory (immediate and delayed recall), and visuospatial construction in the form of the matchstick design task. The simplicity and shortness of the instrument render it rather effective to be applied in the context of resource-deprived conditions where long-term tests might not be viable. Giaquinto et al. (2022) also highlighted that the IDEA screen is the only tool that was specifically designed and validated to use in sub-Saharan Africa, which is important in determining a profound absence in the tools available in the area.
Community Screening Instrument for Dementia (CSI-D)
CSI-D was also specifically written to be used in environments where formal education is low, and thus it can be quite applicable in most African contexts. Prince et al. (2010) provided a cross-cultural derivation and validation of a short form of the CSI-D and found high psychometric qualities in different groups of patients. The short cognitive scale, which entails the ability to describe the use of common objects, name body parts, and delayed recall, had an overall range of 0.88 to 0.92 in terms of the value of AUROC. The short informant scale, which included items regarding functional impairment and memory problems, also showed better results with the values of 0.92 to 0.97 in terms of the use of the informant.
Diagnostic accuracy was further enhanced when cognitive scales were combined with the informant scales, with the values of the AUROC between 0.94 and 0.99. The sensitivity of mild dementia was 69.2% and rose to 82.8% with moderate dementia. Specificity was marginally decreasing with low-education controls than with high-education controls, and the tool ensured a decent performance rate in both educational levels. The study by Chithiramohan et al. (2024) found that educational level did not have a significant impact on the CSI-D, which indicates that it is a culture-fair instrument.
Akinyemi et al. (2021) recognized one of the most powerful tools to be used to screen dementia in the African context, CSI-D, which is developed to address the low-education segment of the population. This dual-component design using direct cognitive assessment and informant report resolves one significant problem facing dementia screening: the combination of objective measures of performance, as well as functional observation. Nevertheless, Guerchet et al. (2017) concluded that the informant reports turned out to be more culturally varied as compared to cognitive tests in the sub-Saharan African populations, which implied that this aspect might need special attention.

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