Cognitive Screening Instruments for Older Adults with Low Educational and Literacy Levels: A Systematic Review

Abstract

This study presents a systematic review on existing cognitive screening tools for mild cognitive impairment and dementia in populations with low education and literacy levels. Cochrane Library, PubMed and LILACS databases were examined for studies including adults aged 50 years old or older with low educational level. 61 articles were included. Despite its frequent use, studies on Mini-Mental State Examination (MMSE) revealed that educational level biased the score obtained, regardless of other factors. Separately, the Informant Questionnaire on Cognitive Decline in the Elderly, the Fototest, or the Eurotest, appear to minimize the effect of education and literacy. MMSE is unreliable for individuals with low literacy. Tasks involving reading, writing, arithmetics, drawing, praxis, visuospatial, and visuoconstructive skills have a greater educational bias than naming, orientation, or memory. An adequate determination of educational level and validation of instruments in populations with heterogeneous levels of literacy requires further research.

Different MMSE domains are associated to cognitive decline and education

“…Constructional ability, that is, the capability to copy two intersecting pentagons, was positively associated with the education level. This test is recognized as quite difficult for poorly literate or illiterate populations (Raina et al, 2015;Pellicer-Espinosa & D ıaz-Orueta, 2021). Previous studies performed in healthy people consistently found that more educated people had better performances in the MMSE domain Constructional ability (Jones & Gallo, 2002;Laks et al, 2010).…”

“…In the original version, begin with 100 and counting backwards by 7 s, stopping after 5 subtractions. This test is considered difficult for people with low literacy (Rosselli et al, 2006;Pellicer-Espinosa & D ıaz-Orueta, 2021), as a matter of fact in the Portuguese adaptation of the MMSE a simplified version beginning with 30 and counting backwards by 3 s substituted for the original version that many people would not be able to accomplish (Guerreiro et al, 1994). Performance in the MMSE domain Attention and calculation was previously found to be hindered in less educated healthy people (Jones & Gallo, 2002;Laks et al, 2010), and show early loss in disease progression (Ashford et al, 1989), in accordance to the present study.…”

A Retrospective Study on Clinical Assessment of Cognitive Impairment in a Swedish Cohort: Is There Inequality Between Natives and Foreign-Born?

“…We found that foreignborn patients scored lower at MMSE and CDT, but, surprisingly, adjusting for years of education affected only the difference in CDT scores and not in MMSE scores. Education is one of the multiple confounders, together with language, culture and others, that have been shown to affect the MMSE and CDT scores [31][32][33][34][35][36][37][38]. For these reasons, researchers agree that more targeted cognitive tests are needed, and these tests should only be used as a first screening method and not for diagnosis, especially in ethnically diverse populations [32,35,36,38].…”

“…Education is one of the multiple confounders, together with language, culture and others, that have been shown to affect the MMSE and CDT scores [31][32][33][34][35][36][37][38]. For these reasons, researchers agree that more targeted cognitive tests are needed, and these tests should only be used as a first screening method and not for diagnosis, especially in ethnically diverse populations [32,35,36,38]. We chose therefore not to focus on cognitive tests as primary outcomes and instead rely on objective laboratory and imaging biomarkers.…”

Cognitive Outcome After Islet Transplantation

“…The level of education was "high" in a little more than one-quarter of the whole cohort and tended to be higher (about one-third of "high level" education in the transplanted group versus 10% in the control group). The median duration of diabetes at the time of cognitive evaluation was 30 (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) y, with a mean BMI before transplantation of 24.3 ± 2.1 kg/m 2 in the T1D islet-transplanted group (2A + 2B) and a mean BMI at time of cognitive evaluation at 25.8 ± 4 kg/ m 2 in the control group (group 1) and at 22.9 ± 2.5 kg/m 2 in the T1D islet-transplanted group (group 2A + 2B). The cognitive evaluation was performed 3.1 ± 2.6 y after transplantation for the 2A group and 6.9 ± 4 y for the 2B group.…”