Screening for Alzheimer's Disease Among Illiterate Elderly: Accuracy Analysis for Multiple Instruments

Abstract

One of the challenges in screening for dementia in developing countries is related to performance differences due to educational and cultural factors. This study evaluated the accuracy of single screening tests as well as combined protocols including the Mini-Mental State Examination (MMSE), Verbal Fluency animal category (VF), Clock Drawing test (CDT), and Pfeffer Functional Activities Questionnaire (PFAQ) to discriminate illiterate elderly with and without Alzheimer's disease (AD) in a clinical sample. Cross-sectional study with 66 illiterate outpatients diagnosed with mild and moderate AD and 40 illiterate normal controls. Diagnosis of AD was based on NINCDS-ADRDA. All patients were submitted to a diagnostic protocol including a clinical interview based on the CAMDEX sections. ROC curves area analyses were carried out to compare sensitivity and specificity for the cognitive tests to differentiate the two groups (each test separately and in two by two combinations). Scores for all cognitive (MMSE, CDT, VF) and functional assessments (PFAQ) were significantly different between the two groups (p < 0.001). The best screening instruments for this sample of illiterate elderly were the MMSE and the PFAQ. The cut-off scores for the MMSE, VF, CDT, and PFAQ were 17.5, 7.5, 2.5, and 11.5, respectively. The most sensitive combination came from the MMSE and PFAQ (94.1%), and the best specificity was observed with the combination of the MMSE and CDT (89%). Illiterate patients can be successfully screened for AD using well-known screening instruments, especially in combined protocols.

Miniexame do Estado Mental: evidências de validade baseadas na estrutura interna

“…Muitas pesquisas têm destacado que a escolaridade influencia o desempenho no MEEM (Bertolucci et al, 1994;Brucki, Mansur, Carthery-Goulart, & Nitrini, 2011) e, consequentemente, deve ser considerada ao se estabelecerem pontos de corte. Alerta-se que não somente a quantidade de anos estudados é importante mas também a qualidade do ensino recebido e sua influência sobre o desenvolvimento cognitivo, especialmente na velhice (Aprahamian, Martinelli, Cecato, & Yassuda, 2011) e em países em desenvolvimento, como o Brasil, onde a educação formal é muito heterogênea (Farfel et al, 2013 O segundo componente extraído na ACPOrientação -reuniu os mesmos dez itens agrupados no estudo de Folstein et al (1975). Embora sejam funções importantes a serem avaliadas no contexto da cognição, autores, como Carnero-Pardo (2013), argumentam que valerse de 10 itens para avaliar a orientação em um instrumento com um total de 30 itens pode ser exagero.…”

Development, validity, and reliability of the General Activities of Daily Living Scale: a multidimensional measure of activities of daily living for older people

“…The Pfeffer Functional Activities Questionnaire seems to be one of the most commonly used tools for functional assessment aiming at the investigation of IADL performance. [7][8][9][10] One study using the Pfeffer scale 7 found an additive effect between functional scores and the Mini Mental State Examination (MMSE) for the diagnosis of AD. The Disability Assessment for Dementia was also adapted for Brazil 11 and seems to be useful for the characterization of functionality in frontotemporal dementia and AD, assessing both BADLs and IADLs as well as leisure activities, although these two groups do not show differences in functional performance.…”

Reply

“…. and a sample derived from a public primary care unit in Rio de Janeiro" (Lourenço et al, 2008;Aprahamian et al, 2011), further reinforcing the point of view that the matter is not related to the instrument but rather to the specific characteristics of their sample.…”

“…Bottom line: sample and classification bias have determined the results and conclusions reported by Aprahamian et al (2011), with which we vehemently disagree, i.e. that "the CAMCOG retains high accuracy when used in samples of elderly with limited education".…”

“…The sample in the Aprahamian et al (2011) study was made up of 321 community-dwelling outpatients from a private geriatric institution. Although lacking full data on the sample's socioeconomic status, patients assisted at private clinics in Brazil are people with better economic conditions, since they have the means either to afford such services or to contribute to private health insurance policies.…”