Neuropsychological Contribution to Predict Conversion to Dementia in Patients with Mild Cognitive Impairment Due to Alzheimer’s Disease

Article type: Research Article

Authors: Silva, Dina^{a; b; *} | Cardoso, Sandra^b | Guerreiro, Manuela^b | Maroco, João^c | Mendes, Tiago^{b; d} | Alves, Luísa^e | Nogueira, Joana^{f; g} | Baldeiras, Inês^{h; i; j} | Santana, Isabel^{f; h; i; j} | de Mendonça, Alexandre^b

Affiliations: [a] Cognitive Neuroscience Research Group, Department of Psychology and Educational Sciences and Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal | [b] Faculty of Medicine, University of Lisbon, Lisbon, Portugal | [c] Instituto Superior de Psicologia Aplicada, Lisbon, Portugal | [d] Psychiatry and Mental Health Department, Santa Maria Hospital, Lisbon, Portugal | [e] Chronic Diseases Research Centre, NOVA Medical School, NOVA University of Lisbon, Portugal | [f] Department of Neurology, Dementia Clinic, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal | [g] Faculty of Psychology and Educational Sciences, University of Coimbra, Coimbra, Portugal | [h] Department of Neurology, Laboratory of Neurochemistry, Centro Hospitalar e Universitário de Coimbra | [i] Faculty of Medicine, University of Coimbra, Coimbra, Portugal | [j] Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal

Correspondence: [*] Correspondence to: Dina Silva, Instituto de Farmacologia e Neurociências, Edifício Egas Moniz, Faculdade de Medicina de Lisboa, Avenida Prof. Egas Moniz, 1649-028 Lisboa, Portugal. E-mail: dinasilva@fm.ul.pt.

Abstract: Background:Diagnosis of Alzheimer’s disease (AD) confirmed by biomarkers allows the patient to make important life decisions. However, doubt about the fleetness of symptoms progression and future cognitive decline remains. Neuropsychological measures were extensively studied in prediction of time to conversion to dementia for mild cognitive impairment (MCI) patients in the absence of biomarker information. Similar neuropsychological measures might also be useful to predict the progression to dementia in patients with MCI due to AD. Objective:To study the contribution of neuropsychological measures to predict time to conversion to dementia in patients with MCI due to AD. Methods:Patients with MCI due to AD were enrolled from a clinical cohort and the effect of neuropsychological performance on time to conversion to dementia was analyzed. Results:At baseline, converters scored lower than non-converters at measures of verbal initiative, non-verbal reasoning, and episodic memory. The test of non-verbal reasoning was the only statistically significant predictor in a multivariate Cox regression model. A decrease of one standard deviation was associated with 29% of increase in the risk of conversion to dementia. Approximately 50% of patients with more than one standard deviation below the mean in the z score of that test had converted to dementia after 3 years of follow-up. Conclusion:In MCI due to AD, lower performance in a test of non-verbal reasoning was associated with time to conversion to dementia. This test, that reveals little decline in the earlier phases of AD, appears to convey important information concerning conversion to dementia.

Keywords: Alzheimer’s disease (AD), amyloid-β, cognitive impairment, dementia, mild cognitive impairment due to AD, neuropsychological assessment, prodromal AD, Raven Coloured Progressive Matrices

DOI: 10.3233/JAD-191133

Journal: Journal of Alzheimer's Disease, vol. 74, no. 3, pp. 785-796, 2020