P2-203: Amnestic mild cognitive impairment or very mild Alzheimer’s disease? Results from the ReGAl project

Abstract

The Clinical Dementia Rating (CDR) is a useful scale used to classify subjects along a continuum from normal aging through various stages of dementia. A CDR of 0.5 actually describes a broader population that includes subjects with Mild Cognitive Impairment (MCI) and very mild Alzheimer's disease (AD). To investigate the substantial differences between these two condition in clinical settings. The analysis included 242 subjects with CDR 0.5 (132 amnestic MCI –aMCI– according to Petersen's criteria, and 110 AD), participating to a large multicentric clinical–based study (the ReGAl project). Each subject underwent an extensive neurologic, medical, and neuropsychological evaluation. The neurophychological test battery included measures of global mental status, memory, language, attention, and constructional abilities. Functional status was assessed with the Basic Activities of Daily Living (BADL) and the Instrumental Activities of Daily Living (IADL). Disability was defined as dependence in at least one item. All statistical analyses were performed using the Statistical Package for Social Science (SPSS) version 12.0 for Windows. There were no differences in age (aMCI mean age 76.1±5.8, AD mean age 76.7±6.6) and gender distribution (aMCI F% 56.8, AD F% 58.2). Very mild AD subjects had a lower educational level compared to aMCI (5.9±3.7 and 7.1±4.2 years, respectively, p=0.02). While aMCI and AD subjects presented similar memory impairment, AD subjects showed worst performances in all other neuropsychological tests (p<0.001). Regarding functional status there was no difference in disability in ADL, whereas AD subjects presented more impairment in IADL, compared to aMCI (OR 3.0, 95% CI 1.7–5.5, in logistic regression model adjusted for age, gender, years of education and comorbidity). Among IADL item, AD subjects had more dysfunction in shopping (OR 2.4, 95% CI 1.4–4.3), cooking (OR 2.5, 95% CI 1.4–4.6), and, especially, in taking drugs (OR 4.5, 95% CI 2.4–8.3). In this large Italian multicentric clinical–based study, with a CDR rating score of 0.5, the diagnosis of AD is related mainly to the worst global cognitive impairment, whereas in the functional status, the difference between AD and aMCI is limited to few (shopping, cooking and taking drugs) instrumental activities of daily living.