Affiliations: [a] Departamento de Psicología Experimental, Procesos Cognitivos y Logopedia, Facultad de Psicología, Universidad Complutense de Madrid, España | [b]
Hospital General Universitario Gregorio Marañón, Madrid, España | [c] School of Psychological Sciences and Health, University of Strathclyde, Glasgow, UK
| [d] Neuroprogressive and Dementia Network, NHS Scotland, UK
| [e]
Universidad Autónoma del Caribe, Barranquilla, Colombia
Correspondence:
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Correspondence to: Sara Fernández Guinea, Carretera de Húmera s/n, Campus de Somosaguas, 28223 Pozuelo de Alarcón, Madrid, Spain. Tel.: (+34) 91 394 31 10; Fax: (+34) 91 394 31 89; E-mail: sguinea@psi.ucm.es.
Abstract: Background:Recent research pointed to executive dysfunction as a potential early predictor of the progression of mild cognitive impairment (MCI) to dementia in Alzheimer’s clinical syndrome (ACS). Such cognitive impairments account for functional impairments in instrumental activities of daily living (IADL). Objective:The present study analyzes the contributions of executive functions to predict MCI–dementia progression in ACS. Methods:We assessed 145 participants, 51 cognitively unimpaired and 94 MCI. The latter were divided using the traditional, memory-based MCI classification (single domain amnestic, multidomain amnestic, and non-amnestic). Eight tests assessing executive functions were administered at baseline and at 1-year follow-up, together with cognitive screening tools and IADL measures. MCI patients were reclassified based on the outcomes from a K-mean cluster analysis which identified three groups. A simple lineal regression model was used to examine whether the classification based on executive functioning could more accurately predict progression to dementia a year later. Results:Clusters based on executive function deficits explained a significant proportion of the variance linked to MCI–dementia conversion, even after controlling for the severity of MCI at baseline (F(1, 68) = 116.25, p = 0.000, R2 = 0.63). Classical memory-based MCI classification failed to predict such a conversion (F(1, 68) = 5.09, p = 0.955, R2 = 0.07). Switching, categories generation, and planning were the executive functions that best distinguished between MCI converters and stable. Conclusion:MCI with a dysexecutive phenotype significantly predicts conversion to dementia in ACS a year later. Switching abilities and verbal fluency (categories) must be evaluated in MCI patients to assess risk of future dementia.
