[Exploratory analysis of the influence of cognitive reserve on the benefits of cognitive stimulation therapy in patients with sporadic late-onset Alzheimer's disease].

INTRODUCTION: The main objective of cognitive stimulation therapies is to promote the plasticity and learning ability that the individual is still in possession of in old age and to delay the clinical manifestations of neurodegenerative processes such as Alzheimer-type dementia. There are variables that can mediate the benefits of the intervention, such as the cognitive reserve. AIM: To determine whether there is an interaction between the level of reserve and cognitive stimulation, and if it influences the cognitive performance of subjects with Alzheimer-type dementia. PATIENTS AND METHODS: Twenty subjects (age: 66-89) with Alzheimer-type dementia who attend a day centre participated in the study. A pretest-posttest controlled design was used. The pilot group took part in the intervention for six months. Patients were classified into two levels of cognitive reserve (high and low) and then a broad neuropsychological battery was applied to perform a comprehensive analysis of cognition. Pre- and post-intervention differences were analysed through a two-factor ANOVA, one with repeated measures (pre- and post-intervention scores) and another with independent measures (level of cognitive reserve). RESULTS: Interaction was found in the scores on the picture arrangement subtests (WAIS-III), failure to maintain the category and the percentage of errors in the Wisconsin Card Sorting Test. CONCLUSIONS: The positive effect of the interaction on the executive function has been observed, specifically in the capacities for planning and sequencing, perceptual organisation, response inhibition, logical reasoning and mental flexibility.