MODULATING FACTORS IN THE EARLY STAGES OF COGNITIVE DECLINE: THE ROLE OF COGNITIVE RESERVE

The concept of cognitive reserve (CR) is being increasingly used to explain the observation that there is often a poor correspondence between the presence of pathology at autopsy and the level of cognitive decline in life. Since dementia affects an increasing proportion of the population, imposing a large economic burden on our society, in the absence of disease-modifying treatments it is crucial to detect lifestyle factors that may play a protective role in older individuals, delaying the onset of cognitive impairment. Subjective cognitive impairment (SCI), mild cognitive impairment (MCI) and Alzheimer’s disease (AD) are part of the same spectrum of disease progression. Since memory complaints represent a very common symptom reported by the older community population, early diagnosis of cognitive decline is not always easy, which makes it extremely important to find strategies that help detect individuals who deserve specific exams in a specialist setting. Therefore, we compared a group of individuals with SCI and a sample of patients with MCI, searching for predicting factors of initial cognitive decline. Moreover, we investigated the contribution of CR on cognitive performance in a population of subjects claiming memory difficulties and in a subgroup of patients with MCI undergoing a physical and cognitive training program. Our findings indicated that many variables, including neuroimaging, everyday functional abilities, current activities, CR and behavioral factors are differently expressed in the two populations, with medial temporal lobe atrophy, ADCS scale score and MMSE as the most predictive factors of cognitive impairment. CR resulted a powerful modulating factor of cognitive decline, which is able to support attentive and executive performances in older individuals. The physical and cognitive training program showed a significant positive outcome in patients with MCI, with the main improvements involving memory tests, even though no changes were observed in everyday functional level, nor in the use of mnemonic strategies. Reduced awareness of difficulties was a noteworthy negative predictor of responsiveness to the cognitive stimulation program. Improvement in the memory domain was detected also in subjects with low CR, meaning that neural plasticity makes the enhancement of cognitive performances possible also in late-life, therefore suggesting that cognitive stimulating activities can be useful as non-pharmacological treatments at the early stages of cognitive decline.