PhD Dissertation Pre-defense of Federico Gallo

Institute for Cognitive Neuroscience (Center for Cognition and Decision Making) is pleased to annouce the Ph.D. Pre-defense of Federico Gallo which will take place on 15th December, 2021 at 18.00. The event will be held online.

Thesis title: "Effects of individual experience on prevention and compensation of age related cognitive decline: neural and behavioral data"
Academic advisor: Prof. Yuri Shtyrov, PhD, Institute for Cognitive Neuroscience

Abstract:

Average life expectancy has been steadily increasing worldwide over the last decades (Kontis et al., 2017). Alongside the advantages of an extended  life span, this phenomenon brings about some undesirable consequences, including an ever-growing incidence of dementia and consequent increases in the expenditures of public governments’ welfare systems (Wimo et al., 2017). At the neural level, aging has been linked to structural as well as functional disruptions (Walhovd et al., 2011), resulting in cognitive impairments (Lindenberger, 2014). Nonetheless, considerable interindividual variability has emerged in the degree of cognitive decline resulting from age-related brain damage (Cosentino & Stern, 2019). Based on existing evidence, several mechanisms of preservation and compensation of age-related cognitive impairment have been proposed. The main theoretical framework centers around the concept of  cognitive reserve , defined as the level of resilience of an individual’s cognitive processes to age-related brain deterioration (Stern et al., 2020). Whereas much is yet to be understood regarding the nature of cognitive reserve, what is known is that it develops gradually during the lifespan and it is supported by a number of experiential factors (Stern, 2009), including maximal educational attainment, occupational complexity, and the extent of the individual’s social network (Dekhtyar et al., 2019). One factor that has been linked to the build-up of cognitive reserve is bilingualism (Gallo et al., 2020): by means of a constant additional cognitive effort required to control dual-language use (Kroll et al., 2015), bilinguals strengthen their neural substrate – both at the structural and the functional levels (Abutalebi & Green, 2016; Bialystok, 2017). This results in a protective effect that counteracts age-related cognitive decline and is mediated by the cognitive reserve mechanism (Del Maschio et al., 2018).

In my PhD research, I examined the role of individual life experiences, bilingualism in particular, in promoting the development of cognitive reserve during the whole lifespan. Moreover, with the aim of tackling the long-standing issue of cognitive reserve measurability, I devised a novel method (by refining recent approaches) for measuring cognitive reserve directly and tested its validity by comparing it with traditional approaches to cognitive reserve measurement, for the first time in the literature. This method, based on combining neuroimaging and behavioral data, quantifies reserve as the discrepancy between observed and expected levels of cognitive impairment (i.e., the residual), given the level of observed neural deterioration. The newly-developed cognitive reserve measure may provide a two-fold contribution: i) since it represents an individual, continuous, direct and brain-related measure, it may contribute to advancing the theoretical framework of cognitive reserve – currently undergoing considerable debate (see e.g., Stern et al., 2020) – by allowing new levels of comparability and manipulability that will aid future studies; ii) it may inform the clinical practice by allowing clinicians to draw an individual profile of each patient’s cognitive decline trajectory. This would enable the design of truly personalized care plans and thus the achievement of better results in the prevention and rehabilitation of age-related cognitive diseases. Thus, the results of the research presented in this dissertation may potentially make concrete beneficial contributions to society: by individuating factors, such as bilingualism, that naturally postpone and mitigate the cognitive consequences of brain aging and by delineating the mechanisms underlying this process, this type of research may eventually equip governments with a tool to improve the quality of life of older adults, while at the same time easing the burden on healthcare systems and public funds.