Higher-Level Executive Functions in Mild Cognitive Impairment: A Systematic Review

Abstract

Mild Cognitive Impairment (MCI) is a clinical syndrome characterized by a moderate decline in one or more cognitive functions with a preserved autonomy in daily life activities [1]. MCI exhibits cognitive, behavioral, psychological symptoms [2]. The executive functions (EFs) are a set of key functions for everyday life and physical and mental health; and allow adapting the behavior to external changes [3-5]. Higher-level executive functions develop from basic EFs (inhibition, working memory, attentional control, and cognitive flexibility). They are planning, reasoning, problem-
 solving, and fluid intelligence (Gf) [3].
 This systematic review investigates the relationship between higher-level executive functions and healthy and pathological aging, assuming the role of executive functions deficits as a predictor of cognitive decline. The systematic review was conducted according to the PRISMA Statement [6-7]. A total of 73 studies were identified.
 The results indicate that 65.8% of the studies confirm significant EFs alterations in MCI (100% problem solving, 71.4% fluid intelligence, 56.8% planning, 50% reasoning). These results seem to highlight a strong prevalence of higher-level executive functions deficits in MCI elderly than in healthy elderly.

The role of cognitive flexibility on higher level executive functions in mild cognitive impairment and healthy older adults

“…It is further hypothesized that global cognitive functioning (MMSE score) will play a mediating role. Moreover, due to the lack of studies examining (a) the components of cognitive flexibility, (b) the relationship between cognitive flexibility (and its components) and higher-level executive functioning in different forms of aging; given the central role of cognitive flexibility in higher-level executive functioning [20] and the role of switching and set-shifting in defining cognitive flexibility [22,43], the second hypothesis is that II) the components of cognitive flexibility can predict higher-level executive functions in older adults with Mild Cognitive Impairment, with the mediating role of global cognitive functioning, as measured by the MMSE score. (32 of 45) females.…”

“…Therefore, we excluded participants with medical conditions that could influence cognitive functions, in order to control for any potential comorbidity that could interfere with the study of mild cognitive impairment. An independent sample of 300 healthy participants (see [43]) was employed to obtain the factor weights with the purpose of developing a weighted composite score of switching and set-shifting.…”

“…To assess the second hypothesis, the results of a previous confirmatory factor analysis (CFA) [43] To assess whether cognitive flexibility can predict higher executive functioning in aging with Mild Cognitive Impairment, linear regressions were performed on the total sample, the healthy older adults, and the older adults with MCI. In the linear regressions, planning and fluid intelligence were used as dependent variables.…”