Cognitive Predictors of Cortical Thickness in Healthy Aging

Cognitive Reserve Moderates the Efficiency of Prefrontal Cortex Activation Patterns of Gait in Older Adults

BACKGROUND

Cognitive Reserve (CR) protects against cognitive decline, but whether CR influences the efficiency of cortical control of gait has not been reported. The current study addressed this important gap in the literature. Specifically, we determined the role of CR in moderating the efficiency of functional Near-Infrared-Spectroscopy (fNIRS)-derived HbO2 in the prefrontal cortex (PFC) assessed during active walking. We hypothesized that higher CR would be associated with more efficient brain activation patterns.

METHODS

Participants were 55 (mean age=74.84; %female=49.1) older adults who underwent the combined walking/fNIRS protocol and had MRI data. We used an established dual-task walking paradigm that consisted of three task conditions: Single-Task-Walk (STW), Single-Task-Alpha (STA, cognitive task) and Dual-Task-Walk (DTW). Using the residuals approach, CR was derived from a word-reading test score by removing variance accounted for by socio-demographic variables, tests of current cognitive functions and a measure of structural brain integrity.

RESULTS

CR moderated the change in fNIRS-derived HbO2 in the PFC across tasks. Higher CR was associated with smaller increases in fNIRS-derived HbO2 from the single tasks to dual task walking (CR x DTW compared to STW: estimate = .183; p < .001; CR x DTW compared to STA: estimate =.257; p < .001). The moderation effect of CR remained significant when adjusting for multiple covariates and concurrent moderation effects of measures of gait performance, current cognitive functions and structural integrity of the brain.

CONCLUSION

The current study provided first evidence that higher CR was associated with better neural efficiency of walking in older adults.

Large-Scale Morphological Network Efficiency of Human Brain: Cognitive Intelligence and Emotional Intelligence

Network efficiency characterizes how information flows within a network, and it has been used to study the neural basis of cognitive intelligence in adolescence, young adults, and elderly adults, in terms of the white matter in the human brain and functional connectivity networks. However, there were few studies investigating whether the human brain at different ages exhibited different underpins of cognitive and emotional intelligence (EI) from young adults to the middle-aged group, especially in terms of the morphological similarity networks in the human brain. In this study, we used 65 datasets (aging 18–64), including sMRI and behavioral measurements, to study the associations of network efficiency with cognitive intelligence and EI in young adults and the middle-aged group. We proposed a new method of defining the human brain morphological networks using the morphological distribution similarity (including cortical volume, surface area, and thickness). Our results showed inverted age × network efficiency interactions in the relationship of surface-area network efficiency with cognitive intelligence and EI: a negative age × global efficiency (nodal efficiency) interaction in cognitive intelligence, while a positive age × global efficiency (nodal efficiency) interaction in EI. In summary, this study not only proposed a new method of morphological similarity network but also emphasized the developmental effects on the brain mechanisms of intelligence from young adult to middle-aged groups and may promote mental health study on the middle-aged group in the future.

The "SuperAgers" construct in clinical practice: neuropsychological assessment of illiterate and educated elderly

INTRODUCTION

The demographic transition is a global event intensified during the last decades that represents population aging. Thus, the studies directed to the elderly 80 years of age or more with preserved cognitive functions (named SuperAgers) emerges as a possible path to full comprehension of the health of those aging with acceptable levels of functionality and independency.

OBJECTIVE

To evaluate the cognitive performance of the elderly over 80 years old, associating the results to their educational level.

METHOD

We evaluated 144 healthy elders with 80 years or more through the following cognitive tests Mini-Mental State Examination (MMSE), Cambridge Cognitive Examination (CAMCOG), Clock Drawing Test (CDT), and Verbal Fluency Test (VF) and compared the tests' scores with their educational level segmented in years of formal education, being the groups ILLITR (<1 year of schooling), 1TO4 (from 1 to 4 years of schooling), and 5MORE (>5 years of schooling).

RESULTS

There was positive influence of educational level on the cognitive tests' score, which indicates higher cognitive reserve of the elderly with higher educational levels.

CONCLUSION

The functionality and independence of the so-called SuperAgers is determined by the cognitive reserve acquired throughout life, mainly developed by the years of formal education.