Functional Connectivity Disruption in Frail Older Adults Without Global Cognitive Deficits.

Isabel Suárez-Méndez,Isabel Suárez-Méndez,Stefan Walter,David López-Sanz,David López-Sanz,Fernando Maestú,Fernando Maestú,Fernando Maestú,Sandra Doval,Sandra Doval,Ernesto Castillo Gallo,Natalia Pasquín,Raquel Bernabé,Myriam Valdés,Stefan Walter,Leocadio Rodríguez-Mañas,Leocadio Rodríguez-Mañas

doi:10.3389/fmed.2020.00322

Abstract

Frailty is a common representation of cumulative age-related decline that may precede disability in older adults. In our study, we used magnetoencephalography (MEG) to explore the existence of abnormalities in the synchronization patterns of frail individuals without global cognitive impairment. Fifty-four older (≥70 years) and cognitively healthy (Mini-Mental State Examination ≥24) adults, 34 robust (not a single positive Fried criterion) and 20 frail (≥3 positive Fried criteria) underwent a resting-state MEG recording and a T1-weighted magnetic resonance imaging scan. Seed-based functional connectivity (FC) analyses were used to explore group differences in the synchronization of fronto-parietal areas relevant to motor function. Additionally, we performed group comparisons of intra-network FC for key resting-state networks such as the sensorimotor, fronto-parietal, default mode, and attentional (dorsal and ventral) networks. Frail participants exhibited reduced FC between posterior regions of the parietal cortex (bilateral supramarginal gyrus, right superior parietal lobe, and right angular gyrus) and widespread clusters spanning mainly fronto-parietal regions. Frail participants also demonstrated reduced intra-network FC within the fronto-parietal, ventral attentional, and posterior default mode networks. All the FC results concerned the upper beta band, a frequency range classically linked to motor function. Overall, our findings reveal the existence of abnormalities in the synchronization patterns of frail individuals within central structures important for accurate motor control. This study suggests that alterations in brain connectivity might contribute to some motor impairments associated with frailty.

Highlights

Population aging arises due to the increase in life expectancy, and the sharp reduction of birth rates
Previous findings suggest that disturbed brain functional connectivity (FC) could contribute to the decline in motor function observed in frail individuals
FC was significantly reduced between posterior regions of the parietal cortex (i.e., supramarginal gyrus (SMG), rSPL, and rAG) and fronto-parietal clusters of brain areas relevant for motor function

Summary

Introduction

Population aging arises due to the increase in life expectancy, and the sharp reduction of birth rates In this context, frailty represents a highly prevalent expression of pathological aging [1]. Several authors have focused on the relationship between brain pathology and individual presentations of frailty, such as gait speed and grip strength [(14, 15), reviewed in [16]]. This indirect evidence provides a relevant yet insufficient frame for the characterization of the neural correlates of the syndrome. The role of the CNS in frailty still represents a wide gap in current geriatric literature [16]

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