Functional Connectivity Disruption in Frail Older Adults Without Global Cognitive Deficits

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.

Frailty Is Associated With Cognitive Decline Independent of Cerebral Small Vessel Disease and Brain Atrophy

“…To the best of our knowledge no prior studies have evaluated the independent effect of frailty on cognitive decline over and above cSVD and brain atrophy. Our finding suggest frailty may represent other factors such as the effect of inflammation ( 29 ), vascular dysregulation ( 30 ), impaired white matter microstructure ( 7 ), or functional connectivity ( 31 , 32 ) that we were unable to measure. The FI may therefore be a good overall marker of multiple risk factors (eg, high blood pressure and diabetes) for dementia or of other factors such as slow gait speed that share common underlying neural networks ( 33 ).…”

Frailty and functional brain connectivity (FBC) in older adults with mild cognitive impairment (MCI): baseline results from the SYNERGIC Trial

“…Our findings both support and refute previous research. Only two studies have examined the relationship between FBC and frailty status [ 27 , 28 ]. Both used the Cardiovascular Health Study–Frailty Phenotype [ 29 ], only included cognitively normal older adults, and restricted their analysis to motor regions.…”

“…FBC can be measured using functional magnetic resonance imaging and is considered a sensitive biomarker in those at risk of progression to dementia as changes precede structural atrophy and occur years before clinical manifestation [ 26 ]. We know of only two studies that have examined FBC and frailty status, using magnetoencephalography [ 27 ] and functional magnetic resonance imaging [ 28 ]. Both studies classified their cognitively healthy sample using the Cardiovascular Health Study–Frailty Phenotype, which focuses largely on physical frailty domains [ 29 ] and restricted their investigation of FBC to motor areas [ 27 , 28 ].…”

“…We know of only two studies that have examined FBC and frailty status, using magnetoencephalography [ 27 ] and functional magnetic resonance imaging [ 28 ]. Both studies classified their cognitively healthy sample using the Cardiovascular Health Study–Frailty Phenotype, which focuses largely on physical frailty domains [ 29 ] and restricted their investigation of FBC to motor areas [ 27 , 28 ]. We found no studies that examined the relationship between frailty and FBC in individuals with cognitive impairment or how a more multidimensional measure of frailty status, such as the frailty index (FI) [ 30 ], is associated with FBC in motor areas and beyond.…”

Joint cmICA: auto-linking of structural and functional connectivity

“…In prior studies, the most widely used approaches to match SC and FC involves evaluating the correlation/distance between (vectorized) SC and FC matrices (Honey et al, 2009; Liégeois, Santos, Matta, Van De Ville, & Sayed, 2020; Suárez-Méndez et al, 2020), where both matrices’ nodes are pre-defined and macroscopic.…”