Ongoing Oscillatory Electrophysiological Alterations in Frail Older Adults: A MEG Study.

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

doi:10.3389/fnagi.2021.609043

Abstract

Objective: The role of the central nervous system in the pathophysiology of frailty is controversial. We used magnetoencephalography (MEG) to search for abnormalities in the ongoing oscillatory neural activity of frail individuals without global cognitive impairment.Methods: Fifty four older (≥70 years) and cognitively healthy (Mini-Mental State Examination ≥24) participants were classified as robust (0 criterion, n = 34) or frail (≥ 3 criteria, n = 20) following Fried's phenotype. Memory, language, attention, and executive function were assessed through well-validated neuropsychological tests. Every participant underwent a resting-state MEG and a T1-weighted magnetic resonance imaging scan. We performed MEG power spectral analyses to compare the electrophysiological profiles of frail and robust individuals. We used an ensemble learner to investigate the ability of MEG spectral power to discriminate frail from robust participants.Results: We identified increased relative power in the frail group in the mu (p < 0.05) and sensorimotor (p < 0.05) frequencies across right sensorimotor, posterior parietal, and frontal regions. The ensemble learner discriminated frail from robust participants [area under the curve = 0.73 (95% CI = 0.49–0.98)]. Frail individuals performed significantly worse in the Trail Making Test, Digit Span Test (forward), Rey-Osterrieth Complex Figure, and Semantic Fluency Test.Interpretation: Frail individuals without global cognitive impairment showed ongoing oscillatory alterations within brain regions associated with aspects of motor control, jointly to failures in executive function. Our results suggest that some physical manifestations of frailty might partly arise from failures in central structures relevant to sensorimotor and executive processing.

Highlights

Frailty is one of the major expressions of cumulative age-related decline that may precede disability in older adults, affecting 10– 17% of the aged population (Collard et al, 2012)
Several authors propose that the central nervous system (CNS) is implicated in the pathophysiology of frailty, causing the cognitive decline that some patients experience alongside the physical manifestations of the syndrome (Ávila-Funes et al, 2009)
Frail individuals exhibited increased relative power across sensorimotor, posterior parietal, and frontal areas predominantly localized in the right hemisphere (RH)

Summary

Introduction

Frailty is one of the major expressions of cumulative age-related decline that may precede disability in older adults, affecting 10– 17% of the aged population (Collard et al, 2012). The complex pathophysiology of frailty has led to several controversies concerning the domains that integrate the syndrome, and the systems and organs involved in its development. In this regard, the participation of the central nervous system (CNS), and brain structure and function, is one of the queries fueling debate. Several authors propose that the CNS is implicated in the pathophysiology of frailty, causing the cognitive decline that some patients experience alongside the physical manifestations of the syndrome (Ávila-Funes et al, 2009). Even if current clinical instruments for diagnosing frailty focus on testing physical items, they might reveal expressions of brain dysfunctionality beyond cognition (Rodríguez-Mañas and Sinclair, 2014)

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Results

Conclusion