Muscle age acceleration shapes resting-state brain connectivity: an EEG study on older adults

Aging is a multifaceted process where physiological metrics, such as brain age and muscle age (MA), provide deeper insights than chronological age alone. These nonlinear trajectories are heavily influenced by exogenous factors like lifestyle and nutrition. In older populations, muscle age acceleration (MAA) critically impacts functional autonomy and cognitive health, necessitating research into its link with brain network organization to refine assessments and, based on these, integrated motor and cognitive rehabilitation strategies. In this study, eyes-closed resting-state electroencephalography (EEG) was recorded from 101 healthy, neurologically intact older adults. MA and MAA were quantified using a regression model incorporating the functional assessments recommended by the European Working Group on Sarcopenia in Older People (EWGSOP-2) consensus (anthropometrics, muscle strength, and motor functional tests). Participants were stratified into three groups based on their MAA: decelerated MA, normal MA, and accelerated MA. Brain connectivity was assessed through magnitude-squared coherence (MSCoh) and node strength analyses. The results demonstrated that decelerated MA subjects exhibit significantly lower MSCoh compared to the normal and accelerated groups in the Alpha 1, Alpha 2, and Beta 1 bands. Furthermore, node strength analysis revealed that the decelerated MA group possessed lower values in the right frontal area across Alpha 1, Beta 1, and Beta 2 bands. Conversely, the normal MA group exhibited lower values in the right temporal region compared to the accelerated MA group. These findings may suggest that divergent muscle aging trajectories significantly modulate brain network topography. This brain-body interconnection highlights the potential for personalized interventions designed to redirect muscle aging trajectories, ultimately enhancing global functioning and quality of life of older people.