The Relationship Between Brain Frailty and Physical Function in Patients With Stroke Undergoing Rehabilitation

 Another useless piece of describing a problem with NO solution provided! I'd fire everyone involved in this crapola!

The Relationship Between Brain Frailty and Physical Function in Patients With Stroke Undergoing Rehabilitation

Motoki Maruyama • Sota Kajiwara • Takuto Oikawa • Masahiro Sasaki Published: March 12, 2025 DOI: 10.7759/cureus.80453  Peer-Reviewed Cite this article as: Maruyama M, Kajiwara S, Oikawa T, et al. (March 12, 2025) The Relationship Between Brain Frailty and Physical Function in Patients With Stroke Undergoing Rehabilitation. Cureus 17(3): e80453. doi:10.7759/cureus.80453

Abstract

Background

Brain frailty has gained attention as a predictor of poor functional outcomes. However, the relationship between brain frailty and physical function among patients with stroke undergoing rehabilitation remains unclear. This study aimed to investigate the relationship between brain frailty and activities of daily living (ADLs) at discharge among patients with stroke admitted to a convalescent rehabilitation ward.

Methods

This single-center retrospective cohort study included patients with stroke admitted to the convalescent rehabilitation ward. Brain frailty (i.e., white matter hyperintensity, old vascular lesions, and brain atrophy) was evaluated using cranial magnetic resonance imaging at stroke onset. The outcome measure was defined as ADLs at discharge, assessed using the motor item of the Functional Independence Measure (FIM-M). Multiple regression and mediation analyses were performed to assess the association between brain frailty scores and FIM-M scores at discharge.

Results

The final analysis included 160 patients (median age: 73.0 years; interquartile range: 64.0-80.0 years; male: n = 90, 56.2%). The multiple regression analysis revealed that severe brain frailty (score of 3) was significantly associated with FIM-M scores at discharge, even after adjusting for covariates (β = −0.18; p = 0.041). Furthermore, mediation analysis revealed that severe brain frailty was associated with FIM-M scores at discharge through the mediation of cognitive function (total effect = −16.20; p < 0.001).

Conclusions

Brain frailty may provide new insights for outcome prediction in stroke rehabilitation, highlighting the importance of incorporating its assessment into routine clinical practice.

Introduction

Frailty has become a critical issue in the field of rehabilitation. This condition is characterized by a multifaceted biopsychosocial syndrome encompassing physical, cognitive, and social vulnerabilities, indicating a pre-disability condition [1]. The prevalence of physical frailty has been reported to be 17.4% among older adults [1], increasing to 27.0% among patients with stroke [2]. Furthermore, frailty is closely associated with other age-related conditions, such as sarcopenia, undernutrition, and low physical activity levels, contributing to a vicious cycle [3]. In patients with stroke, who often have multiple comorbidities associated with aging, frailty has been increasingly recognized as a significant therapeutic target. Previous studies have reported that frailty in patients with stroke is associated with disease severity [4], mortality [5], impaired activities of daily living (ADLs) [6], lower quality of life (QOL) [7], and poorer functional outcomes [8].

Recently, the concept of brain frailty, in addition to physical, cognitive, and social frailty, has gained attention as an emerging condition [9,10]. Brain frailty comprises imaging markers obtained from cranial magnetic resonance imaging (MRI) or computed tomography (CT) scans, including old vascular lesions (e.g., lacunes, old infarcts, and cerebral microbleeds), white matter hyperintensities (WMH), brain atrophy, and enlarged perivascular spaces [9-14]. Patients with stroke often undergo cranial MRI or CT scans early in the course of the disease for diagnostic and differential diagnostic purposes, allowing for the assessment of brain frailty without the need for further evaluation. Previous studies have reported that brain frailty is associated with physical frailty [12], cognitive impairment [9], stroke events [13], and the modified Rankin scale (mRS) score 90 days after stroke onset [9,11]. Furthermore, brain frailty has been reported to be a mediating factor between age and functional outcomes, and it holds potential as a prognostic indicator in aging populations [15]. Based on previous research findings, brain frailty may negatively affect rehabilitation outcomes in patients with stroke who require long-term interventions. Furthermore, as brain frailty adversely affects cognitive function [9], it is necessary to investigate the potential mediating role of cognitive function in the relationship between brain frailty and physical function. However, the specific effects of brain frailty on outcomes in patients with stroke undergoing rehabilitation remain unclear. Brain frailty, which is an easily obtainable measure in routine clinical practice, may serve as a valuable adjunctive marker for predicting rehabilitation outcomes. Furthermore, brain frailty is a common condition among patients with stroke and has the advantage of allowing objective assessment based solely on brain MRI images, without the need for questionnaire-based indices or performance evaluations, as required in conventional frailty assessments. Investigating the relationship between brain frailty, physical function, and cognitive function may provide insights into a comprehensive understanding of how brain frailty affects rehabilitation outcomes.

This study aimed to investigate the association between brain frailty, assessed using MRI at stroke onset, and physical function at discharge in patients with stroke admitted to a convalescent rehabilitation ward. The hypothesis of this study posits that severe brain frailty is associated with ADLs at discharge and that cognitive function partially mediates this association.