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视觉-前庭觉输入一致性影响老年人站姿稳定性及其脑电图脑网络特征

杨毅¹, 王国正², 华安珂¹, 郝增明³, 黄聪¹, 刘军², 王健^1,*

¹浙江大学运动科学与健康工程研究所，杭州 310028；²浙江大学生物医学工程学院，杭州 310028；³中山大学附属第一医院，广州 510062

摘要

衰老是影响站姿稳定性控制和导致跌倒频发的重要因素，但其作用机制尚不完全清楚。本研究旨在通过对比老年人和青年人在视觉-前庭觉输入一致和冲突条件下站姿稳定性及站姿脑电图(electroencephalogram, EEG)脑网络节点连接强度的差异，探讨衰老弱化站姿稳定性控制的EEG脑网络节点连接强度效应。无神经肌肉系统疾病的老年人(n = 18)和青年人(n = 18)志愿者参与本研究。用虚拟现实技术(virtual reality, VR)操作视觉旋转刺激(顺时针和逆时针)，用水平旋转平台操作前庭觉旋转刺激(顺时针)，根据感觉输入在水平面的方向差异性将视觉和前庭觉输入一致性分为视觉-前庭觉输入一致和视觉-前庭觉输入冲突。依据站姿足底压力中心(center of pressure, COP)移动轨迹检测站姿稳定性，用EEG信号采集和有向网络分析技术观察EEG脑网络连接节点连接强度。结果显示，老年人在视觉-前庭觉输入冲突条件下COP前后方向摆动速度、总轨迹长以及前后和左右方向样本熵等站姿稳定性表现方面明显不及青年人，视皮质节点连接强度明显大于青年人，颞上皮质节点连接强度明显低于青年人。以上结果提示，老年人在站姿平衡控制中对视觉依赖性高；老年人无法很好应对视觉-前庭觉输入不一致引起的感觉冲突，导致站姿稳定性差。本研究结果对今后老年人平衡功能评估和跌倒预防训练具有重要的实践意义。

关键词： 视觉-前庭觉输入冲突; 站姿稳定性; 脑电图脑网络; 节点连接强度

The effect of visual-vestibular sensory input consistency on standing stability and electroencephalogram brain network characteristics in the elderly

YANG Yi¹, WANG Guo-Zheng², HUA An-Ke¹, HAO Zeng-Ming³, HUANG Cong¹, LIU Jun², WANG Jian^1,*

¹Kenisiology and Health Engineering Institute, Zhejiang University, Hangzhou 310028, China；²School of Biomedical Engineering, Zhejiang University, Hangzhou 310028, China；³The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510062, China

Abstract

Aging is a crucial factor influencing postural stability control and contributing to frequent falls, yet its underlying mechanisms remain incompletely understood. This study aims to explore the effects of aging on postural stability control by comparing differences in postural stability and node strength of electroencephalogram (EEG) brain network between elderly and young people under the conditions of congruent and incongruent visual-vestibular sensory inputs. Eighteen elderly volunteers without neuromuscular disorders and eighteen young individuals participated in the present study. Virtual reality (VR) technology was employed to manipulate visual rotation stimuli (clockwise and counterclockwise), and a horizontal rotating platform was used for vestibular rotation stimuli (clockwise). Based on the directional disparity of sensory input in the horizontal plane, visual-vestibular input consistency was categorized as congruent and incongruent. Postural stability was assessed by the center of pressure (COP) trajectory, and EEG signals were collected and analyzed using directed network analysis to observe EEG brain network node connectivity strength. The results revealed that, under conditions of incongruent visual-vestibular sensory inputs, the elderly exhibited significantly inferior postural stability performance in terms of COP anterior-posterior (Y-axial) sway speed, total path length, anterior-posterior and medial-lateral sample entropy, compared to the young adults. Moreover, the node connectivity strength of visual cortex in the elderly was notably higher, while node connectivity strength of superior temporal cortex was significantly lower than that in the young adults. These findings suggest that the elderly have a heightened reliance on visual information in postural control and an impaired ability to cope with sensory conflicts arising from incongruent visual-vestibular sensory inputs, leading to compromised postural stability. The outcomes of this study hold significant implications for future assessments of balance function in the elder and fall prevention trainings.

Key words: visual-vestibular input conflict; postural stability; EEG brain network; node connection strength

收稿日期：　　录用日期：

通讯作者：王健　　E-mail: pclabeeg@zju.edu.cn

DOI: 10.13294/j.aps.2023.0089

引用本文：

杨毅, 王国正, 华安珂, 郝增明, 黄聪, 刘军, 王健. 视觉-前庭觉输入一致性影响老年人站姿稳定性及其脑电图脑网络特征[J]. 生理学报 2023; 75 (6): 918-926.

YANG Yi, WANG Guo-Zheng, HUA An-Ke, HAO Zeng-Ming, HUANG Cong, LIU Jun, WANG Jian. The effect of visual-vestibular sensory input consistency on standing stability and electroencephalogram brain network characteristics in the elderly. Acta Physiol Sin 2023; 75 (6): 918-926 (in Chinese with English abstract).