Wagner Andrew R, Chaudhari Ajit Mw, Merfeld Daniel M
School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, Ohio, USA.
Otolaryngology-Head and Neck Surgery, Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
Int J Phys Med Rehabil. 2021;9(Suppl 8). Epub 2021 Oct 11.
Falls are the leading causes of accidental injury in older adults and directly contribute to more than 600,000 deaths each year worldwide. Although the issue of falls is complex, balance dysfunction is one the principal contributors to the heightened incidence of falls in older adults. A nationally representative survey of older adults in the United States showed that an inability to stand on a foam pad with the eyes closed was associated with more than a six-fold increase in the odds of reporting "difficulty with falls." As stability in the "eyes closed, on foam" condition is reliant upon intact vestibular cues, these data implicate age-related vestibular loss as a potential contributor to falls, yet, the specific causal mechanism explaining the link between age-related vestibular loss and imbalance/falls was not known. Here we review recent data showing that, vestibular perceptual thresholds, an assay of vestibular sensory noise, were found to, (1) account for nearly half of subclinical balance impairment in healthy older adults and (2) correlate with postural sway in healthy young adults. Based upon the identified links between balance dysfunction and vestibular noise in healthy adults, we posit the following causal chain: (a) increased "noise" in vestibular feedback - yielding a reduced signal-to-noise ratio in vestibular feedback-increases sway, (b) excessive sway leads to imbalance, and (c) imbalance contributes to falls. Identifying the "cause" of age-related balance dysfunction will inform the development of interventions tailored to prevent falls, and fall-related injuries, in the growing population of older adults.
跌倒是老年人意外伤害的主要原因，在全球范围内每年直接导致超过60万人死亡。尽管跌倒问题很复杂，但平衡功能障碍是老年人跌倒发生率升高的主要原因之一。一项针对美国老年人的全国代表性调查显示，无法闭眼站在泡沫垫上与报告“跌倒困难”的几率增加六倍以上有关。由于“闭眼站在泡沫垫上”状态下的稳定性依赖于完整的前庭线索，这些数据表明年龄相关的前庭功能丧失是跌倒的一个潜在因素，然而，解释年龄相关前庭功能丧失与失衡/跌倒之间联系的具体因果机制尚不清楚。在此，我们回顾了近期的数据，这些数据表明，前庭感知阈值（一种前庭感觉噪声的检测方法）被发现：（1）在健康老年人中，几乎占亚临床平衡障碍的一半；（2）与健康年轻人的姿势摇摆相关。基于在健康成年人中确定的平衡功能障碍与前庭噪声之间的联系，我们提出以下因果链：（a）前庭反馈中“噪声”增加——导致前庭反馈中的信噪比降低——增加摇摆；（b）过度摇摆导致失衡；（c）失衡导致跌倒。确定年龄相关平衡功能障碍的“原因”将为制定针对性干预措施提供依据，以预防日益增多的老年人群中的跌倒及跌倒相关损伤。
