Exploring the Neuromechanics of Fall-Risk in Aging

描述(申请人提供)：跌倒是65岁及以上老年人受伤死亡的主要原因，在美国老年人中至少有95%的髋部骨折是由跌倒引起的。随着老年人口(65岁)的增长与美国人口的比例不成比例，与跌倒相关的伤害的治疗和康复费用将给美国经济带来不可持续的负担。尽管NIH为跌倒相关研究分配了大量持续的资金，但老年人跌倒的数量继续增加，这可能是因为这一资金流强调了自愿康复运动的生物力学。年龄较大的自愿恢复运动并不够快，不足以真正防止跌倒的发生。虽然在跌倒的生物力学方面有丰富的知识基础，但在衰老中跌倒风险的神经力学方面存在着相当大的知识缺口。了解到反射系统是唯一能够足够快地做出反应以防止摔倒的系统，我们开发了创新的方法来测试老年人摔倒的“第一道防线”。通过研究衰老对反应的影响，即神经运动系统的第一反应，我们将深入了解导致老年人跌倒风险更大的下降。我们的具体目标是比较：(1)交叉脊柱反射的年龄差异，这是翻正反应的关键组成部分；(2)反射扰动后的姿势恢复；以及(3)反射功能与临床评估的跌倒风险之间的关系。我们预计，老年人的交叉脊柱反射之间的对称性会降低，当他们受到干扰时，姿势恢复不那么直接。这些姿势恢复和交叉脊柱反射方面的缺陷预计与更大的跌倒风险相关。反射缺陷的识别将产生更敏感的跌倒风险筛查程序，从而导致重大的科学突破。此外，大量研究表明，反射是可训练的，因此有可能重新训练反射，作为现有神经肌肉康复方法的补充。 与公共健康相关：CDC报告称，与跌倒相关的伤害是65岁及以上人群死亡的主要原因，从比例上讲，这一年龄段正在成为美国最大的年龄组。尽管跌倒发生的速度对于自愿反应来说往往太快了，但人体的“第一反应”--反射系统--的功能下降是未知的。这些发现与公共健康相关，因为人类的反应可以(重新)训练，为老年人预防跌倒提供了一条新的途径。

DESCRIPTION (provided by applicant): Falls are the leading cause of injury death in people aged 65 and older and cause at least 95% of the hip fractures in older adults in the US. With the elderly population (>65 year-olds) growing out of proportion to the US population, the costs of treatment and rehabilitation of fall-related injuries will place an unsustainable burden on the US economy. Despite a significant and sustained amount of NIH funding being allocated toward fall-related studies, the number of falls suffered by older persons continues to increase, likely due to the emphasis of this funding stream on the biomechanics of voluntary recovery movements. Voluntary recovery movements, with advanced age, are not quick enough to actually prevent a fall from occurring. While the knowledge base is plentiful in the biomechanics of falls, a sizeable knowledge gap exists regarding the neuromechanics of fall-risk in aging. Knowing that the reflex system is the only system that can respond quickly enough to prevent a fall, we have developed innovative methods of testing the "first line of defense" against falls in the elderly. By examining the effects of aging on reflexes, that is, the neuromotor system's first responders, we will gain insight into the declines that lead to greater fall risk in the elderly. Our specific aims are to compare: (1) age differences in crossed-spinal reflexes, a critical component of the righting response; and (2) postural recovery following a reflex perturbation; and (3) the relation between reflex function and clinically assessed fall-risk. We expect that the elderly will exhibit reduced symmetry between their crossed-spinal reflexes with a less direct postural recovery when perturbed. These deficits in postural recovery and crossed-spinal reflexes are expected to correlate with greater fall-risk. The identification of reflex deficits will lead to a significant scientific breakthrough by yielding more sensitive fall-risk screening procedures. Furthermore, the sizeable body of research that has shown that reflexes are trainable holds the potential for reflex re-training as a complement to existing methods of neuromuscular rehabilitation. PUBLIC HEALTH RELEVANCE: The CDC reports that fall-related injuries are the leading cause of death in individuals aged 65 years and older, an age group that is becoming proportionally the largest in America. Even though falls happen at a rate that is often too fast for a voluntary response, the functional decline in the body's "first responders," the reflex system, is unknown. These findings are relevant to public health in that human reflexes can be (re-)trained, providing a new avenue for fall-prevention in the elderly.