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The sensory role of muscle for the control of balance

肌肉对平衡控制的感觉作用

基本信息

批准号：
BB/L02103X/1
负责人：
Raymond Reynolds
金额：
$ 41.56万
依托单位：
University of Birmingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2014
资助国家：
英国
起止时间：
2014 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FL02103X%2F1
关键词：
sensory role muscle control balance

项目摘要

Falls are a major problem for older adults, with 30% of people aged over 65 experiencing 1 or more falls per year, rising to 50% in the over 85's. The reasons for falling are multi-factorial, and include problems with both sensation and movement. One of the most important types of sensory input for balance comes from the calf muscles in the lower leg, termed 'proprioception'. There is evidence to suggest that loss of proprioception in older adults may be a key cause of postural instability. However, muscles must produce movement as well as act as sensory organs. Ongoing muscle contraction may therefore affect the ability of muscle to act as a sensor. This, in turn, is affected by individual variations in ankle stiffness, and overall muscle strength. It is well established that these factors change with age, and this may therefore degrade the ability of the muscle to detect body movement. We will test this hypothesis by measuring proprioceptive control of balance in older adults (aged 65-85). Initially, we will examine balance in younger volunteers (aged 18-40) to establish baseline performance. In particular, we will determine how natural variations in ankle stiffness and muscle strength affect the quality of sensory information emanating from the calf muscles during quiet standing. To assess the quality of proprioceptive information in each volunteer, we will use ultrasound to measure calf muscle movement to see how well muscle length tracks body sway when standing. This will be correlated with postural stability. We will then determine how mechanical factors such as ankle stiffness and ankle strength affect this relationship. Furthermore, we will test the influence of these factors upon the ability of subjects to detect very small rotations at the ankle joint. Using an innovative 'virtual' standing paradigm, we will then artificially manipulate strength and ankle stiffness to mimic the ageing phenotype in the young. Once we have established baseline performance in the young, we will study older adults to determine how the well-established musculoskeletal changes affect proprioceptive control of sway. Using the same virtual standing paradigm, we will test the effect of artificially improving function. The strength of our approach is that we can compare proprioception between groups (young vs old) as well as manipulate the above factors within subjects. This combined approach will give us a comprehensive picture of how proprioceptive information is used to control balance, both in the young and aged state. By revealing the mechanisms by which sensory information is used for balance, we will better understand how these mechanisms degrade with age leading to postural instability. This will be of benefit both in being able to better identify those at risk of falling, and being able to tailor specific therapies to improve balance function.

福尔斯是老年人的主要问题，65岁以上的人中有30%每年经历一次或多次福尔斯，85岁以上的人中这一比例上升到50%。跌倒的原因是多方面的，包括感觉和运动方面的问题。平衡的最重要的感觉输入类型之一来自小腿的小腿肌肉，称为“本体感觉”。有证据表明，老年人的本体感觉丧失可能是姿势不稳定的一个关键原因。然而，肌肉必须产生运动以及作为感觉器官。因此，持续的肌肉收缩可能会影响肌肉作为传感器的能力。这反过来又受到踝关节僵硬度和整体肌肉力量的个体差异的影响。众所周知，这些因素随着年龄的增长而变化，因此这可能会降低肌肉检测身体运动的能力。我们将通过测量老年人（65-85岁）的本体感受平衡控制来验证这一假设。最初，我们将检查年轻志愿者（18-40岁）的平衡，以建立基线性能。特别是，我们将确定踝关节僵硬度和肌肉力量的自然变化如何影响安静站立时小腿肌肉发出的感觉信息的质量。为了评估每个志愿者的本体感受信息的质量，我们将使用超声波测量小腿肌肉运动，看看肌肉长度如何跟踪站立时的身体摇摆。这将与姿势稳定性相关。然后，我们将确定机械因素，如踝关节刚度和踝关节强度如何影响这种关系。此外，我们将测试这些因素对受试者检测踝关节微小旋转的能力的影响。使用一种创新的“虚拟”站立模式，我们将人工操纵力量和脚踝刚度，以模仿年轻人的衰老表型。一旦我们在年轻人中建立了基线性能，我们将研究老年人，以确定如何建立良好的肌肉骨骼变化影响本体感觉控制摇摆。使用相同的虚拟站立范例，我们将测试人工改善功能的效果。我们的方法的优势在于，我们可以比较各组（年轻人与老年人）之间的本体感受，并在受试者中操纵上述因素。这种结合的方法将为我们全面了解本体感受信息如何用于控制年轻和老年状态的平衡。通过揭示感官信息用于平衡的机制，我们将更好地理解这些机制如何随着年龄的增长而退化，从而导致姿势不稳定。这将有利于更好地识别那些有跌倒风险的人，并能够定制特定的治疗方法来改善平衡功能。