Dynamic imaging to guide wearable robotic intervention for enhanced mobility in aging

动态成像指导可穿戴机器人干预以增强衰老过程中的活动能力

• 批准号: 9920637
• 负责人: Jason R Franz
• 金额: $ 32.48万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9920637
• 关键词: Address; Age; Aging; Ankle; Bioenergetics; Biological; Data; Educational Intervention; Elderly; Electromyography; Fascicle; Gait; Gastrocnemius Muscle; Generations; Image; Indirect Calorimetry; Individual; Intervention; Joints; Length; Lower Extremity; Measurement; Measures; Mechanics; Metabolic; Muscle; Muscle Contraction; Muscle Weakness; Musculoskeletal; Neuromechanics; Outcome; Output; Pattern; Performance; Phase; Physiological; Property; Public Health; Published Comment; Quality of life; Self-Help Devices; Series; Soleus Muscle; Speed; Structure; Surface; Tendon structure; Testing; Tissue imaging; Tissues; Triceps Brachii Muscle; Ultrasonography; Walking; Work; achilles tendon; age effect; age related; aging population; ankle joint; body mechanics; cost; electromyographic biofeedback; exoskeleton; functional disability; improved; improved functioning; improved mobility; in vivo; muscle stiffness; novel; preservation; robot exoskeleton; simulation; stem; strength training; treadmill; young adult

ABSTRACT Older adults walk slower and with higher metabolic energy cost than younger adults, changes that reduce independence and quality of life. These functional impairments stem from precipitous reductions in ankle push- off power output that cannot be improved by conventional strength training. Growing evidence reveals that muscle activation patterns tuned to underlying triceps surae (TS) muscle-tendon structural properties facilitate an effective burst of ankle power output during push-off. This study addresses two key questions: (1) Do age- related changes in series-elastic Achilles tendon (AT) structural properties (i.e., stiffness, kT) disrupt the tuned neuromechanical function of the TS with cascading metabolic penalties? and (2) Can donning elastic exoskeletons in parallel with biological TS muscle-tendons alter structural stiffness and improve the neuromechanics and energy cost of walking in older adults? Specific Aim 1 will quantify how aging effects activation-dependent tuning of triceps surae muscle-Achilles tendon interaction dynamics. Using controlled loads on a dynomometer and physiological loads during treadmill walking, we will couple advanced, dual-probe cine ultrasound imaging of TS muscle fascicles and localized AT tissue with novel electromyographic biofeedback to assess individual contributions of muscle versus tendon (kM and kT) to overall TS muscle-tendon stiffness (kMT) over a full landscape of muscle activation. Combined with metabolic measurements, we will test the hypotheses that (1A) older adults have a more complaint AT (i.e., lower kT) than young adults and thus, (1Bi) in isolated muscle contractions at prescribed TS muscle activations, older adults operate at shorter TS muscle fascicle lengths, and (1Bii) during walking at matched speeds, in an attempt to maintain overall kMT, older adults increase TS muscle stiffness (i.e., higher kM) by shifting to higher activations with shorter fascicle lengths than young adults -- with energetic implications at the (1) individual TS muscle (force per unit activation) and (b) whole- body (walking economy) levels. Specific Aim 2 will determine how elastic ankle exoskeletons alter the neuromechanics and energetics of walking in older adults – from whole-body to individual muscles. Using a novel ankle exoskeleton emulator we will apply a range of exo-tendons (kEXO) in parallel with the TS muscle- tendon (kMT) while older adults walk at a fixed treadmill speed. We will test the hypotheses that (2A) older adults using elastic ankle exoskeletons will demonstrate reduced TS muscle activation and longer TS muscle fascicle operating lengths, and (2B) for older adults, the kEXO that most closely normalizes TS muscle-tendon stiffness (kMT) to that of their size-matched, young counterparts will yield the most youthful walking performance, evidenced by: (i) largest increase in ankle push-off power output and (ii) largest reduction in metabolic energy cost. Ultimately, this work will establish a framework for using ultrasound imaging to guide optimal prescription of assistive devices that can effectively modify the structure of the ankle triceps surae muscle-tendons to improve locomotor function in aging – an outcome that will have significant positive impact on quality of life for millions.

抽象的 老年人步行慢，代谢能量成本较慢，而年轻人则可以减少变化 独立性和生活质量。这些功能障碍源于踝关节踝关节的精确降低 传统的力量训练无法改善功率输出。越来越多的证据表明 肌肉激活模式调整为基础三头肌（TS）肌肉刺激结构特性有助于 推断过程中有效的踝关节功率输出。这项研究解决了两个关键问题：（1）年龄 - 串联弹性跟腱（AT）结构特性（即刚度，KT）的相关变化破坏了调谐的 TS的神经力学功能具有级联代谢处罚？ （2）可以穿弹性 与生物TS肌肉弯曲并联的外骨骼改变结构僵硬并改善 在老年人中行走的神经力学和能源成本？特定目标1将量化衰老的影响 三头肌的激活依赖性调节肌肌肌肌腱相互作用动力学。使用受控 在跑步机行走期间，在士兵计和物理负荷上的负载，我们将融入高级，双探针 TS肌肉束的Cine超声成像，并在组织中与新型肌电反馈局部 评估肌肉与肌腱（km和kt）对总体TS肌肉弯曲僵硬（KMT）的个人贡献 在肌肉激活的完整景观上。结合代谢测量，我们将测试假设 （1a）老年人的投诉比（即KT较低）的投诉比年轻人，因此（1BI）在孤立的 处方肌肉激活的肌肉收缩，在较短的TS肌肉筋膜上运作的老年人 长度和（1BII）以匹配的速度行走，以维持整体KMT，老年人增加 TS肌肉刚度（即更高km）通过比年轻的筋膜长度转向更高的激活 成年人 - 在（1）个体TS肌肉（每单位激活力）和（b）全部具有能量意义 身体（步行经济）水平。特定的目标2将决定弹性踝部外骨骼如何改变 从全身到个体肌肉，在老年人中行走的神经力学和能量学。使用 新型脚踝外骨骼模拟器我们将与TS肌肉并行应用一系列外阵螺丝（Kexo） 肌腱（KMT）老年人以固定的跑步机速度行走。我们将测试（2A）老年人的假设 使用弹性脚踝外骨骼将表明TS肌肉激活减少，而TS肌肉筋膜更长 运营长度，（2B）的老年人，最紧密地归一化TS肌肉刺激性的Kexo （KMT）与他们匹配的年轻同行相匹配的人将产生最年轻的步行表演， 证明：（i）踝关节推动力输出的最大增加和（ii）代谢能量的最大减少 成本。最终，这项工作将建立一个使用超声成像指导最佳处方的框架 辅助设备可以有效地修改脚踝三头肌的结构以改进 运动功能在衰老中 - 这种结果将对数百万的生活质量产生重大积极影响。