Falls in older people: Effects of age and blurring vision on the dynamics of stepping
Falls in older people: Effects of age and blurring vision on the dynamics of stepping
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DOI：
10.1167/iovs.05-0059
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发表时间：
2005-10-01
影响因子：
4.4
通讯作者：
Elliott, DB
中科院分区：
文献类型：
--
作者：
Heasley, K;Buckley, JG;Elliott, DB
目的。随着年龄的增长，跌倒的风险急剧增加，而视力障碍是一个重要的风险因素。因此，评估年龄和视力对与跌倒有关的日常任务表现的影响是非常相关的，例如从一个级别跳到另一个级别。9名年轻人（年龄26 +/- 4岁）和10名老年人（年龄72 +/- 5岁）完成了三个不同高度的加速任务。比较了视力模糊和最佳矫正视力的步进策略。确定质心（CM）、压力中心（CP）动力学（中外侧和前后方向）和足间隙参数，并应用统计回归模型。老年受试者在双支撑时花费的时间比年轻受试者多20% (P = 0.03)，双支撑时前后位CM- cp散度降低（P < 0.001），运动起始和单肢支撑时前后位CM速度（P < 0.001）和中外侧CM速度（P = 0.002）减慢。在两个年龄组中，模糊引起了类似的适应，例如脚趾清除率增加，尽管老年受试者的中外侧（ML） CM-CP差异明显低于年轻受试者（P < 0.001）。研究结果表明，一般来说，年龄较大的受试者使用更谨慎和控制的步伐策略。然而，足趾清除率缺乏显著的年龄差异，这表明该策略主要旨在减少ML不稳定性，而不是增加足趾清除率的安全范围。
PURPOSE. The risk of falling increases dramatically with age, and visual impairment is known to be an important risk factor. Therefore, it is highly pertinent to assess the effects of age and vision on the performance of everyday tasks linked to falling, such as stepping from one level to another.METHODS. Nine young ( age, 26 +/- 4 years) and ten elderly ( age, 72 +/- 5 years) subjects performed a stepping- up task of three different heights. Their stepping strategies with blurred and optimally corrected vision were compared. Center of mass ( CM), center of pressure (CP) dynamics ( in the mediolateral and anteroposterior directions), and foot clearance parameters were determined, and statistical regression modeling was applied.RESULTS. Elderly subjects spent 20% more time ( P = 0.03) than young subjects during double support and they had reduced anteroposterior CM-CP divergence ( P < 0.001) during double support and slower anteroposterior ( P < 0.001) and mediolateral ( P = 0.002) CM velocities during initiation of movement and single limb support. Blur caused similar adaptations, such as increased toe clearance, across both age groups, though mediolateral (ML) CM-CP divergence in elderly subjects was significantly more reduced than in young subjects ( P < 0.001).CONCLUSIONS. Findings indicate, in general, that older subjects used a more cautious and controlled stepping strategy. However, the lack of significant age differences in toe clearance suggests this strategy was mainly aimed at reducing ML instability rather than increasing margins of safety regarding toe clearance.