Stepping over obstacles: Dividing attention impairs performance of old more than young adults
Stepping over obstacles: Dividing attention impairs performance of old more than young adults
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DOI：
10.1093/gerona/51a.3.m116
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发表时间：
1996-05-01
影响因子：
5.1
通讯作者：
Guire, KE
中科院分区：
文献类型：
--
作者：
Chen, HC;Schultz, AB;Guire, KE
背景。被障碍物绊倒是老年人跌倒的常见原因。早期一项关于避免踩到突然出现的障碍物能力的研究发现，尽管健康的老年人成功率低于年轻人，但这种差异的幅度并不大。本研究探讨在此类任务中分散注意力是否会对健康的年轻人和老年人产生不同的影响。
方法。观察了16名年轻健康成年人和16名老年健康成年人（平均年龄分别为24岁和72岁）在以舒适的步速行走时避免踩到突然投射在其行走路径上的一条光带的成功率。这个虚拟障碍物被放置在预测的下一步落脚点位置，在落脚点之前提供350或450毫秒的可用反应时间。在大多数试验中，除了要求受试者尽量不踩到障碍物外，还要求他们在走道尽头附近的红灯亮起时尽可能快地口头做出反应。这些分散注意力的反应时间测试有两种类型：同步的，即只有与障碍物出现同步间隔亮起的红灯；非同步的，即除了红灯外还有绿灯或黄灯亮起，且亮灯间隔与障碍物出现不同步。
结果。当同步和非同步反应时间测试与避障任务同时进行时，年轻人和老年人的平均避障成功率均显著下降。在可用反应时间为350毫秒的情况下，年轻人在同步反应和非同步反应的注意力分散测试中，平均成功率较无注意力分散时的值分别下降了14.7%和19.9%。老年人相应的平均下降率分别为32.0%和35.7%。这种分散注意力影响的年龄差异是显著的。
结论。当年轻人和老年人的注意力被分散时，他们在跨越障碍物时接触到障碍物的风险均显著增加，但分散注意力对老年人避障能力的损害明显大于对年轻人的损害。当注意力被转移到其他地方时，对环境中存在的物理危险做出反应的能力下降，这可能是老年人跌倒率高的部分原因。
Background. Tripping over an obstacle is a common cause of falls in the elderly. An earlier study of abilities to avoid stepping on suddenly appearing obstacles found that, although healthy old adults had a lower rate-of-success than young adults, the magnitude of that difference was not large. The present study inquired whether dividing attention during such a task would differentially affect young and old healthy adults.Methods. Rates-of-success were observed in 16 young and 16 old healthy adults (mean ages 24 and 72 years in avoiding stepping on a band of light that was suddenly projected across their gait path while they walked at their comfortable gait speed. This virtual obstacle was placed at predicted nest-footfall locations to give 350 or 450 msec available response times before footfall. During most of the trials the subjects were asked, in addition to trying not to step on the obstacle, simultaneously to respond vocally as quickly as possible when red lights near the end of the walkway turned on. These attention-dividing reaction time tests were of two types: synchronized, when only red lights lit at intervals synchronized with the appearance of the obstacle, and unsynchronized, when green or yellow lights lit in addition to the red lights, with lighting intervals not synchronized with the appearance of the obstacle.Results. When synchronized and unsynchronized reaction time tests were conducted concurrently with the obstacle avoidance tasks, mean rates-of-success in avoidance decreased significantly in both young and old adults. With available response times of 350msec, mean success rates decreased from their no-division values in the young adults by 14.7% for synchronized reaction and by 19.9% for unsynchronized reaction, attention-dividing tests. Corresponding mean decreases for the old adults were 32.0 and 35.7%. This age difference in the effects of dividing attention was significant.Conclusion. Both young and old adults had a significantly increased risk of obstacle contact while negotiating obstacles when their attention was divided, but dividing attention degraded obstacle (sic) of the old significantly more than it did in the young. Diminished abilities to respond to physical hazards present in the environment when attention is directed elsewhere may partially account for high rates of falls among the elderly.