Harwood Amanda E, Greenwood Pamela M, Shaw Tyler H
ARCH Laboratory, Department of Psychology, George Mason University Fairfax, VA, USA.
Front Aging Neurosci. 2017 Feb 8;9:21. doi: 10.3389/fnagi.2017.00021. eCollection 2017.
Given that older adults are remaining longer in the workforce, their ability to perform demanding cognitive tasks such as vigilance assignments needs to be thoroughly examined, especially since many vigilance assignments affect public safety (e.g., aviation, medicine and long distance driving). Previous research exploring the relation between aging and vigilance is conflicted, with some studies finding decreased vigilance performance in older adults but others finding no effect of age. We sought a better understanding of effects of age on vigilance by assessing neurophysiological change over the course of a vigil in young (aged 18-24) and healthy older (aged 66-77) adults. To measure temporal changes in cerebral blood flow, participants underwent functional transcranial doppler (fTCD) recording during a 1 h vigilance task. Based on research showing a compensatory effect of increased left hemisphere activation during vigilance in young adults and the "hemispheric asymmetry reduction in older adults" (HAROLD) model, we predicted that during vigilance our older adults would show greater left hemisphere activation but perform at a similar level compared to young adults. While cerebral blood flow velocity (CBFV) declined over time in both groups, only young adults showed the typical right-lateralized CBFV pattern. Older adults showed greater left hemisphere activation consistent with the HAROLD model. However, the increased left hemisphere activation did not appear to be compensatory as the older adults performed at a significantly lower level compared to young adults over the vigil. Findings are discussed in terms of the HAROLD model of healthy aging and the resource theory of vigilance.
鉴于老年人在职劳动力中停留的时间更长，他们执行诸如警戒任务等要求较高的认知任务的能力需要得到全面研究，特别是因为许多警戒任务会影响公共安全（例如，航空、医学和长途驾驶）。先前探索衰老与警戒之间关系的研究存在矛盾，一些研究发现老年人的警戒表现下降，而另一些研究则未发现年龄的影响。我们通过评估年轻（18 - 24岁）和健康老年（66 - 77岁）成年人在警戒过程中的神经生理变化，来更好地理解年龄对警戒的影响。为了测量脑血流量的时间变化，参与者在1小时的警戒任务期间接受了功能性经颅多普勒（fTCD）记录。基于研究表明年轻成年人在警戒期间左半球激活增加具有补偿作用以及“老年人半球不对称性减少”（HAROLD）模型，我们预测在警戒期间，我们的老年成年人将表现出更大的左半球激活，但与年轻成年人相比表现水平相似。虽然两组的脑血流速度（CBFV）都随时间下降，但只有年轻成年人表现出典型的右侧化CBFV模式。老年成年人表现出与HAROLD模型一致的更大的左半球激活。然而，左半球激活的增加似乎并没有起到补偿作用，因为在整个警戒过程中，老年成年人的表现明显低于年轻成年人。研究结果将根据健康衰老的HAROLD模型和警戒的资源理论进行讨论。
