Graduate School of Health Sciences, Seirei Christopher University, Hamamatsu-City, Shizuoka 433-8558, Japan.
BMC Neurosci. 2013 Jan 18;14:10. doi: 10.1186/1471-2202-14-10.
The purpose of this study was to examine task-related changes in prefrontal cortex (PFC) activity during a dual-task in both healthy young and older adults and compare patterns of activation between the age groups. We also sought to determine whether brain activation during a dual-task relates to executive/attentional function and how measured factors associated with both of these functions vary between older and younger adults.
Thirty-five healthy volunteers (20 young and 15 elderly) participated in this study. Near-infrared spectroscopy (NIRS) was employed to measure PFC activation during a single-task (performing calculations or stepping) and dual-task (performing both single-tasks at once). Cognitive function was assessed in the older patients with the Trail-making test part B (TMT-B). Major outcomes were task performance, brain activation during task (oxygenated haemoglobin: Oxy-Hb) measured by NIRS, and TMT-B score. Mixed ANOVAs were used to compare task factors and age groups in task performance. Mixed ANOVAs also compared task factors, age group and time factors in task-induced changes in measured Oxy-Hb. Among the older participants, correlations between the TMT-B score and Oxy-Hb values measured in each single-task and in the dual-task were examined using a Pearson correlation coefficient.Oxy-Hb values were significantly increased in both the calculation task and the dual-task within patients in both age groups. However, the Oxy-Hb values associated with there were higher in the older group during the post-task period for the dual-task. Also, there were significant negative correlations between both task-performance accuracy and Oxy-Hb values during the dual-task and participant TMT-B scores.
Older adults demonstrated age-specific PFC activation in response to dual-task challenge. There was also a significant negative correlation between PFC activation during dual-task and executive/attentional function. These findings suggest that the high cognitive load induced by dual-task activity generates increased PFC activity in older adults. However, this relationship appeared to be strongest in participants with better baseline attention and executive functions.
本研究旨在观察健康的年轻和老年成年人在双重任务期间前额叶皮层（PFC）活动的与任务相关的变化，并比较两个年龄组之间的激活模式。我们还试图确定双重任务期间的大脑激活与执行/注意力功能之间的关系，以及这两个功能的测量因素在老年人和年轻人之间的差异。
35 名健康志愿者（20 名年轻志愿者和 15 名老年志愿者）参与了这项研究。近红外光谱（NIRS）用于测量单一任务（进行计算或踏步）和双重任务（同时进行两项任务）期间的 PFC 激活。使用 Trail-making 测试部分 B（TMT-B）对老年患者进行认知功能评估。主要结果是任务表现、NIRS 测量的任务期间大脑激活（含氧血红蛋白：Oxy-Hb）和 TMT-B 评分。混合方差分析用于比较任务因素和年龄组在任务表现方面的差异。混合方差分析还比较了任务因素、年龄组和时间因素对测量的 Oxy-Hb 在任务诱导变化中的差异。在老年参与者中，使用 Pearson 相关系数分析了 TMT-B 评分与每个单一任务和双重任务中的 Oxy-Hb 值之间的相关性。在两个年龄组的患者中，计算任务和双重任务的 Oxy-Hb 值均显著增加。然而，在双重任务后的后任务期间，老年组的 Oxy-Hb 值更高。此外，在双重任务期间的任务表现准确性和 Oxy-Hb 值与参与者的 TMT-B 评分之间存在显著的负相关。
老年成年人在应对双重任务挑战时表现出特定于年龄的 PFC 激活。在双重任务期间，PFC 激活与执行/注意力功能之间也存在显著的负相关。这些发现表明，双重任务活动引起的高认知负荷会导致老年成年人的 PFC 活动增加。然而，这种关系在基线注意力和执行功能较好的参与者中似乎最强。
