Carleton University, Institute of Cognitive Science, Ottawa, Canada; The Ottawa Hospital Research Institute, Ottawa, Canada.
The Ottawa Hospital Research Institute, Ottawa, Canada.
Mult Scler Relat Disord. 2021 Sep;54:103130. doi: 10.1016/j.msard.2021.103130. Epub 2021 Jul 10.
Cognitive fatigability (CF) can be defined as an inability to maintain an optimal level of performance throughout a sustained cognitive task. It remains unclear, however, whether there is a specific moment during a cognitive task, such as the Paced Auditory Serial Addition Test (PASAT), when performance begins to break down. Thus, the present study aimed to evaluate how performance declines over time on the PASAT in people with multiple sclerosis (PwMS) compared to healthy controls.
178 PwMS and 186 control participants were administered the 3" and 2" PASAT as part of a larger battery of neuropsychological tests. To examine how CF differed between the groups, repeated measures ANOVAs were used to evaluate the cumulative error rates made by each group throughout the task. In addition, how the error rate developed across the task on each trial was examined to evaluate in more detail the difference between groups with respect to how performance declined from the beginning to the end of the task. Lastly, exploratory two-way independent sample ANOVAs examined whether there was an influence of stimulus complexity (single vs. double-digit answers) on task performance.
Compared to healthy controls, PwMS produced a greater number of errors overall on the PASAT and demonstrated more vulnerability to CF than healthy controls, as reflected by a greater number of errors made towards the end of the task. This difference was more noticeable on the 3" PASAT, given the difficulty both groups experienced on the 2" form. On the 3" PASAT, by Trial 37, PwMS had made significantly more cumulative errors than controls, however the rate of error generation was largely consistent and linear from the beginning to the end. Some of the group differences observed may be partially attributable to stimulus complexity influencing task performance.
The 3" PASAT is more sensitive to group differences in CF and error generation than the 2" PASAT. With respect to CF, the greater vulnerability observed in the MS group is not due to a breakdown in performance or an increase in the rate of error generation at any specific point during the task; rather there is a linear decline in performance from the start. These results suggest that PwMS struggle to maintain optimal performance during sustained cognitive effort from the very beginning and demonstrate a steeper, but steady, rate of decline over time.
认知疲劳（CF）可以定义为在持续的认知任务中无法保持最佳表现水平的能力。然而，目前尚不清楚在认知任务（例如 Paced Auditory Serial Addition Test（PASAT））中是否存在特定时刻，在此时刻，表现开始下降。因此，本研究旨在评估多发性硬化症（PwMS）患者与健康对照者在 PASAT 上的表现随时间的下降情况。
178 名 PwMS 和 186 名对照参与者接受了 3" 和 2" PASAT 的测试，作为更大的神经心理学测试组合的一部分。为了研究 CF 在两组之间的差异，我们使用重复测量方差分析来评估每组在整个任务过程中的累积错误率。此外，还检查了在每个试验中任务的错误率是如何发展的，以便更详细地评估两组在任务开始到结束时表现下降的差异。最后，探索性的双因素独立样本方差分析检查了刺激复杂性（单位数和两位数答案）是否对任务表现有影响。
与健康对照组相比，PwMS 在 PASAT 上总体上产生了更多的错误，并且比健康对照组更容易受到 CF 的影响，这反映在任务结束时犯的错误更多。在 3" PASAT 上，这种差异更为明显，因为两组都在 2" 形式上遇到了困难。在 3" PASAT 上，到第 37 次试验时，PwMS 累积错误明显多于对照组，但是从开始到结束，错误生成的速度大致保持一致和线性。观察到的一些组间差异可能部分归因于刺激复杂性对任务表现的影响。
3" PASAT 比 2" PASAT 更能敏感地反映 CF 和错误生成方面的组间差异。就 CF 而言，在 MS 组中观察到的更大的脆弱性并不是由于在任务的任何特定点表现崩溃或错误生成率增加所致；相反，从一开始表现就呈线性下降。这些结果表明，PwMS 在持续的认知努力中从一开始就难以保持最佳表现，并且随着时间的推移表现呈稳步下降趋势。
