Department of Clinical and Movement Neuroscience, Institute of Neurology, UCL, London, UK.
Department of Biomedical Sciences, University of Leeds, Leeds, UK.
Neurorehabil Neural Repair. 2024 Apr;38(4):257-267. doi: 10.1177/15459683241230030. Epub 2024 Feb 10.
Increasing perceptual load alters behavioral outcomes in post-stroke fatigue (PSF). While the effect of perceptual load on top-down attentional processing is known, here we investigate if increasing perceptual load modulates bottom-up attentional processing in a fatigue dependent manner.
In this cross-sectional observational study, in 29 first-time stroke survivors with no clinical depression, an auditory oddball task consisting of target, standard, and novel tones was performed in conditions of low and high perceptual load. Electroencephalography was used to measure auditory evoked potentials. Perceived effort was rated using the visual analog scale at regular intervals during the experiment. Fatigue was measured using the fatigue severity scale. The effect of fatigue and perceptual load on behavior (response time, accuracy, and effort rating) and auditory evoked potentials (amplitude and latency) was examined using mixed model ananlysis of variances (ANOVA).
Response time was prolonged with greater perceptual load and fatigue. There was no effect of load or fatigue on accuracy. Greater effort was reported with higher perceptual load both in high and low fatigue. p300a amplitude of auditory evoked potentials (AEP) for novel stimuli was attenuated in high fatigue with increasing load when compared to low fatigue. Latency of p300a was longer in low fatigue with increasing load when compared to high fatigue. There were no effects on p300b components, with smaller N100 in high load conditions.
High fatigue specific modulation of p300a component of AEP with increasing load is indicative of distractor driven alteration in orienting response, suggestive of compromise in bottom-up selective attention in PSF.
增加知觉负荷会改变卒中后疲劳（PSF）的行为结果。虽然已知知觉负荷对自上而下的注意处理有影响，但在这里我们研究了增加知觉负荷是否以疲劳依赖的方式调节自下而上的注意处理。
在这项横断面观察性研究中，在 29 名首次卒中幸存者中，无临床抑郁，在低知觉负荷和高知觉负荷条件下进行了由目标、标准和新颖音调组成的听觉Oddball 任务。使用脑电图测量听觉诱发电位。在实验过程中定期使用视觉模拟量表评估感知努力。使用疲劳严重程度量表测量疲劳。使用混合模型方差分析（ANOVA）检查疲劳和知觉负荷对行为（反应时间、准确性和努力评分）和听觉诱发电位（振幅和潜伏期）的影响。
反应时间随着知觉负荷和疲劳的增加而延长。负载或疲劳对准确性没有影响。在高疲劳和低疲劳条件下，较高的知觉负荷会导致更大的努力。与低疲劳相比，高疲劳时，新颖刺激的听觉诱发电位（AEP）p300a 振幅随负荷增加而减弱。与高疲劳相比，低疲劳时，随着负荷的增加，p300a 的潜伏期更长。p300b 成分没有影响，高负荷条件下 N100 较小。
高疲劳时 AEP 的 p300a 成分随负荷增加而特异性改变，表明在 PSF 中，定向反应受到干扰，表明自下而上的选择性注意力受到损害。
