Department of Kinesiology, The Pennsylvania State University, 32 Rec Building, University Park, PA, 16802, USA.
Department of Rehabilitation Medicine and Neurology, New York University Langone Medical Center, New York, NY, USA.
Exp Brain Res. 2023 Feb;241(2):547-558. doi: 10.1007/s00221-023-06550-8. Epub 2023 Jan 10.
In complex visuomotor tasks, such as cooking, people make many saccades to continuously search for items before and during reaching movements. These tasks require cognitive resources, such as short-term memory and task-switching. Cognitive load may impact limb motor performance by increasing demands on mental processes, but mechanisms remain unclear. The Trail-Making Tests, in which participants sequentially search for and make reaching movements to 25 targets, consist of a simple numeric variant (Trails-A) and a cognitively challenging variant that requires alphanumeric switching (Trails-B). We have previously shown that stroke survivors and age-matched controls make many more saccades in Trails-B, and those increases in saccades are associated with decreases in speed and smoothness of reaching movements. However, it remains unclear how patients with neurological injuries, e.g., stroke, manage progressive increases in cognitive load during visuomotor tasks, such as the Trail-Making Tests. As Trails-B trial progresses, switching between numbers and letters leads to progressive increases in cognitive load. Here, we show that stroke survivors with damage to frontoparietal areas and age-matched controls made more saccades and had longer fixations as they progressed through the 25 alphanumeric targets in Trails-B. Furthermore, when stroke survivors made saccades during reaching movements in Trails-B, their movement speed slowed down significantly. Thus, damage to frontoparietal areas serving cognitive motor functions may cause interference between oculomotor, visual, and limb motor functions, which could lead to significant disruptions in activities of daily living. These findings augment our understanding of the mechanisms that underpin cognitive-motor interference during complex visuomotor tasks.
在复杂的视动任务中，例如烹饪，人们在进行伸手动作之前和期间会进行多次扫视，以不断搜索物品。这些任务需要认知资源，例如短期记忆和任务转换。认知负荷可能会通过增加对心理过程的需求来影响肢体运动表现，但机制尚不清楚。连线测试由简单数字变体（Trails-A）和需要进行字母数字切换的认知挑战变体（Trails-B）组成，参与者在其中按顺序搜索并进行 25 个目标的伸手动作。我们之前已经表明，中风幸存者和年龄匹配的对照组在 Trails-B 中进行了更多的扫视，并且这些扫视的增加与伸手运动速度和流畅度的下降有关。然而，目前尚不清楚患有神经损伤的患者（例如中风）如何在视觉运动任务（例如连线测试）中管理认知负荷的逐渐增加。随着 Trails-B 试验的进展，在数字和字母之间切换会导致认知负荷逐渐增加。在这里，我们表明，前额顶叶区域受损的中风幸存者和年龄匹配的对照组在进行 Trails-B 的 25 个字母数字目标时，会进行更多的扫视，并且注视时间更长。此外，当中风幸存者在 Trails-B 中的伸手运动中进行扫视时，他们的运动速度明显减慢。因此，负责认知运动功能的额顶区域的损伤可能会导致眼球运动、视觉和肢体运动功能之间的干扰，这可能会导致日常生活活动的严重中断。这些发现增加了我们对复杂视动任务中认知运动干扰的潜在机制的理解。
