Rizzo John-Ross, Fung James K, Hosseini Maryam, Shafieesabet Azadeh, Ahdoot Edmond, Pasculli Rosa M, Rucker Janet C, Raghavan Preeti, Landy Michael S, Hudson Todd E
Department of Rehabilitation Medicine, New York University Langone Medical Center, New York, NY, United States.
Department of Neurology, New York University Langone Medical Center, New York, NY, United States.
Front Neurol. 2017 Jul 17;8:330. doi: 10.3389/fneur.2017.00330. eCollection 2017.
It is widely accepted that cerebral pathology can impair ocular motor and manual motor control. This is true in indolent and chronic processes, such as neurodegeneration and in acute processes such as stroke or those secondary to neurotrauma. More recently, it has been suggested that disruptions in these control systems are useful markers for prognostication and longitudinal monitoring. The utility of examining the relationship or the coupling between these systems has yet to be determined. We measured eye and hand-movement control in chronic, middle cerebral artery stroke, relative to healthy controls, in saccade-to-reach paradigms to assess eye-hand coordination. Primary saccades were initiated significantly earlier by stroke participants relative to control participants. However, despite these extremely early initial saccades to the target, reaches were nevertheless initiated at approximately the same time as those of control participants. Control participants minimized the time period between primary saccade onset and reach initiation, demonstrating temporal coupling between eye and hand. In about 90% of all trials, control participants produced no secondary, or corrective, saccades, instead maintaining fixation in the terminal position of the primary saccade until the end of the reach. In contrast, participants with stroke increased the time period between primary saccade onset and reach initiation. During this temporal decoupling, multiple saccades were produced in about 50% of the trials with stroke participants making between one and five additional saccades. Reaches made by participants with stroke were both longer in duration and less accurate. In addition to these increases in spatial reach errors, there were significant increases in saccade endpoint errors. Overall, the magnitude of the endpoint errors for reaches and saccades were correlated across participants. These findings suggest that in individuals with otherwise intact visual function, the spatial and temporal relationships between the eye and hand are disrupted poststroke, and may need to be specifically targeted during neurorehabilitation. Eye-hand coupling may be a useful biomarker in individuals with cerebral pathology in the setting of neurovascular, neurotraumatic, and neurodegenerative pathology.
人们普遍认为，脑部病变会损害眼球运动和手动运动控制。在诸如神经退行性变等缓慢和慢性过程中以及在诸如中风或继发于神经创伤的急性过程中都是如此。最近，有人提出，这些控制系统的破坏是预后和纵向监测的有用指标。检验这些系统之间的关系或耦合的效用尚未确定。我们在慢性大脑中动脉卒中患者与健康对照者中，在扫视-伸手范式中测量了眼动和手动运动控制，以评估眼手协调能力。与对照参与者相比，卒中参与者启动初次扫视的时间明显更早。然而，尽管对目标的初次扫视非常早，但伸手动作的启动时间与对照参与者大致相同。对照参与者将初次扫视开始与伸手动作启动之间的时间段减至最短，表明眼和手之间存在时间耦合。在所有试验中，约90% 的对照参与者没有产生二次或校正性扫视，而是在初次扫视的终末位置保持注视，直到伸手动作结束。相比之下，卒中参与者延长了初次扫视开始与伸手动作启动之间的时间段。在这种时间解耦期间，约50% 的试验中产生了多次扫视，卒中参与者额外进行了一到五次扫视。卒中参与者的伸手动作持续时间更长且准确性更低。除了这些空间伸手误差增加外，扫视终点误差也显著增加。总体而言，参与者伸手动作和扫视的终点误差大小呈相关。这些发现表明，在视觉功能原本完好的个体中，眼和手之间的空间和时间关系在卒中后受到破坏，可能需要在神经康复期间专门针对这一点进行训练。在神经血管、神经创伤和神经退行性病变的情况下，眼手耦合可能是脑部病变个体的一种有用生物标志物。
