Haaxma R, van Boxtel A, Brouwer W H, Goeken L N, Denier van der Gon J J, Colebatch J G, Martin A, Brooks D J, Noth J, Marsden C D
Department of Neurology, University Hospital, Groningen, The Netherlands.
Mov Disord. 1995 Nov;10(6):761-77. doi: 10.1002/mds.870100610.
This study describes the long-term deficits of a patient who, after a toxic encephalopathy, sustained extensive bilateral damage to both segments of the globus pallidus (GP) and the right substantia nigra (SN). There were no signs of lesions of the pyramidal tracts or of other motor structures. The most obvious deficits were an abnormal gait with an exaggerated knee extension and a tendency to fall slowly, especially when pushed backward. In contrast, Romberg's test on an unstable platform was normal, as were long-latency leg reflexes induced by perturbations. Inadequate anticipatory and compensatory postural responses, in particular across the hip and knee joints, and slow movements seemed responsible for the falls. Muscle tone was normal but reflex studies showed signs of abnormal facilitation and inhibition at various levels of the neuraxis. We conclude that the GP and SN lesions caused defective input to premotor cortical and brain stem target zones. Dysfunctioning of these zones leads to improper control of the descending ventromedial motor system responsible for locomotion, postural control, and reflex status. The deficits in upper extremity motor performance included delayed and slow movements, inaccurate amplitudes of ballistic responses, a lack of predictive control, and deficits in bimanual coordination. Sensory feedback, proprioceptive more than visual, played a powerful compensating role in rapid aiming movements. Regional blood flow (studied using 15(O)2) was reduced in multiple frontal cortical regions, among which are the hand areas of the supplementary and premotor cortex. We hypothesize that this reflected impaired functioning of these areas, caused by defective bilateral output from GP and SN, and resulting in the motor deficits of the arm and hand.
本研究描述了一名患者的长期缺陷，该患者在发生中毒性脑病后，双侧苍白球（GP）的两个节段和右侧黑质（SN）均遭受广泛损伤。没有锥体束或其他运动结构受损的迹象。最明显的缺陷是步态异常，膝关节伸展过度，且有缓慢跌倒的倾向，尤其是在被向后推时。相比之下，在不稳定平台上进行的罗姆伯格试验正常，由扰动诱发的长潜伏期腿部反射也正常。预期性和补偿性姿势反应不足，尤其是在髋关节和膝关节处，以及动作缓慢似乎是导致跌倒的原因。肌张力正常，但反射研究显示在神经轴的不同水平存在异常易化和抑制的迹象。我们得出结论，GP和SN损伤导致运动前皮质和脑干靶区的输入缺陷。这些区域功能失调导致负责运动、姿势控制和反射状态的下行腹内侧运动系统控制不当。上肢运动表现的缺陷包括动作延迟和缓慢、弹道反应幅度不准确、缺乏预测性控制以及双手协调缺陷。感觉反馈，尤其是本体感觉而非视觉反馈，在快速瞄准动作中发挥了强大的补偿作用。多个额叶皮质区域的局部血流（使用15（O）2研究）减少，其中包括辅助运动皮质和运动前皮质的手部区域。我们推测，这反映了这些区域的功能受损，是由GP和SN的双侧输出缺陷引起的，并导致了手臂和手部的运动缺陷。
