Kitano K, Hirayama K, Tokumaru Y, Furumoto H, Komatsuzaki A
Rinsho Shinkeigaku. 1989 May;29(5):593-8.
Selective paralysis of downward gaze, first described by André-Thomas et al. in 1933, is rare to be observed and not many cases have been so far reported in the literature. Two additional cases of selective impairment of downward gaze have been reported. X-ray CT scan revealed the infarcted areas in the midbrain tegmentum and bilateral paramedian thalami in both cases. Angiographic studies have revealed that the arteries occluded might be the paramedian thalamic arteries and their mesencephalic branches. According to the reported clinico-pathological studies and, in addition, to the results of the physiological studies in animal models, the responsible site of lesion for downward gaze failure is thought to be the rostral interstitial nucleus of MLF (riMLF). In one of the cases (28 year-old female, case 1), while vertical slow pursuit eye movements and upward saccade were normal in speed and range, maximum speed of eyes in voluntary downward saccade was markedly reduced and the eyes moved down slowly as if moving in oil (slow eye movement, viscosité). Passively extending the patient's head while she tried to fix her eyes on an unmoving object (doll's eye phenomenon), the speed of her eyes in downward saccade did not increase. In the other case (45 year-old male, case 2), the patient's voluntary and reflex downward eye movements were completely impaired and he could not look down nor follow the object below extending the horizontal meridian level. With regard to the unique features of abnormal eye movements observed in our cases, the possibility of coexistence of saccadic and slow pursuit eye movement systems in the vertical plane was discussed.
选择性下视麻痹最早由安德烈 - 托马斯等人于1933年描述，临床罕见，迄今文献报道的病例不多。本文报告另外2例选择性下视功能障碍。2例患者的X线CT扫描均显示中脑被盖和双侧丘脑旁正中梗死灶。血管造影研究显示，闭塞的动脉可能是丘脑旁正中动脉及其中脑分支。根据已报道的临床病理研究以及动物模型的生理学研究结果，下视功能障碍的责任病灶部位被认为是内侧纵束间质核头端（riMLF）。其中1例（28岁女性，病例1），垂直慢跟踪眼动和向上扫视的速度和幅度正常，但主动下视扫视时眼球的最大速度明显降低，眼球向下移动缓慢，犹如在油中移动（慢眼动，viscosité）。当患者试图注视一个静止物体时被动伸展其头部（玩偶眼现象），其下视扫视时眼球速度并未增加。另一例（45岁男性，病例2），患者的主动和反射性下视眼动完全受损，无法向下看，也不能跟踪低于水平子午线平面的物体。关于我们病例中观察到的异常眼动的独特特征，讨论了垂直平面内扫视和慢跟踪眼动系统共存的可能性。
