Heide W, Fahle M, Koenig E, Dichgans J, Schroth G
Department of Neurology, University of Tübingen, Federal Republic of Germany.
J Neurol. 1990 Nov;237(7):432-40. doi: 10.1007/BF00314736.
We present two cases with acute onset of vertical gaze palsy, mainly consisting of impaired downgaze and apraxia of downward head movements, together with neuropsychological deficits (hypersomnia, impaired attention and disorders of memory and affective control). CT and MRI revealed bilateral post-ischaemic lesions in the dorsomedial thalamus and the mesodiencephalic junction, dorsomedial to the red nucleus, thus being restricted to the territory of the posterior thalamosubthalamic paramedian artery, which includes the region of the rostral interstitial nucleus of the medial longitudinal fascicle as the main premotor nucleus for the generation of vertical saccades. In our patients, oculographic examination with electro-oculography and magnetic search coil recording showed severe impairment of downward more than upward saccades and only minor deficits of vertical pursuit and the vestibulo-ocular reflex. Visual functions were normal, with one exception: a psychophysical test of motion perception revealed a significant deficit in the detection of vertical movements. This could be due to a central adaptive mechanism which, in order to minimize oscillopsia, might elevate thresholds for vertical motion perception in cases of vertical gaze palsy. As an alternative explanation, lesions within the midbrain tegmentum could have damaged subcortical visual pathways involved in motion perception.
我们报告了两例急性起病的垂直凝视麻痹病例，主要表现为下视障碍和向下头部运动失用，同时伴有神经心理学缺陷（嗜睡、注意力受损以及记忆和情感控制障碍）。CT和MRI显示双侧丘脑背内侧和中脑间脑交界处存在缺血后病变，位于红核背内侧，因此局限于丘脑底丘脑旁正中后动脉供血区域，该区域包括内侧纵束吻侧间质核，它是产生垂直扫视的主要运动前核。在我们的患者中，通过眼电图和磁搜索线圈记录进行的眼动图检查显示，下视扫视的严重受损程度超过上视扫视，垂直跟踪和前庭眼反射仅有轻微缺陷。视觉功能正常，但有一个例外：一项运动感知的心理物理学测试显示，垂直运动检测存在显著缺陷。这可能是由于一种中枢适应性机制，为了尽量减少视振荡，在垂直凝视麻痹的情况下可能会提高垂直运动感知的阈值。另一种解释是，中脑被盖内的病变可能损害了参与运动感知的皮质下视觉通路。
