Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Brain. 2010 Dec;133(Pt 12):3541-51. doi: 10.1093/brain/awq241. Epub 2010 Sep 13.
Deviations of the subjective visual vertical in the roll or fronto-parallel plane occur commonly in disorders of the brainstem and have been extensively explored. In contrast, little is known about deviations in other directions. The present retrospective study focused on deviations in the pitch (sagittal) direction in 176 patients with a wide variety of disorders. The test task was to set a self-illuminated rod in the apparent upright position, in total darkness. Abnormal results (outside ± 4°) were recorded in 58% of the subjects. Negative (top backward) deviations were the most common, particularly with mass lesions in the pineal region, obstructive hydrocephalus, cerebellar lesions and crowding at the craniocervical junction. Positive and negative deviations were about equally common with focal intra-axial lesions. Negative deviations appeared related to dorsal locations of lesions and vice versa. Normal pressure hydrocephalus, Parkinson's disease and progressive supranuclear palsy were associated with smaller deviations, without a clear directional preponderance, and a larger individual variability. Most subjects lacked overt clinical corollaries. The most common ocular signs were aqueduct syndromes (n = 17) and ocular tilt reactions (n = 12), which were associated with deviations in 47 and 92% of instances, respectively. Subjective corollaries of deviation were never reported, not even by those subjects who showed a dramatic improvement upon resolution of the underlying condition. Deviations were also assessed in roll in a subgroup of 40 patients with focal lesions. Thirty subjects returned abnormal results: 13% in roll, 47% in pitch and 40% in pitch and roll. The direction of roll deviation appeared primarily related to laterality, with clockwise deviations with right-sided lesions and vice versa. All subjects with ocular tilt reactions had combined pitch and roll deviations, implying a common neural substrate. Correlation analyses, geometrical modelling and experimental self-observations indicated that deviations in pitch were attributable to cyclotorsional asymmetries between the eyes. The frequent co-existence of abnormal pitch and roll results implies that the true axis of deviation in focal brainstem disorders commonly falls outside traditional reference planes. The term 'visual upright in three dimensions' is suggested to identify unrestricted measurements, preserving the established term 'visual vertical' for measurements confined to the roll plane. Assessment of the visual upright in three dimensions provides a new, quantitative angle on brainstem disorders. The test appears useful for identifying a ubiquitous yet clinically silent feature of brainstem disease and also for monitoring the evolution of underlying conditions. More detailed explorations appear well motivated.
主观垂直视觉在滚转或额状面内的偏差在脑干疾病中很常见，已有广泛研究。相比之下，人们对其他方向的偏差知之甚少。本回顾性研究重点关注了 176 名患有各种疾病患者的矢状（俯仰）方向的偏差。测试任务是在完全黑暗的情况下，将自发光棒置于明显垂直位置。58%的受试者记录到异常结果（超出±4°）。负（向后上方）偏差最为常见，尤其是在松果体区域有肿块、梗阻性脑积水、小脑病变和颅颈交界处拥挤时。与局灶性脑内病变相比，正偏差和负偏差出现的频率大致相同。负偏差似乎与病变的背侧位置有关，反之亦然。正常压力性脑积水、帕金森病和进行性核上性麻痹与较小的偏差相关，没有明确的方向性优势，个体变异性较大。大多数患者缺乏明显的临床并发症。最常见的眼部体征是导水管综合征（n=17）和眼倾斜反应（n=12），分别与 47%和 92%的情况下的偏差相关。即使是那些在潜在疾病得到解决后明显改善的患者，也从未报告过偏差的主观结果。在局灶性病变的 40 名患者亚组中还评估了滚转时的偏差。30 名患者返回异常结果：13%在滚转，47%在俯仰，40%在俯仰和滚转。滚转偏差的方向似乎主要与偏侧性有关，右侧病变为顺时针偏差，反之亦然。所有有眼倾斜反应的患者均有俯仰和滚转的联合偏差，这意味着存在共同的神经基础。相关分析、几何建模和实验自我观察表明，俯仰偏差归因于眼之间的旋转变形不对称。俯仰和滚转结果异常的频繁共存表明，局灶性脑干疾病的真正偏差轴通常不在传统参考平面之外。建议使用“三维视觉垂直”一词来表示不受限制的测量，保留“视觉垂直”一词用于仅限于滚转平面的测量。三维视觉垂直的评估为脑干疾病提供了一个新的、定量的角度。该测试似乎可用于识别脑干疾病普遍存在但临床上无症状的特征，也可用于监测潜在疾病的演变。更详细的探索似乎很有意义。
