Frohman E M, Frohman T C, O'Suilleabhain P, Zhang H, Hawker K, Racke M K, Frawley W, Phillips J T, Kramer P D
Department of Neurology, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
J Neurol Neurosurg Psychiatry. 2002 Jul;73(1):51-5. doi: 10.1136/jnnp.73.1.51.
There is a poor correlation between multiple sclerosis disease activity, as measured by magnetic resonance imaging, and clinical disability.
To establish oculographic criteria for the diagnosis and severity of internuclear ophthalmoparesis (INO), so that future studies can link the severity of ocular dysconjugacy with neuroradiological abnormalities within the dorsomedial brain stem tegmentum.
The study involved 58 patients with multiple sclerosis and chronic INO and 40 normal subjects. Two dimensional infrared oculography was used to derive the versional dysconjugacy index (VDI)-the ratio of abducting to adducting eye movements for peak velocity and acceleration. Diagnostic criteria for the diagnosis and severity of INO were derived using a Z score and histogram analysis, which allowed comparisons of the VDI from multiple sclerosis patients and from a control population.
For a given saccade, the VDI was typically higher for acceleration v velocity, whereas the Z scores for velocity measures were always higher than values derived from comparable acceleration VDI measures; this was related to the greater variability of acceleration measures. Thus velocity was a more reliable measure from which to determine Z scores and thereby the criteria for INO and its level of severity. The mean (SD) value of the VDI velocity derived from 40 control subjects was 0.922 (0.072). The highest VDI for velocity from a normal control subject was 1.09, which was 2.33 SD above the normal control mean VDI. We therefore chose 2 SD beyond this value (that is, a Z score of 4.33) as the minimum criterion for the oculographic confirmation of INO. Of patients thought to have unilateral INO on clinical grounds, 70% (16/23) were found to have bilateral INO on oculographic assessment.
INO can be confirmed and characterised by level of severity using Z score analysis of quantitative oculography. Such assessments may be useful for linking the level of severity of a specific clinical disability with neuroradiological measures of brain tissue pathology in multiple sclerosis.
通过磁共振成像测量的多发性硬化症疾病活动与临床残疾之间的相关性较差。
建立核间性眼肌麻痹（INO）诊断及严重程度的眼动图标准，以便未来研究能够将眼球运动失调的严重程度与脑桥背内侧被盖区内的神经放射学异常联系起来。
该研究纳入了58例患有多发性硬化症和慢性INO的患者以及40名正常受试者。使用二维红外眼动图来得出版本失调指数（VDI），即外展眼与内收眼运动的峰值速度和加速度之比。通过Z评分和直方图分析得出INO诊断及严重程度的诊断标准，这使得能够对多发性硬化症患者和对照组人群的VDI进行比较。
对于给定的扫视，加速度的VDI通常高于速度的VDI，而速度测量的Z评分始终高于从可比加速度VDI测量得出的值；这与加速度测量的更大变异性有关。因此，速度是确定Z评分从而确定INO及其严重程度标准的更可靠指标。40名对照受试者得出的VDI速度的平均值（标准差）为0.922（0.072）。正常对照受试者速度的最高VDI为1.09，比正常对照平均VDI高出2.33个标准差。因此，我们选择超出该值2个标准差（即Z评分为4.33）作为眼动图确认INO的最低标准。在临床上被认为患有单侧INO的患者中，70%（16/23）经眼动图评估发现患有双侧INO。
可通过定量眼动图的Z评分分析来确认INO并对其严重程度进行分级。此类评估可能有助于将特定临床残疾的严重程度与多发性硬化症脑组织病理学的神经放射学测量联系起来。
