Taubøll E, Lundervold A, Gjerstad L
Department of Neurology, Rikshospitalet, University of Oslo, Norway.
Epilepsy Res. 1991 Mar;8(2):153-65. doi: 10.1016/0920-1211(91)90084-s.
A major problem in epileptology is why a seizure occurs at a particular moment in time. An initial step in solving this problem is a detailed analysis of the temporal distribution of seizures. Using methods and theories of stochastic processes, seizure patterns in a group of epileptic outpatients were examined for stationarity, randomness, dependency and periodicity in a prospective study. Sixteen of the 21 seizure diaries included in the study showed stationarity; 2 were non-stationary and 3 inconclusive. Eleven of the 16 stationary diaries were non-Poisson (P less than 0.005), indicating that in the majority of patients seizures did not occur randomly. The most frequently encountered phenomenon was seizure clustering. Clustering was considered when the diaries fulfilled all three criteria: (1) a positive R-test (P less than 0.001); (2) deviation from the fitted Poisson distribution towards clustering; and (3) the feature of an autoregressive process in the autocorrelogram plot. Dependency between seizure events was demonstrated in 8 of the 16 stationary diaries, computing first order transition probabilities. A detailed analysis of seizure occurrence is a major step towards a better understanding of the mechanisms underlying seizure precipitation. This is exemplified by our finding of a relation between seizure frequency and the menstrual cycle.
癫痫学中的一个主要问题是为何癫痫发作会在特定时刻发生。解决这个问题的第一步是对癫痫发作的时间分布进行详细分析。在一项前瞻性研究中，运用随机过程的方法和理论，对一组癫痫门诊患者的发作模式进行了平稳性、随机性、依赖性和周期性的检查。该研究纳入的21份发作日记中，有16份显示出平稳性；2份为非平稳性，3份结果不明确。16份平稳性日记中有11份不符合泊松分布（P<0.005），这表明在大多数患者中，癫痫发作并非随机发生。最常出现的现象是发作聚类。当日记满足以下所有三个标准时考虑存在聚类：（1）R检验为阳性（P<0.001）；（2）偏离拟合的泊松分布而趋向聚类；（3）自相关图中呈现自回归过程的特征。通过计算一阶转移概率，在16份平稳性日记中的8份中证实了发作事件之间的依赖性。对癫痫发作发生情况进行详细分析是朝着更好地理解癫痫发作诱发机制迈出的重要一步。我们发现癫痫发作频率与月经周期之间存在关联就是一个例证。
