Krystal A D, Zaidman C, Greenside H S, Weiner R D, Coffey C E
Department of Psychiatry, Duke University Medical Center, Durham, NC 27710, USA.
Electroencephalogr Clin Neurophysiol. 1997 Dec;103(6):599-606. doi: 10.1016/s0013-4694(97)00062-x.
Attributes of the electroencephalogram (EEG) recorded during electroconvulsive therapy (ECT) seizures appear promising for decreasing the uncertainty that exists about how to define a therapeutically adequate seizure. In the present report we study whether one promising and not yet tested ictal EEG measure, the largest Lyapunov exponent (lambda1), is useful in this regard. We calculated lambda1 from 2 channel ictal EEG data recorded in 25 depressed subjects who received right unilateral ECT. We studied the relationship of lambda1 to treatment therapeutic outcome and to an indirect measure of treatment therapeutic potency, the extent to which the stimulus intensity exceeds the seizure threshold. We found lambda1 could be reliably calculated from ictal EEG data and that the global mean, maximum, and standard deviation of lambda1 were smaller in the more therapeutically potent moderately suprathreshold ECT and in therapeutic responders. These results imply a more predictable or consistent pattern of EEG seizure activity over time in more therapeutically effective ECT seizures. These findings also suggest the promise of lambda1 as a marker of ECT seizure therapeutic adequacy and build on our previous work suggesting that lambda1 may be useful for classifying seizures and for reflecting the relative physiologic impact of seizure activity.
在电休克治疗（ECT）发作期间记录的脑电图（EEG）特征，对于减少在如何定义治疗上足够的发作方面存在的不确定性似乎很有前景。在本报告中，我们研究一种有前景但尚未经过测试的发作期脑电图测量指标——最大李雅普诺夫指数（lambda1）在这方面是否有用。我们从25名接受右侧单侧ECT的抑郁症患者记录的双导联发作期脑电图数据中计算了lambda1。我们研究了lambda1与治疗效果以及与治疗效力的间接测量指标（即刺激强度超过发作阈值的程度）之间的关系。我们发现可以从发作期脑电图数据可靠地计算出lambda1，并且在治疗效力更强的中度阈上ECT以及治疗有反应者中，lambda1的总体均值、最大值和标准差更小。这些结果意味着在治疗效果更好的ECT发作中，随着时间推移脑电图发作活动的模式更可预测或更一致。这些发现还表明lambda1有望作为ECT发作治疗充分性的标志物，并且基于我们之前的工作，表明lambda1可能有助于对发作进行分类以及反映发作活动的相对生理影响。
