Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, India.
Clin EEG Neurosci. 2014 Apr;45(2):122-5. doi: 10.1177/1550059413487723. Epub 2013 Jun 11.
Electroconvulsive therapy (ECT), in which electrical current is used to induce seizures, is an effective treatment in psychiatry. Different methods of analyzing the electroencephalogram (EEG) changes during ECT have been studied for predicting clinical outcome. Analysis of the fractal dimension (FD) is one such method. Mid-seizure and post-seizure FD has been shown to correlate with antidepressant effect. In this study, we examined whether the highest fractal dimension achieved during each ECT session changed over the course of 6 ECTs. The sample for this study came from a randomized controlled trial, comparing the efficacy of bifrontal and bitemporal electrode placements in schizophrenia. EEG was recorded using bilateral frontal pole leads during all ECT sessions. In 40 of the 114 randomized patients, we could obtain artifact-free EEGs for the first 6 ECT sessions. FD was calculated using standardized algorithms. For each session, the average of 5 highest FDs was calculated. The change in this value over a course of 6 ECTs was analyzed using repeated-measures analysis of variance. The average highest FD remained virtually unchanged across the 6 ECT sessions. Means (standard deviations) average maximum FDs over the 6 sessions were 1.57 (0.075), 1.57 (0.064), 1.56 (0.064), 1.57 (0.062), 1.55 (0.07), and 1.56 (0.067); occasion effect, F = 0.5, P = .75. Group effect (F = 0.01, P = .92) and group × occasion interaction effect (F = 1.88, P = .1) were not significant, suggesting no influence of electrode placement on maximum FD. Seizure duration, however, showed significant decline over the course of ECT. Maximum FD of ECT-induced EEG seizure remains fairly constant over frontal poles across the first 6 ECT sessions, which is true irrespective of ECT electrode placements.
电抽搐治疗（ECT），即通过电流诱发癫痫，是一种有效的精神科治疗方法。已经有多种分析 ECT 过程中脑电图（EEG）变化的方法被用于预测临床疗效。分形维数（FD）分析就是其中之一。研究表明，发作中及发作后的 FD 与抗抑郁效果相关。在这项研究中，我们研究了在 6 次 ECT 过程中，每个 ECT 疗程中获得的最高 FD 是否发生变化。这项研究的样本来自一项比较精神分裂症患者双侧额极和双侧颞极电极放置的疗效的随机对照试验。在所有 ECT 疗程中，均使用双侧额极导联记录 EEG。在 114 名随机患者中，我们能够获得前 6 次 ECT 疗程中无伪影的 EEG。使用标准化算法计算 FD。对于每个疗程，计算 5 个最高 FD 的平均值。使用重复测量方差分析来分析 6 个疗程中该值的变化。在 6 个 ECT 疗程中，平均最高 FD 几乎保持不变。6 个疗程的平均最大 FD（标准偏差）分别为 1.57（0.075）、1.57（0.064）、1.56（0.064）、1.57（0.062）、1.55（0.07）和 1.56（0.067）；场合效应，F = 0.5，P =.75。组间效应（F = 0.01，P =.92）和组间×场合交互效应（F = 1.88，P =.1）均不显著，提示电极放置对最大 FD 没有影响。然而，癫痫持续时间在 ECT 过程中呈显著下降趋势。在前 6 次 ECT 疗程中，额极的 ECT 诱导 EEG 癫痫的最大 FD 相对保持恒定，无论 ECT 电极放置如何，均如此。
