Quantification of EEG changes following electroconvulsive therapy in depression

Abstract

Frequency analysis of EEG was made during electroconvulsive therapy (ECT) in patients with depression. Acute effects were quantified by calculating differences of EEG power from before to after the induced seizure, and were found to correlate with the duration of the seizure but not with the time lapse following the seizure. Increases in delta power were much more pronounced at the end of the treatment series than at the beginning. Non-acute effects were quantified as the differences from before the first treatment to the pre-ECT EEG later in the series. Increases in delta power correlated with the accumulated seizure duration and positively with the time lapse from the previous seizure, suggesting that it takes considerable time for this effect to develop. The concept of two different sources of EEG slowing during the ECT series is supported by different correlations between acute and non-acute EEG slowing on the one hand and on the other symptoms of depression, anxiety, cognitive disturbances, and cerebral blood flow as presented elsewhere.

Effect of a Course of Electroconvulsive Therapy on Interictal Bispectral Index Values

“…Specifically, there is an increase in the amount of slow wave activity, 13,14 which is frontally predominant. 15,16 Further, these changes are more prominent with bilateral than with unilateral ECT, 14,17 and the amount of EEG slowing is correlated with the number of ECT sessions. In our study, we have not directly examined the EEG changes through the course of ECT.…”

A Pilot Study of Possible Easy-to-Use Electrophysiological Index for Early Detection of Antidepressive Treatment Non-Response

“…Three of these patients did not comply with the requirement for repeated sampling and withdrew in the first 2 weeks. The fourth patient was excluded after about 2 weeks of sampling because it was found that, along with the pharmacological treatment change, he also started electroconvulsive treatment (ECT), which affects EEG significantly (18). Participants were recruited through the practicing physicians in the two medical centers.…”

Electroconvulsive Therapy: A Model for Seizure Detection by a Wavelet Packet Algorithm

“…According to changes in frequency content of the EEG recordings used in this study, two frequency bands (0.5 to 1.7 Hz and 1.8 to 5 Hz) were chosen to extract a feature discriminating between seizure and non-seizure periods. These frequency bands lay in the delta (~0.5 to 4 Hz) and theta (~4 to 8 Hz) bands where most EEG spectrum changes occur during ECT [13].…”