Central-positive Complexes in ECT-induced Seizures: EEG Study From Wash U. St. Louis

Out on PubMed, from investigators at Washington University in St. Louis, is this study:

Central-positive complexes in ECT-induced seizures: Possible evidence for thalamocortical mechanisms.

Huels ER, Kafashan M, Hickman LB, Ching S, Lin N, Lenze EJ, Farber NB, Avidan MS, Hogan RE, Palanca BJA.Clin Neurophysiol. 2022 Dec 9;146:77-86. doi: 10.1016/j.clinph.2022.11.015. Online ahead of print.PMID: 36549264

The abstract is copied below:

Objective: Central-positive complexes (CPCs) are elicited during electroconvulsive therapy (ECT) as generalized high-amplitude waveforms with maximum positive voltage over the vertex. While these complexes have been qualitatively assessed in previous literature, quantitative analyses are lacking. This study aims to characterize CPCs across temporal, spatial, and spectral domains.

Methods: High-density 64-electrode electroencephalogram (EEG) recordings during 50 seizures acquired from 11 patients undergoing right unilateral ECT allowed for evaluation of spatiotemporal characteristics of CPCs via source localization and spectral analysis.

Results: Peak-amplitude CPC scalp topology was consistent across seizures, showing maximal positive polarity over the midline fronto-central region and maximal negative polarity over the suborbital regions. The sources of these peak potentials were localized to the bilateral medial thalamus and cingulate cortical regions. Delta, beta, and gamma oscillations were correlated with the peak amplitude of CPCs during seizures induced during ketamine, whereas delta and gamma oscillations were associated with CPC peaks during etomidate anesthesia (excluding the dose-charge titration).

Conclusions: Our findings demonstrate the consistency of CPC presence across participant, stimulus charge, time, and anesthetic agent, with peaks localized to bilateral medial thalamus and cingulate cortical regions and associated with delta, beta, and gamma band oscillations (depending on the anesthetic condition).

Significance: The consistency and reproducibility of CPCs offers ECT as a new avenue for studying the dynamics of generalized seizure activity and thalamocortical networks.

Keywords: Brain stimulation; Electroconvulsive therapy; Electroencephalography; Generalized seizure; Major depressive disorder; Thalamocortical network.

The article is here.

And from the text:

So here's a study done at the Barnes-Jewish Hospital in St. Louis Missouri that uses ECT as a model to indirectly study seizure propagation in the brain. It is a sub-study of an investigation on the recovery of cognitive function following ECT.

Talk about complex (pun intended) and neurological! I approached this paper with fear and loathing, but came away delighted. It is clearly and beautifully presented. Wow! : 64-electrode montages in 11 patients during 50 ECT-induced seizures. The findings tie "peak voltage of CPCs (central-positive complexes) to deep midline regions of the cingulate gyrus and superior midline thalamus...[and thus] implicate thalamocortical networks."

The potential benefits of this work extend beyond ECT to furthering understanding of epilepsy and brain mechanisms underlying major psychiatric illnesses.

Kudos to this interdisciplinary group of investigators for such an excellent contribution to the ECT EEG literature. A recommended full read will be ~ 30 minutes.