The Electroencephalographic Pattern during Electroconvulsive Therapy II. Preliminary Analysis of Spectral Energy

Abstract

Electroconvulsive therapy (ECT) is a safe and effective treatment for melancholic major depressive disorder (American Psychiatric Association, DSM-III). 1.2 Theseizures produced during ECT provide an excellent opportunity to study human electrical seizure activity unobscured by muscle and movement artifacts. Our previous reports of electroencephalograms recorded during ECT utilized visual analysis of paper (analog) recordings. 3 -5 Based upon such analysis, we have described three components of electrical seizures induced by ECT:Phase I -initial 14-22 Hz. rhythmic betalike activity Phase II -arhythmic polyspike activity Phase III -rhythmic 2%-3% Hz. spike/ polyspike wave activity We have been particularly interested in the asymmetric distribution of electrical seizure activity noted during Phase II, which becomes nearly symmetrical in Phase 111,4.5 of seizures induced by unilateral ECT stimulation. We now report preliminary computer analysis of portions of the EEG energy spectrum during Phases II and III of non-dominant hemisphere unilateral ECT seizures. MethodsA 30 year old male diagnosed as experiencing a severe major depressive episode (DSM-1I1 criteria) underwent a course of multiple monitored ECT given in five sessions on separate days over a two week period. Informed consent for this course of ECT was obtained from the patient. During the first, third, and fifth ECT sessions the patient was administered two electrically-induced seizures, while during the second and fourth sessions three seizures were induced. A total of twelve seizures were thus administered during these five sessions. The patient was given three different general anesthetics during this course of ECT, with ketamine (Ketalar) being used for the first three sessions, Innovar for the fourth, and methohexital (Brevital) for the final session. The patient received no psychotropic medication for at least three days prior to or during this course of ECT sessions. The patient was taken to the EEG suite where disc EEG electrodes were attached with collodian according to the International (10-20) EEG system (Figure 1). The recording electrodes were connected to a Grass Model 8-18 C multichannel EEG instrument.Once electrodes were in place, the patient was administered atropine 0.4 mg intravenously and an intravenous anesthetic agent. The initial anesthetic doses were ketamine 150 mg, methohexital 100 mg, or Innovar 7.0 cc. The patient was then paralyzed intravenously by a continuous drip of succinylcholine, with an average total dose of 125 mg per seizure. Unilateral nondominant hemisphere ECT impulses weredelivered using the techniques and Lancaster electrode positioning previously described.In addition to visual analysis of each paper tracing, the analog outputs from the EEG machine were recorded on an 8 channel FM instrumentation recorder with a tape speed of 19.05 em/sec (0-2500 Hz passband). The anterior fronto-temporal leads bilaterally (leads T4, F8, F4, F3, F7, and T3) and the two nasopharyngeal leads (Pg1 and Pg2) were selected for this re...

Cognitive and Neurophysiological Recovery Following Electroconvulsive Therapy: A Study Protocol

“…Additional measures will be calculated from windowed analyses of the high-density EEG: power spectral measures of the interval between anesthetic induction to delivery of ECT stimulus charge; the seizure envelope for 1–12 Hz EEG power; peak-to-peak amplitude, calculated from the difference in maximum and minimum voltages within 200 ms time; periodicity of epileptiform discharges; inter-hemispheric symmetry of seizure discharges; intra- and inter-hemispheric coherence. When possible, these measures and power spectral estimates will be derived from different phases of the ictal waveforms ( 27 ). The following postictal EEG measures will be assessed: duration and signal amplitude of postictal EEG suppression; power spectral parameters flanking the return of responsiveness to verbal command; and power spectral parameters from eyes open and closed epochs, including assessments of the posterior dominant rhythm.…”

“…Seizures will be staged according to the previously described phases that follow ECT stimulation (phase I with initial 14–22 Hz rhythmic beta activity, phase II with arrhythmic polyspike activity, and phase III with rhythmic 2.5–3.5 Hz. spike/polyspike activity 27 ). The duration and amplitude of post-ictal generalized EEG suppression (PGES) will also be determined.…”

“…Brief periods of EEG suppression or rhythmic bilateral 14-22 Hz oscillations may first emerge ( 21 ). Induction of bilateral poly-spike activity occurs, often with greater power on the side of the stimulation electrode in unilateral ECT ( 21 , 27 ). Spike/spike-and-wave complexes then arise, followed by termination within 3 min ( 21 , 26 ).…”