Ictal Quality Measures: More Data From Spain

Out on PubMed, from researchers in Spain, is this study:

Factors Predicting Ictal Quality in Bilateral Electroconvulsive Therapy Sessions.

de Arriba-Arnau A, Dalmau Llitjos A, Soria V, Savino S, Salvat-Pujol N, Curto J, Menchón JM, Urretavizcaya M.Brain Sci. 2021 Jun 12;11(6):781. doi: 10.3390/brainsci11060781.PMID: 34204783

The abstract is copied below:

In electroconvulsive therapy (ECT), ictal characteristics predict treatment response and can be modified by changes in seizure threshold and in the ECT technique. We aimed to study the impact of ECT procedure-related variables that interact during each session and might influence the seizure results. Two hundred and fifty sessions of bilateral ECT in forty-seven subjects were included. Seizure results were evaluated by two different scales of combined ictal EEG parameters (seizure quality index (SQI) and seizure adequacy markers sum (SAMS) scores) and postictal suppression rating. Repeated measurement regression analyses were performed to identify predictors of each session's three outcome variables. Univariate models identified age, physical status, hyperventilation, basal oxygen saturation, days between sessions, benzodiazepines, lithium, and tricyclic antidepressants as predictors of seizure quality. Days elapsed between sessions, higher oxygen saturation and protocolized hyperventilation application were significant predictors of better seizure quality in both scales used in multivariate models. Additionally, lower ASA classification influenced SQI scores as well as benzodiazepine use and lithium daily doses were predictors of SAMS scores. Higher muscle relaxant doses and lower applied stimulus intensities significantly influenced the postictal suppression rating. The study found several modifiable procedural factors that impacted the obtained seizure characteristics; they could be adjusted to optimize ECT session results.

Keywords: bilateral ECT; electroconvulsive therapy (ECT); electroencephalography; hyperventilation; ictal adequacy; oxygen; postictal suppression; regression analysis; seizure quality; treatment outcome.

The pdf is here.

And from the text:

 Electroconvulsive therapy (ECT) is a high-value treatment for psychiatric illnesses

that provides great response rates in a quick manner and improves patient health-related quality of life.

An effective acute ECT treatment course consists of multiple, usually 6 to 12, adequate sessions. The adequacy of the generalized seizure induced in ECT sessions was initially linked to the seizure duration, which was associated with therapeutic and cognitive outcomes. However, the duration alone is not considered a reliable predictor of seizure adequacy and outcomes. ECT has proven to be equally clinically effective when using antiepileptic drugs, benzodiazepines, or propofol, which shorten seizure length. On the other hand, longer seizures do not directly influence the need for fewer ECT treatments. Moreover, it is known that seizure length increases when stimulus energy applied is too close to the seizure threshold, although it is a low-quality seizure, and right unilateral ECT can produce seizures with poor therapeutic potency despite being of sufficient ictal duration if the dosage is not adequately suprathreshold. Thus, there is a growing interest in finding seizure quality markers other than ictal duration that can be evaluable in each ECT treatment session and that are tied to clinical improvements to assure session adequacy, to guide clinicians’ decisions along the ECT course, and to optimize the sessions. Currently, seizure characteristics related to the amplitude and shape of the ictal electroencephalogram (EEG) are used along with the duration.

This paper has loads of well-collected data. I particularly like the wording of the topic sentence of the introduction (see yellow highlight, above).

But the holy grail of seizure optimization via ictal quality measures remains elusive; these data provide few new conclusions. Without clinical correlation, there is not much to say.

They do confirm the utility of increased basal O2 saturation  and hyperventilation (the green gas is good in ECT) on improving seizure quality measures.

Followers of the seizure adequacy/EEG markers literature will want to read this paper in full, ~20 minutes.