title: Seizure threshold increases can be predicted by EEG quality in right unilateral ultrabrief ECT.
abstract: Increases in seizure threshold (ST) over a course of brief pulse ECT can be predicted by decreases in EEG quality, informing ECT dose adjustment to maintain adequate supra-threshold dosing. ST increases also occur over a course of right unilateral ultrabrief (RUL UB) ECT, but no data exist on the relationship between ST increases and EEG indices. This study (n = 35) investigated if increases in ST over RUL UB ECT treatments could be predicted by a decline in seizure quality. ST titration was performed at ECT session one and seven, with treatment dosing maintained stable (at 6-8 times ST) in intervening sessions. Seizure quality indices (slow-wave onset, mid-ictal amplitude, regularity, stereotypy, and post-ictal suppression) were manually rated at the first supra-threshold treatment, and last supra-threshold treatment before re-titration, using a structured rating scale, by a single trained rater blinded to the ECT session being rated. Twenty-one subjects (60%) had a ST increase. The association between ST changes and EEG quality indices was analysed by logistic regression, yielding a significant model (p < 0.001). Initial ST (p < 0.05) and percentage change in mid-ictal amplitude (p < 0.05) were significant predictors of change in ST. Percentage change in post-ictal suppression reached trend level significance (p = 0.065). Increases in ST over a RUL UB ECT course may be predicted by decreases in seizure quality, specifically decline in mid-ictal amplitude and potentially in post-ictal suppression. Such EEG indices may be able to inform when dose adjustments are necessary to maintain adequate supra-threshold dosing in RUL UB ECT.
authors.affiliation: School of Psychiatry, Black Dog Institute, University of New South Wales (UNSW), Hospital Rd, Randwick, Sydney, NSW, 2031, Australia.|Black Dog Institute, Sydney, NSW, Australia.
authors.forename: Verònica
authors.initials: V
authors.lastname: Gálvez
authors.affiliation: School of Psychiatry, Black Dog Institute, University of New South Wales (UNSW), Hospital Rd, Randwick, Sydney, NSW, 2031, Australia.|Black Dog Institute, Sydney, NSW, Australia.
authors.forename: Dusan
authors.initials: D
authors.lastname: Hadzi-Pavlovic
authors.affiliation: The Queen Elizabeth Hospital, Woodville South, SA, Australia.
authors.forename: Susan
authors.initials: S
authors.lastname: Waite
authors.affiliation: School of Psychiatry, Black Dog Institute, University of New South Wales (UNSW), Hospital Rd, Randwick, Sydney, NSW, 2031, Australia. colleen.loo@unsw.edu.au.|Black Dog Institute, Sydney, NSW, Australia. colleen.loo@unsw.edu.au.|Department of Psychiatry, St George Hospital, Sydney, NSW, Australia. colleen.loo@unsw.edu.au.
authors.forename: Colleen K
authors.initials: CK
authors.lastname: Loo
mesh_terms: D000328:Adult; D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology*; D004565:Electroconvulsive Therapy / Q000379:methods*; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000628:therapy; D008875:Middle Aged; D012640:Seizures / Q000503:physiopathology*
keywords: Electroconvulsive therapy; Increase; Right unilateral; Seizure quality; Seizure threshold; Ultrabrief