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Stimulus intensity determined by dose-titration versus age-based methods in electroconvulsive therapy in Thai patients

Authors Ittasakul P, Likitnukul A, Pitidhammabhorn U, Waleeprakhon P, Goldman MB

Received 14 September 2018

Accepted for publication 4 January 2019

Published 7 February 2019 Volume 2019:15 Pages 429—434


Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Amy Norman

Peer reviewer comments 3

Editor who approved publication: Dr Yu-Ping Ning

Pichai Ittasakul,1 Apichaya Likitnukul,1 Umporn Pitidhrammabhorn,1 Punjaporn Waleeprakhon,1 Morris B Goldman2

1Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 2Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA

Objectives: This study aimed to compare the accuracy of the stimulus intensity (SI) calculated by age-based methods with that using the dose-titration method.
Methods: The initial seizure threshold (IST) was determined using a standardized dose titration in hospitalized Thai patients treated with right unilateral (RUL, n=32) and bilateral (BL, n=57) electrode placement. The correlation between the IST and clinical variables was analyzed. The estimated SI based on the patient’s age was compared with the SI determined by dose titration.
Results: Age was highly predictive of the IST for both groups (RUL, P=0.012; BL, P=0.045). Gender (P=0.006) and anticholinergic drug use (P=0.025) predicted the IST for the BL group. For the RUL group, the mean±SD (median) SI estimated using the half-age and age methods was 158±46 (169) mC and 315±92 (338) mC, respectively. The SI determined using the dose-titration method was higher compared with the half-age method and lower compared with the age method. For the RUL group, 31% of subjects using the half-age method and 22% of subjects using the age method would have received an SI within ±20% of that computed using dose titration. Additionally, 19% of subjects using the half-age method and 19% using the age method would have received unacceptably low (<50%) or high (>200%) intensities. For the BL group, 18% of subjects using the half-age method and 32% using the age method would have received an SI within ±20% of that computed using dose titration. Additionally, 39% with the half-age method and 18% with the age method would have received an unacceptably low or high SI, respectively.
Conclusion: Age strongly predicts the IST, but it does not robustly predict the SI compared with dose titration because the SI calculated using age-based methods results in an unacceptably low or high SI that is associated with a marked risk of adverse effects or inadequate response. We recommend the dose-titration method to determine the SI.

Keywords: electroconvulsive therapy, dosing, Thai patients, dose titration, age-based methods, seizure threshold, predictors

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