title: The Clonic Phase of Seizures in Patients Treated with Electroconvulsive Therapy is Related to Age and Stimulus Intensity.
abstract: BACKGROUND
  Electroconvulsive therapy (ECT) is effective in the treatment of major depressive disorder and schizophrenia in patients who are drug-naïve or less-receptive to antipsychotic drugs. Several studies have discussed the correlation between patient characteristics, input-current volume, and seizure duration. According to the present principle of ECT guidelines, the therapeutic effect of ECT mostly correlates with seizure duration. As the tonic phase is different from the clonic phase with respect to brain function and activity, it is informative to analyze both the tonic and clonic phases. Thus, this study sought to clarify the relationship between the features of the two phases, and to re-examine and refine guidelines regarding ECT treatment.
  
  
  METHODS
  ECT-course data from 44 schizophrenia or bipolar I patients were recollected, including the number of treatments that they had received, their gender, age, and the association of these characteristics with motor seizure duration was analyzed. A two-factor correlation was employed to test the relationship between each of the two factors.
  
  
  RESULTS
  The post-analysis results indicate that seizure duration and age are significantly correlated. Older patients had relatively short seizure durations after ECT-treatment. Notably, a negative correlation was only found between age and the clonic phase of the seizure, not between age and the tonic phase. Furthermore, this study also found an inverse relationship between ECT-intensity and the clonic phase, but not between ECT-intensity and the tonic phase.
  
  
  CONCLUSIONS
  This study demonstrated that age and ECT-intensity are negatively correlated with seizure duration, particularly in the clonic phase. The present observations are not fully consistent with the basic guidelines of the APA-ECT practical manual. Accordingly, the predictions regarding the therapeutic effect of ECT can be based on both the seizure duration and the clonic phase.
authors.affiliation: Department of Psychology, National Chung Cheng University , Chiayi , Taiwan ; Department of Psychology, Soochow University , Taipei , Taiwan.
authors.forename: Chao-Chih
authors.initials: CC
authors.lastname: Wang
authors.affiliation: Department of Psychology, Soochow University , Taipei , Taiwan ; Biomedical Engineering R&D Center, China Medical University Hospital , Taichung , Taiwan ; Biomedical Electronics Translational Research Center, National Chiao Tung University , Hsinchu , Taiwan ; Department of Psychology, Kaohsiung Medical University , Kaohsiung , Taiwan.
authors.forename: Ching-Hung
authors.initials: CH
authors.lastname: Lin
authors.affiliation: Department of Psychology, Soochow University , Taipei , Taiwan.
authors.forename: Yao-Chu
authors.initials: YC
authors.lastname: Chiu
authors.affiliation: Department of Psychiatry, Beitou Branch, Tri-Service General Hospital, National Defense Medical Center , Taipei , Taiwan ; National Taipei University of Nursing and Health Sciences , Taipei , Taiwan.
authors.forename: Chih-Chieh
authors.initials: CC
authors.lastname: Tseng
keywords: age; clonic phase; electroconvulsive therapy; seizure duration; tonic phase