Effects of stimulus parameters on motor seizure duration in electroconvulsive therapy

OBJECTIVE This study examined the effect of stimulus parameters on the occurrence of adequate seizures and reconsidered the factors related to motor seizure duration. METHODS The medical records of 187 patients who received ECT in Asan Medical Center from January 2007 to May 2014 were retrospectively reviewed. The starting stimulus dose was determined using a preselected-dose method and the cutoff value to determine the adequate motor seizure duration was 20-25 seconds. The association between seizure parameters and the occurrence of adequate seizure was assessed with logistic regression using a generalized estimating equation. RESULTS Age (P<0.001), use of mood stabilizers (P=0.002), and benzodiazepine (P<0.001) were significantly lower in sessions with an adequate seizure duration but use of antidepressants (P<0.001) and clozapine (P=0.025) were significantly higher in sessions with an adequate seizure duration. In the generalized estimating equation analyses, after adjustment for age, benzodiazepine dose, and lamotrigine use, charge (odds ratio [OR] =0.999; 95% confidence interval [CI], 0.998-1.000; P=0.005), and train duration (OR =0.632; 95% CI, 0.490-0.817; P<0.001) were significantly associated with the occurrence of adequate seizure. DISCUSSION Stimulus charge and train duration are significantly associated with motor seizure duration. However, train duration appears to have a greater effect on motor seizure duration. Additionally, age, benzodiazepine dose, and lamotrigine use independently affect motor seizure duration.