|Year : 2016 | Volume
| Issue : 2 | Page : 190-197
Effect of age and anticonvulsants on seizure threshold during bilateral electroconvulsive therapy with brief-pulse stimulus: A chart-based analysis
Abhishek R Nitturkar1, Preeti Sinha2, Virupakshappa I Bagewadi2, Jagadisha Thirthalli2
1 Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, Virginia 22908, USA
2 Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
Background: Efficacy and adverse effects of electroconvulsive therapy (ECT) depend on the extent to which the electrical stimulus exceeds patients' seizure thresholds (STs). Titration method of estimating ST is recommended. Age and co-prescribed anticonvulsants (ACs) are known to affect ST. Literature on ST in bilateral ECT (BLECT) is sparse.
Objective: To explore the clinical and demographic determinants of ST in a clinically representative sample of patients prescribed with BLECT.
Materials and Methods: ECT records of 640 patients who received BLECT in 2011 in an academic psychiatric setting were studied. Demographic, clinical, pharmacological, and ECT details were analyzed. As per the standard practice, during the 1st ECT session, ST was determined by titration method, starting with 30 milli-Coulombs (mC) and increasing by 30 mC and thence in steps of 60 mC. Increase in ST over up to 6th session of ECT was noted. Receiver operating characteristic curve was used to find age cut-off with high specificity for ST ≥120 mC. The associations of ST and increase in ST with the age cut-off and other clinical factors were assessed using Chi-square test and logistic regression analysis.
Results: The mean age was 30.98 years (+11.23 years) and mean ST at 1st ECT session was 130.36 mC (+51.96 mC). There was significantly high positive correlation (r = 0.37, P< 0.001) between age and ST. Cut-off age of 45 years had high specificity: Only 4.6% of those older than 45 years had ST <120 mC. Higher proportion of patients on AC had ST ≥120 mC. These associations were seen even after controlling for potential confounds of each other using logistic regression analysis. The results were similar for increase in ST over the course of ECT. Sex, diagnosis, use of antipsychotics, antidepressants, lithium, and benzodiazepines (BZPs) had no effect on ST or its increase.
Conclusions: For BLECT using brief-pulse stimulus, ST depends on age and use of AC. For patients above the age of 45 years, ST estimation may be started at 120 mC with least risk of using unduly higher stimulus. Other medications including BZPs have little influence on ST.
Dr. Preeti Sinha
Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru - 560 029, Karnataka
Source of Support: None, Conflict of Interest: None
[FULL TEXT] [PDF]*