Background: Electroconvulsive therapy (ECT) is a most effective treatment for patients with major affective disorders. The influence of anesthetic drugs on seizure "adequacy" or on treatment success has not been systematically investigated.
Methods: A bispectral EEG index score (BIS) was used to identify the depth of anesthesia during ECT. Our study included 22 major depressive episode (MDE) patients expanding to 219 ECTs (05/05-01/06) with no limitations of concurrent medication.
Results: Fourteen out of the 22 patients showed full remission. Individual number of ECT sessions needed to reach full remission correlated negatively with mean pre-ECT BIS values (p=0.001). Additionally, using a repeated measurement regression analysis significant correlations were found for pre-ECT BIS versus motor response time, seizure concordance, ictal coherence and peak heart rate.
Conclusion: The results of our study suggest BIS-levels as a predictor of faster ECT response. Controlling BIS-levels before stimulation may have an additional effect on treatment success.