Change in seizure threshold during electroconvulsive therapy

The seizure threshold (ST) is a measure of the minimum electrical energy necessary to induce a grand mal seizure. Dose titration of the ST has been suggested to optimize stimulus dosing in electroconvulsive therapy (ECT). The change in ST with remission is examined in a large sample of unipolar depressed patients. METHODS: In a study of continuation treatments after successful ECT, the ST was determined at the first treatment and again 1 week after remission using a conventional ST measurement protocol. Patients were treated with bilateral electrode placement at 150% above the measured ST. RESULTS: In 80 subjects, the ST measured the same in 70%, increased in 21%, and decreased in 9% at remission. CONCLUSIONS: In a study of bilateral ECT, the ST did not rise conclusively with remission.