Determinants of seizure threshold of electroconvulsive therapy in Chinese.

OBJECTIVE

Debates continue whether dose-titration, formula-based or fixed-dosage method should be used during ECT. Regardless of the dosing method used, the range and the determinants of seizure threshold in different ethnic groups are useful clinical information.

METHODS

Seizure threshold was quantified at the first ECT session using standardized dose titration and anesthetic protocols in 165 Chinese patients. One-hundred and five patients were treated with bilateral ECT and 60 with unilateral ECT.

RESULTS

The mean seizure threshold was 95.9 mC (range = 32-403 mC). The mean and range of seizure threshold for bilateral ECT were 115.1 mC and 48-403 mC, for unilateral ECT, the mean and range were 62.1 mC and 32-192 mC. Stepwise regression analysis showed that electrode placement and age were the two most important predictors of seizure threshold and accounted for 32 and 20% of its variance respectively. Of lesser significance greater body mass index and concurrent use of antiepileptic were associated with higher seizure threshold. Unlike previous Western studies, we showed that gender had no significant relationship with seizure threshold for the total sample and unilateral ECT while for bilateral ECT interpretation is limited by the higher starting dose in men.

CONCLUSIONS

Our finding added to the database on ECT in different ethnic groups and would be useful for the clinical practice of ECT in Chinese.