[Strategies for optimizing stimulus dosage during electroconvulsive therapy].
Core element of electroconvulsive therapy (ECT) is the induction of a generalized seizure. Stimulus intensity must be above patient's seizure threshold for seizure induction. As individual seizure thresholds vary in a wide range, determining optimal initial stimulus intensity is a challenge to the clinician. In the literature four different methods are recommended for this purpose: 1) dose-titration 2) half-age method 3) age method 4) fix dose method.


OBJECTIVE
to determine the most optimal method out of these four for selecting initial stimulus dose for bilateral electroconvulsive therapy of patients with schizophrenia.


METHODS
40 patients with schizophrenia were treated with ECT during the studied period. Data of these treatments were analyzed retrospectively. Seizure threshold was determined with dose-titration in each case at the beginning of the treatment. Relationship between seizure threshold and age was investigated with the Pearson's correlation test.


RESULTS
Mean age of the studied population was 38.07+/-16.66 years. To eliciting a seizure duration of at least 20 sec, a mean stimulus intensity of 18.37% (92.61 mC)+/-8.35(42.08 mC) was required. The patient's age showed significant positive correlation (p less than 0,001) with stimulus intensity. EEG registered mean seizure duration was 39.65+/-17.78 s, and mean motoric seizure lasted for 32.45+/-17.24 s.


CONCLUSIONS
Variation between the lowest and the highest seizure threshold in our study was 6-fold. Having analyzed the different initial dosing strategies on the basis of the seizure thresholds observed in our study, we concluded that the age method seems to be the most optimal one for bilateral ECT of patients with schizophrenia.
Gazdag
Gábor
G
Fovarosi Onkormanyzat, Szent Laszlo Korhaza, Addiktologiai es Pszichiatriai Ambulancia, Budapest, Hungary. gazdag@lamb.hu
Tolna
Judit
J
Iványi
Zsolt
Z
D000328:Adult; D000367:Age Factors; D000368:Aged; D000768:Anesthesia, General; D014150:Antipsychotic Agents / Q000627:therapeutic use; D004565:Electroconvulsive Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012107:Research Design; D012189:Retrospective Studies; D012559:Schizophrenia / Q000188:drug therapy / Q000628:therapy*; D012640:Seizures
D014150:Antipsychotic Agents