RÉSUMÉ
OBJECTIVES: In order to search for new parameters for the evaluation of the adequacy of electroconvulsive therapy (ECT) the authors performed a non-linear analysis of electroencepha-logram(EEG)recorded during the course of electroconvulsive therapy(ECT)in a single female patient with depression. METHODS: Digitized EEG recordings from two ECT sessions spaced one week were analyzed at five different stages; pretreatment stable, postanesthetic-preictal, ictal, postictal suppression and posttreatment stable stages. RESULTS: Our analysis showed that 1)EEG signals had low dimensional (below 10 dimensions) deterministic characteristics 2) although EEG was nonstationary signal, non-linear parameters could reliably differentiate between various stages we examined. 3)the deterministic property of ictal EEG increased according to the progression of sessions and 4)the primary Lyapunov exponent(PLE)and correlation dimension of pre- and post-treatment stable stage EEG increased according to the progression of sessions. CONCLUSION: In this single case study, results of various non-linear analyses suggested that non-linear variables extracted from EEG recordings during ECT may have utilities as tools for the quantitative evaluation of ECT.