STRENGTH SYMMETRY INDEX - A MEASURE OF SEIZURE ADEQUACY IN ECT

Seizure electroencephalography (EEG) was recorded from two channels-ri ght (Rt) and left (Lt)-during bilateral electroconvulsive therapy (ECT ) (n = 12) and unilateral ECT (n = 12). The EEG was also acquired into a microcomputer and was analyzed without knowledge of the clinical de tails. EEG recordings of both ECT procedures yielded seizures of compa rable duration. The Strength Symmetry Index (SSI) was computed from th e early- and midseizure phases using the fractal dimension of the EEG. The seizures of unilateral ECT were characterized by significantly sm aller SSI in both phases. More unilateral than bilateral ECT seizures had a smaller than median SSI in both phases. The seizures also differ ed on other measures as reported in the literature. The findings indic ate that SSI may be a potential measure of seizure adequacy that remai ns to be validated in future research.