Letters to the Editor
How Relevant is Seizure Duration in Assessing the Effectiveness of Electroconvulsive Therapy?
Dear Editor:
Electroconvulsive therapy (ECT) is a highly effective treatment for major depression and other psychiatric disorders. The question of how to define a therapeutically adequate ECT treatment has been discussed from the early days of ECT (1) to the present (2). Although convention has required a minimum individual seizure duration of 15 to 25 seconds (3,4) or a total seizure duration of more than 200 seconds (5), the complex electrophysiological events involved in developing a generalized seizure make it problematic to link the therapeutic efficacy of ECT to seizure duration only. We describe the case of a patient with severe depression who completely recovered despite receiving ECT that generated only brief motor seizures.
Case Report
A woman aged 73 years presented with a sudden onset of depressed mood, insomnia, loss of appetite and interest, poor concentration, and low energy. She had stopped eating, remained in bed, and became unable to attend to her personal care. She also demonstrated severe mood-congruent paranoid delusions.
Becoming confused after 4 bifrontal ECTs, she received right unilateral (RUL) ECT with the maximum stimulus parameters (576 mC) available on the MECTA (Mecta Corporation, Lake Oswego, Oregon). Even with attempts to prolong the seizure duration by pretreatment with a neuroleptic, adequate hydration, and hyperventilation, we were able to obtain motor seizures of only limited duration (average 14 to 15 seconds, range 7 to 37 seconds), even though EEG seizures using generous criteria were longer (average 31.7 seconds, range 18 to 56 seconds).
Despite the short seizures, the patient demonstrated gradual improvement; she was discharged home euthymic and with normal cognition after 10 such treatments.
Although a requirement for minimum seizure times is the convention, the excellent response seen after our patient experienced seizures with shorter durations indicates that the therapeutic efficacy of ECT cannot be linked to seizure duration alone, at least in individual cases. The decision to continue or stop the course of ECT should be based on clinical observation rather than on the duration of seizures obtained individually or cumulatively.
References
1. Meduna L. Autobiography. Part 1. Convuls Ther 1985;1:43–57.
2. Krystal AD, Weiner RD. ECT seizure therapeutic adequacy. Convuls Ther 1994;10:153–64.
3. Mayur PM, Gangadhar BN, Janakiramaiah N, Subbakrishna DK. Motor seizure monitoring during electroconvulsive therapy. Br J Psychiatry 1999;174:270–2.
4. Stern L, Dannon PN, Hirschmann S, Schriber S, Amytal D, Dolberg OT, and others. Aminophylline increases seizure length during electroconvulsive therapy. J ECT 1999;15:252–7.
5. Bean GJ, Marchese V, Martin BA. Electric stimulus energy and the clinical response to electrocon- vulsive therapy. Can J Psychiatry 1991;36:637–44.
Gaby Abraham, MD, FRCPC
Nick J Delva, MD, FRCPC
Kingston, Ontario
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