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Stimulus intensity, seizure threshold, and seizure duration: impact on the efficacy
and safety of electroconvulsive therapy.
Abstract: There has been considerable uncertainty in the clinical community on how stimulus dose, seizure
threshold, and seizure duration relate to the efficacy and side effects of electroconvulsive therapy (ECT). This
article reviews the evidence bearing on these issues. Recent evidence contradicts a number of long-standing views
about how to optimize ECT administration. Among these recent observations are findings that (1) generalized
seizures that are "adequate" by conventional duration criteria may be produced reliably, yet lack therapeutic
properties; (2) the degree to which stimulus intensity exceeds seizure threshold is critical in determining the
efficacy of unilateral ECT and also the speed of response with both unilateral and bilateral ECT; (3) the degree to
which electrical dose exceeds seizure threshold, not the absolute dose administered, determines dosing effects on
clinical outcome and on the magnitude of cognitive deficits; (4) there is marked variability among patients in their
seizure thresholds that is related reliably to patient characteristics (sex, age) and treatment factors (electrode
placement); and (5) seizure duration alone should not serve as a marker of the adequacy of treatment--there are
complex relations between stimulus dosing and seizure duration, with the likelihood that substantially
suprathreshold stimulation may result in shorter durations particularly early in the treatment course.
Author:
Sackeim HA
Devanand DP
Prudic J
Address: College of Physicians and Surgeons, Columbia University, New York, New York.
Abbreviated Journal Title: Psychiatr Clin North Am
Date Of Publication: 1991 Dec
Journal Volume: 14
Page Numbers: 803 through 843
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