Sackeim and coworkers2 randomized 90 patients with depression to 1 of 4 treatment groups:
1. RUL at 6 times seizure threshold with a standard pulse-width of 1.5 milliseconds
2. RUL at 6 times seizure threshold with a pulse-width of ultrabrief 0.3 millisecond
3. Bilateral (BL) ECT at 2.5 times seizure threshold with a pulse- width of 1.5 milliseconds
4. BL ECT at 2.5 times seizure threshold with a pulse-width of 0.3 millisecond
Patients were assessed for depressive symptoms and cognition at baseline, during and after the acute course of ECT, and at 2 and 6 month time points. Responders were monitored for 1 year. Reported remission rates were 73% for ultrabrief RUL, 65% for brief pulse BL, 59% for brief pulse RUL, and 35% for ultrabrief BL. Ultrabrief pulse RUL produced less severe cognitive effects than the other 3 treatment groups, both acutely and long-term, on multiple measures in several cognitive domains, including subjective assessment of memory function. Relapse in the year following acute ECT was unrelated to treatment group. These authors concluded, “the use of an ultrabrief stimulus coupled with high-dosage RUL stimulation is a strategy that appears to retain the therapeutic properties of ECT, although substantially reducing its potential for adverse cognitive side effects.”
While the conclusions of these 3 studies are similar, some differences in methodology and results should be noted. The Sienaert study used BF placement at 1.5 times seizure threshold, while the Sackeim study used standard BL placement at 2.5 times seizure threshold. The latter strategy is likely to accentuate cognitive differences between the BL and RUL groups. The low remission rate in the Sackeim study of BL ultrabrief pulse ECT in 23 patients is surprising, at odds with the superior rate of the slightly different BF placement in the Sienaert study, and requires replication. Finally, pulse-widths used for “standard” brief pulse treatment varied between the Sackeim (1.5 milliseconds) and Loo (1.0 millisecond) studies.
These studies constitute an exciting and intriguing preliminary body of data. While these are the only readily accessible published data, undoubtedly there are more data out there. Because standard ECT devices used in the United States and around the world have had the capability to deliver ultrabrief pulse-widths for several years, many patients have been treated clinically with this modality—most likely with all 3 commonly used electrode placements (BL, BF, and RUL). Such anecdotal data may be helpful to provide hints about safety and effectiveness but cannot replace systematically collected data from clinical trials, randomized or naturalistic.
With fewer than 200 patients reported in these trials, is it reasonable to adopt ultrabrief pulse ECT in routine clinical practice? Are we sacrificing efficacy? Are ultrabrief pulse stimuli appropriate for use with BL electrode placements?
Further studies are needed to answer these questions. Such important questions beg the even more important question: “How much evidence is needed, in evidence-based medicine, to change clinical practice?” Ideally, the studies discussed would quickly lead to replications that would prove the point, one way or the other. Unfortunately, in ECT, the resources to conduct well-designed studies that would definitely answer the question are often unavailable. We are left with a smattering of data, not all collected with the best methodology, from which clinical decisions must be made.
Prudence and caution are always needed in clinical decision making, and we should clearly “first, do no harm.” But what is the greater harm? Depriving a seriously depressed patient of the most effective treatment, or exposing the patient to more cognitive impairment from the treatment?
There is no simple answer, but I suggest that we tell our patients that there is a new technique, about which less is known than more standard techniques, but one that has the potential to relieve depression with fewer memory effects. Thus included in the decision-making process, the practitioner and patient together can arrive at a treatment plan that is informed by the available, albeit limited, data. Fortunately, the nature of ECT is such that if, after several RUL treatments with ultrabrief pulse stimuli, the patient is not responding adequately, the treatment technique can be switched, either to a different waveform or electrode placement, or both.