Objective
Efficacy and cognitive outcome of ECT is depending on electrode placement, pulse width and electrical dosage. Several studies showed that high-dosage right unilateral ECT (RULECT) had a better antidepressant effects than low-dosage RULECT and less cognitive side effect than bilateral stimulation. In this prospective, randomized, double-blind trial, we examined the efficacy and cognitive side effects of RULECT with three different (high dose) stimulus intensities (4×, 7× and 10× above the seizure threshold (ST)).
Methods
41 patients with treatment resistant unipolar or bipolar depression were randomized to one of the three stimulation intensities. For stimulation, we used an ultrabrief pulse (0.3 ms). Primary outcome measures were reduction of the Hamilton Depression Rating Scale (HDRS), Beck Depression Inventory (BDI) and the response rate (50% reduction of the HDRS) in the three groups. For cognitive side effects, a neuropsychological test battery was assessed.
Results
All three groups responded significantly to 9 ECTs (p < 0.005), but there were no statistical significant differences in the response rates between the three intensity groups. Besides of the Verbal Learning Memory Recognition Test (VLMT), which showed significant impairments in the high dose intensity groups, no differences could be shown between the three study groups in all neuropsychological tests.
Conclusion
A RULECT with ultrabrief pulse stimulation and 4× ST intensity is effective and from good tolerability. Higher intensity dosages seem to be associated with more cognitive side effects during a course of acute ECT treatment.
Electroconvulsive therapy (ECT) is widely used to treat certain psychiatric disorders, particularly (psychopharmacotherapy-) resistant major depression. It is highly effective for treatment of Major Depression (2003). The most common and persistent adverse effect of ECT is cognitive impairment, particularly memory dysfunction, with the tendency to resolve in the first few months after discontinuation of treatment. The amnestic effects are greatest for impersonal memory compared with autobiographical memory (Lisanby et al., 2000), and, in addition, impairments of other cognitive domains like attention or executive function in patients undergoing acute ECT treatment have been observed (Ingram et al., 2008). Monitoring of cognitive side effects had turned out to be an important issue for clinicians, as they can potentially limit the course of a presumed adequate treatment trial and patients compliance within the treatment.
Regarding stimulation parameters, both efficacy and cognitive outcome of ECT is depending on electrode placement, pulse width and electrical dosage (Sackeim et al., 1993). In the past decades, modifications of stimulation parameters were examined to minimize cognitive side effects while maintaining efficacy: first, it was shown that right unilateral ECT (RULECT) is accompanied with less cognitive side effect than bilateral ECT (Sackeim et al., 2000). Second, modification of pulse form to rectangular brief pulses and introduction of stimulation techniques with ultrabrief pulse (0.3 ms) lead to an improvement of adverse effect profile (Geddes, 1987) in comparison to a traditional brief pulse (1.5 ms) (Sackeim et al., 2008). These results were confirmed in study of Loo et al. (2008): cognitive outcomes were superior when using ultrabrief pulse stimulation, particular to the verbal memory, as well as in retrograde autobiographical memory. These findings favour ultrabrief pulse RULECT as the most tolerable form of treatment (Prudic, 2008). Third, it had been shown that the increase of stimulation intensity lead to an improvement of antidepressant efficacy, and at the same time to a worsened neurocognitive profile in a dose-dependant manner (Sackeim et al., 2000, McCall et al., 2002, Abrams et al., 1991 and Sackeim et al., 1993). However, to date, studies dealing with high intensity ultrabrief ECT are lacking. Therefore, we performed a prospective, randomized, double-blind trial, in which we examined efficacy and neurocognitive tolerability of 3 different (high dose) stimulus intensities (4× ST, 7× ST and 10× ST).
