Comparison of Bifrontal and Bitemporal Electroconvulsive Therapy in Patients with Major Depressive Disorder

Article excerpt

Objective: The current study was conducted to compare the efficacy and side effects of bifrontal electrode placement with standard bitemporal electrode placement in the treatment of patients with major depression.

Method: Eighty nine patients with major depression were treated with a course of bifrontal or bitemporal ECT. All patients received 8 sessions of ECT treatment; and the Hamilton Rating scale for Depression and the standardized Mini-Mental state were administered 24 hours prior to the first session and 24 hours after the last session. This study was a Double Blind Randomized Clinical Trial.

Results: 68 of the 89 patients completed the study in the two groups of bifrontal (31 patients) and bitemporal (37 patients). The mean decrease in the Hamilton Rating scale for Depression score after ECT was the same in the both groups and was about 20 (SD± 3/2),showing a significant difference between the 2 groups. Nevertheless, the mean decrease in Mini-Mental state Examination score was different in the 2 groups and was 0/67 for the bifrontal ECT group (SD± 0/65) and 2/35 for the bitemporal ECT group (SD±0/94),, indicating a statistically significant difference(P<0/001).

Conclusion: The result of this study demonstrates that cognitive side effects of bifrontal ECT were significantly lower than bitemperal ECT ; however, the two methods are the same with regards to efficacy .

Keywords: Electroconvulasive therapy, Major depressive disorder, Methods

Iran J Psychiatry 2009; 4:13-16

Electroconvulsive therapy has evolved in many respects over the past 70 years since its introduction and remains our most effective treatment for major depression. In 1938, chemical induction methods were superseded by electrical induction. In the 1950s, the introduction of general anesthesia reduced morbidity from the treatment.

The move from sine wave electroconvulsive therapy (ECT) to brief pulse stimulation during the 1980s greatly reduced the severity of cognitive side effects of the treatment and provided the first clear demonstration that the type of electrical current applied to the scalp was a major determinant of side effects (1-4).

Recent research has extended that finding by demonstrating that electrode placement interacts with electrical dosage in determining efficacy as well as side effects (2).

ECT is the most effective treatment for severe depression (American Psychiatric Association, 2001)

Despite many evolutions in ECT methodology, the main limitation of ECT is cognitive side effects, particularly memory dysfunction. Memory impairment in ECT may be related to focal involvement of the dominant temporal lobe (5).

Variations in treatment technique, such as electrode placement and stimulus dose, have been investigated to maximize therapeutic efficacy while minimizing cognitive side effects. Right unilateral ECT causes significantly fewer memory side effects than bitemporal ECT but is less clinically effective unless the stimulus is increased to relatively high doses. Bifrontal ECT has been studied less extensively, and conlusive clinical efficacy data have not been available, however, preliminary reports suggest that it has similar or better anti-depressant efficacy compared to bitemporal ECT (6).

Bitemporal ECT, bifrontal ECT, and right unilateral ECT all induce a "generalized" tonic -clonic seizure; however, these different methods of stimulation result in different focal clinical, EEG, and imaging manifestations.

Bitemporal ECT activates focal bilateral frontotemporal and parietal association cortex, sparing other regions; bifrontal ECT mainly activates prefrontal cortex; in right unilateral ECT the left frontotemporal region is relatively spared(7).

Thus, the pattern of neuronal involvement during ECT is not homogenous throughout the brain, and it differs depending on stimulus configuration. Bitemporal ECT, Bifrontal ECT, and right unilateral ECT all differ in their clinical effects and cognitive side effects. …