Interest of targeting either cortical area Brodmann 9 or 46 in rTMS treatment for depression: a preliminary randomized study

Objective: To assess the interest of specifically targeting Brodmann Areas (BA) 9 or 46 for rTMS treatment of depression.

Methods: Patients with Treatment-Resistant Depression were randomly assigned to two treatment groups to receive either rTMS on BA 9 or on BA 46. Each patient underwent 10 sessions of 1Hz-rTMS for 2weeks. The Hamilton and Montgomery-Asberg Depression Rating Scales (HDRS, MADRS) were used under blind conditions to assess the therapeutic response (50% improvement). A Wilcoxon signed-rank test was used to compare the depression rating scales scores obtained before and after the 10 rTMS sessions for each of the two groups. The therapeutic results in the two groups were compared using the Mann-Whitney-Wilcoxon test. We also reported the effect sizes using Hedges's g.

Results: Fifteen patients were included. Stimulation of both BA 9 (n=7) and BA 46 (n=8) led to similar therapeutic responses in the two groups (with moderate effect size), such as the mean decrease in HDRS (BA 9: p=0.015; BA 46: p=0.010) and MADRS (BA 9: p=0.042; BA 46: p=0.038) scores.

Conclusion: Our results do not come out in favor of one or the other BA.

Significance: Stimulation of BA 9 and BA 46 appears to be equally effective in the treatment of depression.