P 49 Polysymptomatic TMS treatment with the H1 coil compared to the figure of 8 coil leads to more uniform changes across symptom clusters in patients with major depression disorder

Abstract

Question: A diagnosis of Major Depressive disorder (MDD) often indicates the presence of multiple symptoms and disorders. This is both because MDD itself is a heterogenous syndrome and because as with many psychiatric disorders, comorbidity is common. Effective treatments therefore must be able to treat these multiple symptoms. A recent publication showed that high frequency repetitive transcranial magnetic stimulation (rTMS) applied with a figure of 8 (F8) coil effects distinct clusters of symptoms in MDD patients differently depending on the placement of the coil (Siddiqi et al. 2020). While this finding is an important step in understanding the mechanism behind clinical rTMS, it also presents a tremendous challenge. Stimulating the target for each symptom cluster would require additional sessions to the current treatment protocol to treat each cluster in series. However, the authors hypothesize that a larger coil that stimulates all cluster targets simultaneously would be more effective at poly-symptomatic treatment by uniformly modulating multiple clusters. We test this hypothesis using data collected from the only head to head study of F8 and the broader H1 coils and tested whether the correlations of changes between clusters were higher for the H1 coil than the F8 coil. Methods: Data was collected from 137 MDD patients randomized to 20 sessions of H1 (n=65) or F8 coil (n=72). Patients received 10 Hz or 18 Hz stimulation for the F8 and H1 arms respectively at 120% MT (Filipčić et al. 2019). Questions from the HAM-D17 were clustered into dysphoric, anxiosomatic, and insomnia and the difference at the endpoint from the baseline of the average symptom severity in each cluster was calculated. Results: All pairwise correlation coefficients between changes in symptom cluster severity are significant for the H1 coil while only the correlation coefficient for the dysphoric with the anxiosomatic clusters is significant for the F8 coil. A z-score test shows that the higher correlation between the dysphoric and anxiosomatic clusters with the H1 (r = 0.54, p = 0.3*10-5) versus F8 coil (r = 0.32, p = 0.006) is nearly significant (p=0.058). Conclusions: While use of both coils leads to a reduction of severity in the symptom clusters across the patient population, the higher correlations between changes in symptom clusters seen with the H1 coil mean more uniform changes in individual patients. This is of notable practical importance as it allows for poly-symptomatic treatment even when only targeting the core symptoms of depression as first proposed by Siddiqi et al.