Structural and functional biomarkers of the effect of navigational repetitive transcranial magnetic stimulation in patients with drug-resistant depression

The use of high-frequency repetitive transcranial magnetic stimulation (rTMS) in patients with a drug-resistant depressive episode is associated with a high variability of its effect, which determines the relevance of the search for predictive biomarkers of the effect.Objective: to search for neuroimaging biomarkers of the clinical effectiveness of navigational rTMS in patients with a drug-resistant depressive episode.Patients and methods. The study included 30 patients with a drug resistant depressive episode who underwent 20 sessions of navigational highfrequency rTMS of the dorsolateral prefrontal cortex (DLPFC) of the left hemisphere. We performed an analysis of correlations between functional connectivity and gray matter volume (GMV) in given areas (before rTMS) with the degree of reduction in the Beck score for assessment of depression and the presence of a clinically significant response to therapy.Results and discussion. A relationship was shown between the clinical effect and low values of functional connectivity between the subgenual cingulated cortex and DLPFC of the right hemisphere. A relationship was found between a decrease in the severity of symptoms of depression and the volume of GMV in the insula, inferior frontal gyrus, temporal pole, superior temporal gyrus, and median cingulate cortex of the left hemisphere, as well as a relationship between the presence of a significant response to therapy and the volume of GMV in the insula, inferior frontal gyrus, temporal pole and superior temporal gyrus on the left.Conclusion. The obtained results may become a prerequisite for the development of individual predictive biomarkers of the effectiveness of rTMS in patients with a resistant depressive episode.