Introduction: High frequency repetitive transcranial magnetic stimulation (HF-rTMS) of the left dorsolateral prefrontal cortex (DLPFC) might be a promising strategy to treat depression, but not all patients show a positive outcome.
Objective: In this open study, we evaluate whether a favorable HF-rTMS treatment outcome could be predicted by baseline prefrontal brain glucose metabolism (CMRglc), measured by 18fluorodeoxyglucose positron emission tomography (18FDG-PET).
Methods: A sample of 21 antidepressant-free, treatment-resistant depression (TRD) patients of the melancholic subtype received 10 sessions of HF-rTMS delivered on the left DLPFC. Patients underwent a static 18FDG-PET before and after HF-rTMS treatment.
Results: Forty-three percent of the patients showed a reduction of at least 50% on their Hamilton Rating Scale for Depression scores. Higher baseline metabolic activities in the DLPFC and the anterior cingulate cortex (ACC) were associated with better clinical outcome. Successful HF-rTMS treatment was related to metabolic changes in subdivisions of the ACC (Brodmann areas 24 and 32).
Conclusion: This biological impact of HF-rTMS on regional brain CMRglc explains to some extent how HF-rTMS may improve moods in TRD patients. Larger sham-controlled HF-rTMS treatment studies are needed to confirm these results.