n=21, no control group, zero blinding. Placebo response is notoriously high in depression studies, so it's unacceptable that they didn't include a control group.
This technique is a variant of rTMS, which has been around for a long time. We've had years of positive rTMS study results that failed to replicate in real-world conditions. There's some early evidence that it might do something positive, but it's not clear that it's a viable treatment option. In most major cities you can usually find at least one obscure rTMS clinic somewhere, but they won't offer the exact rTMS technique studied here. They also won't give you 50 sessions across 5 days as used in this study.
It's very disappointing, even suspicious, that they didn't include a control group. It's trivially easy to include a sham rTMS treatment because the patients can't see the magnetic field. At minimum, they could have split the group into low-dose and high-dose to demonstrate a dose-response relationship. Yet they deliberately chose to avoid any control group or dose-response measurements.
I can't access the full text, so I don't know when they measured the patients' depressive symptoms. If they scored the depression inventory on the final day of the 5-day treatment, this wouldn't be very promising as a long-term treatment. The real test would be how the depression remission holds up after the rTMS treatment is discontinued. If the remission persists for months, that would be truly impressive. On the other hand, if this only works with 50 in-office rTMS sessions per week, it's not a practical outpatient treatment.
I would love to be wrong and for this to be the holy grail of depression treatment, but given the circumstances I think it's best interpreted as an outlier study unless/until someone else reproduces it. I don't think we'll all be going in for 50 sessions of rTMS across 5 days any time soon.