Are These Large Samples?

According to Transcranial magnetic stimulation: a new tool in the fight against depression:

During the year 2000, three relatively large studies (Grunhaus et al,³⁸ George et al,³⁷ and Pridmore et al⁴²) have reported significant antidepressant effects for rTMS administered over the LDLPFC. George et al conducted a parallel, double-masked, sham-controlled study of rTMS over the LDLPFC in patients with nondelusional MDD.³⁷

…

37. George MS., Nahas Z., Molloy M., et al. A controlled trial of daily prefrontal cortex TMS for treating depression. Biol Psychiatry. 2000;48:962–970. [PubMed]

38. Grunhaus L., Dannon P., Schreiber S., et al. Repetitive transcranial magnetic stimulation is as effective as electroconvulsive therapy in the treatment of nondelusional major depressive disorder: an open study. Biol Psychiatry. 2000;47:314–324. [PubMed]

…

42. Pridmore S., Raimondo B., Turnier-Shea Y., Reid P., Rybak M. Comparison of unlimited numbers of rapid transcranial magnetic stimulation (rTMS) and ECT treatment sessions in major depressive episode. Intj Neuropsychopharmacol. 2000;3:129–134. [PubMed]

When we look at the actual studies, we see in Ref. 37:

Thirty medication-free adult outpatients with nonpsychotic, major depressive (n = 21) or bipolar (n = 9) (depressed phase) disorder who were in a current major depression (Hamilton Rating Scale for Depression [HRSD] 21-item score of >18) were treated each weekday for 2 weeks. Subjects were randomly assigned to receive either daily active (20 subjects) or sham (10 subjects) stimulation. Additionally, the 20 active subjects were equally divided between slower (5 Hz) and faster (20 Hz) frequency treatment. Antidepressant response was defined as greater than a 50% improvement in the baseline HRSD.

and in Ref. 38:

Forty patients with MDD referred for ECT were randomly assigned to either ECT or rTMS.

and in Ref. 42:

We compared the antidepressant effects of rTMS and ECT in 32 patients suffering major depressive episode (MDE) who had failed to respond to at least one course of medication.

Neurobiologists have a different definition of large. To quote Sheldon Cooper, PhD:

Notify the editors of the Oxford English Dictionary: the word "plenty" has been redefined to mean "two".

and:

Oh, great. Now I’m worse than a fraud. I’m practically a biologist.