Advancements in Clinical Applications of Transcranial Magnetic Stimulation Using Different Coil Configurations: A Review

The effects of transcranial magnetic stimulation (TMS) are jointly determined by coil geometry, intracranial electric-field distribution, stimulation target, and pulse parameters, with coil design directly governing stimulation depth, spatial focality, and brain tissue coverage. This review compares circular, figure-of-eight, double-cone, and H-coils in terms of geometry, electric-field distribution, effective depth, focality, and current clinical use. Figure-of-eight coils provide high superficial focality and are suited to anatomically defined cortical targets such as the dorsolateral prefrontal cortex, primary motor cortex, and supplementary motor area. Double-cone and H-coils extend effective electric-field coverage to medial and relatively deep networks but reduce spatial selectivity, illustrating the depth–focality trade-off. The maturity of clinical evidence varies across disorders. Conventional repetitive TMS, intermittent theta-burst stimulation, and H1-coil deep TMS have comparatively established evidence in depression, whereas stroke and migraine remain heterogeneous in terms of target selection, dose, and patient selection. Key challenges are to match individualized intracranial electric-field dose, disease-network targets, pulse sequences, and brain state. This work offers valuable guidance for researchers in related fields and professionals engaged in the clinical management of neuropsychiatric disorders.