Cerebellar Transcranial Magnetic Stimulation: The Role of Coil Type from Distinct Manufacturers

Background Stimulating the cerebellum with transcranial magnetic stimulation is often perceived as uncomfortable. No study has systematically tested which coil design can effectively trigger a cerebellar response with the least discomfort. Objective To determine the relationship between perceived discomfort and effectiveness of cerebellar stimulation using different coils: MagStim (70 mm, 110 mm-coated, 110-uncoated), MagVenture and Deymed. Methods Using the cerebellar-brain inhibition (CBI) protocol, we conducted a CBI recruitment curve with respect to each participant’s maximum tolerated-stimulus intensity (MTI) to assess how effective each coil was at activating the cerebellum. Results Only the Deymed double-cone coil elicited CBI at low intensities (−20% MTI). At the MTI, the MagStim (110 mm coated/uncoated) and Deymed coils produced reliable CBI, whereas no CBI was found with the MagVenture coil. Conclusions: The Deymed double-cone coil was most effective at cerebellar stimulation at tolerable intensities. These results can guide coil selection and stimulation parameters when designing cerebellar TMS studies.