Objective.—Accurate and reproducible coil positioning is important for headache research using transcranial magnetic stimulation protocols. We aimed to design a transcranial magnetic stimulation coil holder and demonstrate reliability of test–retest coil positioning.
Methods.—A coil holder was developed and manufactured according to three principles of stability, durability, and three-dimensional positional accuracy. Reliability of coil positioning was assessed by stimulating over the motor cortex of four neurologically normal subjects and recording finger muscle responses, both at a test phase and a retest phase several hours later.
Results.—In all four subjects, repositioning of the transcranial magnetic stimulation coil solely on the basis of coil holder coordinates was accurate to within 2 mm.
Conclusions.—The coil holder demonstrated good test–retest reliability of coil positioning, and is thus a promising tool for transcranial magnetic stimulation-based headache research, particularly studies of prophylactic drug effect where several laboratory visits with identical coil positioning are necessary.