99 subjects participated (60 female, 39 male). The participants were randomly assigned to one of three experimental groups, which determined the order and presence of the magnetic field exposure conditions: group 1 (sham exposure/sham exposure), group 2 (exposure/sham exposure), and group 3 (sham exposure/exposure).
|Setup||two octagonal Helmholtz coils consisting of 158 turns of 10-gauge copper wire and encased within plastic; 1.6 m wide and spaced 1.2 m apart parallel to each other; coils placed in a plastic frame, elevated 80 cm from the ground; non-conductive coolant tubing bordered the coils; participant seated between the coils, fitted with ear-plugs; field centered in the region of the participant's head and homogeneous within 5 % in this area|
|Sham exposure||A sham exposure was conducted.|
Performance between repetitions (the two (sham) exposure blocks) improved in 11 of 15 psychometric parameters (practice effect). A significant effect on the digit span forward test (see digit span test) revealed an absence of practice effects for both exposure groups but not the control group. This memory test indicates magnetic field-induced abolition of the improvement associated with practice. Overall, the data do not indicate any clear magnetic field effect on human cognition.