Randomized comparison of cognitive function in humans at 0 and 8 Tesla

PURPOSE: To discover whether there was a measurable alteration in cognitive performance in humans when exposed to a static magnetic field of 8 Tesla (T). MATERIALS AND METHODS: Twenty-five normal human subjects were evaluated at both 0.05 and 8 T in a randomized order. Six standardized neuropsychological tests were administered and auditory reaction times were assessed. The cognitive assessment included measures of learning and retention, verbal fluency (spontaneous word generation), auditory attention, and auditory working memory. Alternate test forms were utilized to reduce practice effects. The sequential order of testing, 0.05 T first vs. 8 T first exposure, was randomized. The data was analyzed using univariate comparisons for correlated means to assess potential differences under the two conditions. RESULTS: There were no clinically significant differences in any of the measures. On a measure of recognition memory the subjects performed significantly better in the 0.05T condition, but the difference was extremely small, not clinically meaningful, and likely due to statistical artifact. CONCLUSION: This study shows that exposure of the brain to high magnetic fields of up to 8 T does not appear to alter human cognitive performance.