Lack of pathologic changes in human temporal lobes after transcranial magnetic stimulation

Most animal studies have failed to demonstrate pathologic changes in the brain after transcranial magnetic stimulation (TMS). Nevertheless, vacuolar lesions in the cortex of rats after TMS have been reported. We report the first histopathologic studies of human brains after TMS in 2 patients with epilepsy who underwent temporal lobectomies. They had been involved in a study to determine the speech-dominant hemisphere by TMS and had received approximately 2,000 stimuli centered over the resected temporal lobe. Histologic study of the surgical specimens did not show any lesions attributable to TMS in these 2 patients.