Transcranial Magnetic Stimulation in Alzheimer's Disease: Are We Ready?

Transcranial magnetic stimulation (TMS) is among a growing family of noninvasive brain stimulation techniques being developed to treat multiple neurocognitive disorders, including Alzheimer's disease (AD). Although small clinical trials in AD have reported positive effects on cognitive outcome measures, significant knowledge gaps remain, and little attention has been directed at examining the potential influence of TMS on AD pathogenesis. Our review briefly outlines some of the proposed neurobiological mechanisms of TMS benefits in AD, with particular emphasis on the modulatory effects on excitatory/inhibitory balance. On the basis of converging evidence from multiple fields, we caution that TMS therapeutic protocols established in young adults may have unexpected detrimental effects in older individuals or in the brain compromised by AD pathology. Our review surveys clinical studies of TMS in AD alongside basic research as a guide for moving this important area of work forward toward effective treatment development.