Noninvasive Brain Stimulation Techniques and Their Efficacy in Treating Cognition and Memory in Mild Cognitive Impairment and Alzheimer's Disease-A Systematic Review.

BACKGROUND/OBJECTIVES: The growing aging population is susceptible to cognitive and memory impairment, most commonly due to Alzheimer's disease, with no cures currently available. Noninvasive brain stimulation (NIBS) techniques may serve to improve cognition and delay catastrophic memory loss. METHODS: A systematic review of NIBS research on cognitive impairment was carried out using PubMed, with additional backward citation searching. A total of 81 studies using NIBS were included. CONCLUSIONS: The reviewed studies show that NIBS holds promise in improving memory deficits in patients with cognitive impairment. While the longevity of benefits from transcranial electrical stimulation appears limited, its short-term effects may provide benefits when used consistently. Transcranial magnetic stimulation appears to provide longer-lasting benefits. Transcranial focused ultrasound stimulation may also provide further benefits through more precise targeting of deeper brain structures compared to other NIBS techniques. Together, these results suggest that NIBS shows promise for the treatment of symptoms related to cognitive and memory impairment, and may help to alleviate some of the growing issues associated with the increasing level of Alzheimer's disease in an aging population.