At Home Gamma tACS in Alzheimer's Disease (tACS@Home)

Brain oscillations are ubiquitous in the human brain and have been implicated in cognitive and behavioral states defined in precisely tuned neural networks. In neurodegenerative disorders, neurodegeneration is accompanied by changes in oscillatory activity leading to the emerging concept of neurological and psychiatric disorders as "oscillopathies". Alzheimer's disease, which accounts for the vast majority of age-related dementias, is characterised by a prominent disruption of oscillations in the gamma frequency band. The restoration of gamma oscillations by neural entrainment in animal models of Alzheimer's disease have shown a remarkable decrease in the pathological burden of amyloid and tau via increased microglial activity, resulting in a significant increase of cognitive performances. Transcranial alternating current brain stimulation (tACS), is a neurophysiological method of non-invasive modulation of the excitability of the central nervous system that is having an increasingly numerous spectrum of potential therapeutic applications. Recent studies have demonstrated the effectiveness of this method in modulating the natural frequencies of cerebral oscillation, underlying multiple cognitive processes such as verbal memory, perception and working memory. On the basis of these premises, the treatment with gamma tACS is proposed in patients affected by Alzheimer's disease. In this randomized, double-blind, sham-controlled study, followed by an open-label phase, the investigators will evaluate whether a 9- or 18-weeks treatment with gamma tACS over the precuneus, delivered at home, can improve symptoms in patients with mild Alzheimer's disease. Subjects will be randomized in two groups in the first part of the trial. One group will receive a two-months treatment with gamma tACS (40 Hz) over the precuneus while the other group will receive placebo (sham) stimulation. After two-months, both group will undergo real stimulation (open-label phase) with gamma tACS (40 Hz) over the precuneus for two-months. Modulators of response will be considered.