Digital Twins for Model-driven Non-invasive Electrical Brain Stimulation

The purpose of this study is to obtain preliminary data in advance of a larger clinical trial designed to test whether repeated, daily sessions of at-home transcranial alternating current stimulation (tACS) can lead to a clinically significant improvement in patients with AD. Given the potentially fragile patient population, the investigators propose a pilot study to test feasibility and safety (primary). In this pilot study 30 mild-to-moderate AD patients will be enrolled. The intervention will consist of daily model-optimized and individualized tES delivered for 8 weeks, 5 days per week (40 sessions). tACS will be applied daily for 1 hour and will be paired with extensive neuroimaging, neurophysiological and neuropsychological evaluation at several time points (pre and post treatment) to better characterize patients and their response to treatment. The physiological target of treatment will be to increase gamma activity in the pre-frontal cortex, as this has been associated with cognitive decline in AD, and prior tES work targeting PFC gamma oscillations has shown promising results. The investigators hypothesize that active tACS treatment will result in a comparatively slower progression of cognitive decline and loss of gamma power as compared to sham treatment. To assess this, in this pilot study, a cross-over design will be used. Treatment will be multisession since prior tES work indicates a cumulative effect of each session with stronger therapeutic effects, in line with the underlying Hebbian mechanisms putatively involved in non-invasive brain stimulation.