Personalized non-invasive combined magnetic and electrical stimulation of the default mode network in mild AD patients (CMES-AD): a multicentric randomized sham-controlled trial protocol.

BACKGROUND: Patients with Alzheimer's disease (AD) exhibit early alterations in the Default Mode Network (DMN), a key brain network involved in episodic memory where the precuneus plays a central role. Precision-targeted, non-invasive brain stimulation represents a promising strategy to improve cognitive function in individuals with dementia. The DMN can be modulated through personalized non-invasive electromagnetic stimulation, a therapeutic approach that enhances neural plasticity and stabilizes network connectivity. This trial implements an innovative therapeutic protocol based on precision delivery of personalized electromagnetic stimulation targeting the precuneus, the main hub of the DMN.

METHODS: This phase 2 multicenter, randomized, double-blind, sham-controlled, three-arm trial evaluates the safety and efficacy of combined repetitive transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS) targeting the precuneus in AD patients. rTMS will be applied using the intermittent theta burst stimulation (iTBS) protocol, while tACS will be delivered at gamma frequency (70 Hz). Personalization of iTBS-tACS treatment is established using neuronavigated TMS with electroencephalography (TMS-EEG). The 24-week intervention starts with a 2-week intensive course of daily combined treatment over the precuneus (5 sessions per week), followed by a 22-week maintenance phase with weekly stimulation. The primary outcome measure is the change in the integrated Alzheimer Disease Rating Scale (iADRS) between baseline and week 24. Secondary outcomes include score changes in the Alzheimer's Disease Cooperative Study - Activities of Daily Living (ADCS-ADL) scale, Clinical Dementia Rating Scale-Sum of Boxes (CDR-SoB), the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog13), the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Frontal Assessment Battery (FAB), the Face-Name Association Task (FNAT), the Neuropsychiatric Inventory (NPI), and the Apathy Motivation Index (AMI). Exploratory outcomes will include changes in cortical activity and connectivity (assessed through TMS-EEG, MRI), in blood based biomarkers of neurodegeneration, synaptic activity and neural inflammation, and sensorimotor functions in virtual environments. Evaluation at week 12 and a follow-up assessment at week 32 will be conducted to assess short-term and follow-up treatment effects, respectively.

SIGNIFICANCE: This trial aims to provide evidence that personalized combined electrical and magnetic stimulation of the DMN may slow functional and cognitive decline in AD patients, contributing to the development of personalized interventions for AD treatment.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT07075770, registered 10 July 2025.